"We don't stop playing because we grow old; we grow old because we stop playing."
—George Bernard Shaw (1856–1950)
By the end of this chapter, readers will be able to:
Describe the age-related changes that are expected in cardiopulmonary and cardiovascular function.
Describe the factors that should be considered in prioritizing the goals of an intervention for cardiopulmonary and cardiovascular conditioning and provide the rationale.
Outline the focus of the assessment and the measures that would be most relevant to record based on the older adult's needs and wants.
Outline an intervention plan vis-à-vis prescribing training for cardiovascular and pulmonary function as these relate to activities of daily living and other areas of activity and participation.
Describe the precautions that are necessary when assessing and prescribing activities to enhance cardiopulmonary function.
Provide the rationale for deciding whether a maximal test or submaximal test is indicated.
On the basis of the findings of a maximal test or submaximal test: (a) outline the short-term and long-term responses expected for the intervention plan and (b) describe adverse responses the older adult could exhibit in response to the plan.
Mr. Miciej Kasper, aged 69 years, is a retired college professor. He was born in Poland and immigrated to the United States when he was 27 years old. His father died of heart disease. His mother lived to 88 years and had a history of high blood pressure. Other than having smoked a pack of cigarettes daily since he was 16 years old, Mr. Kasper reports good general health and that he has "never been sick a day in his life."
Although Mr. Kasper currently reports good health, what are the implications of his history on your assessment and decision-making?
Like many people, Mr. Kasper may have long-established beliefs and practices about health and well-being. How will you identify and consider these in your short- and long-term intervention plan?
This chapter focuses on the health of older people with special reference to the cardiopulmonary and cardiovascular systems. In contemporary rehabilitation practice, occupational and physical therapists appreciate the need to consider context, given that the lungs and heart do not function independently of the person in whom they reside. This topic is discussed in relation to the World Health Organization (WHO; 2001) definition of health and the International Classification of Functioning, Disability and Health (ICF), which frames the importance of physical activity with respect to what an individual needs or wants to do, and his or her capacity for activity and participation. Physical activity and exercise are key to offsetting age-related changes and maximizing function and health-related quality of life of older people. Physical activity and exercise reduce illness and disability, and their impact and may mitigate side effects of medical treatment. Considering the needs of older adults, the exercise-based means of assessing cardiopulmonary and cardiovascular status are described across the spectrum of meeting minimal requirements for performing daily activities, to having superior reserve capacity for increased physical capacity and functional independence, and potentially athletics. Irrespective of age, people have exercise conditioning potential that can be maximized, even in the presence of most chronic health conditions. Because exercise capacity is influenced by environment, ways in which an older person's environment might be modified to increase physical activity and reduce hazards—that is, by paying attention to contextual factors (environmental and personal in the ICF)—are outlined. The focus in this chapter is on changes associated with normal aging and on assessment and intervention designed to assist older adults in maintaining and enhancing cardiopulmonary function that supports function.
Increasingly, physical and occupational therapists work with well older adults—that is, those who, even if they have one or more chronic medical conditions, live in the community and engage in a range of daily activities that are important to them. To maximize the function of such individuals, therapists need to understand the impact of the older person's health behaviors, including nutrition, physical activity, and smoking, on the older adult's presentation, on the natural history of the condition(s), responses to intervention, and long-term functional prognoses. A baseline of these health behaviors provides the backdrop for the functional consequences of other conditions for which the older adult may be seeing the rehabilitation professional.
AROUND THE GLOBE: The Pandemic of Lifestyle-Related Noncommunicable Diseases
Unhealthy Western lifestyles (e.g., sedentary, diets high in processed foods) that are common in high-income countries are being adopted by people in low- and middle-income countries, such that lifestyle-related noncommunicable conditions are now appearing in the top 10 contributors to premature death (WHO, 2012).
Interrelationships Among Structure and Function, Activity, and Social Participation: Cardiovascular and Pulmonary Function
On the basis of the WHO's definition of health, the ICF (WHO, 2001) has become an important framework and basis for assessment and defining goals and outcomes of intervention for occupational and physical therapists (Chapter 2). Each individual is viewed as a whole such that his or her participation and quality of life are viewed distinctly, as well as interdependently with the capacity to perform activities and the integrity of anatomic structure and physiologic function. Specifically, activity includes activities of daily living (ADL) and those activities associated with participation and engagement in living. The ICF framework has particular relevance in health care today. First, this framework is consistent with a model of health versus illness care. Second, it is consistent with contemporary health-care priorities—namely, noncommunicable diseases (NCDs) that are lifestyle-related (i.e., ischemic heart disease, cancer, smoking-related conditions, hypertension and stroke, diabetes, and osteoporosis). The WHO has decreed that these conditions and their associated social and economic burdens are largely preventable (WHO, 2012). These conditions have achieved epidemic proportions. Furthermore, people are developing comorbidities earlier in their lives than in the past century because of unhealthy lifestyles. Because the biomedical model can maintain people's lives when threatened, people today experience long periods of morbidity, and particularly end-of-life morbidity, unless they pay attention to their lifestyle practices (specifically, nutrition, physical activity and exercise, smoking, sleep, and stress). Prolonged morbidity progressively limits a person's participation or quality of life.
With the increased predominance of lifestyle-related NCDs in high-income countries and the increasing predominance in low- and middle-income countries, and the chronicity of these diseases, there has been growing interest in quality-of-life issues.
Age-Related Changes in the Cardiopulmonary System and Its Function
Aging has a direct effect on each component of the cardiopulmonary system which includes the airways, lung parenchyma and its interface with the circulation (the alveolar capillary membrane), chest wall, and respiratory muscles. Ventilation of the alveoli and oxygenation of venous blood depends on the anatomic and physiologic integrity of these components (Koeppen & Stanton, 2010; West, 2012).
Aging is associated with a decrease in elastic tissue and an increase in fibrous tissue throughout the body's systems including the cardiopulmonary system. Because the large airways are predominantly rigid connective tissue, few changes with aging are reported. Because the medium and small airways are composed of less connective tissue and more smooth muscle, a decrease in the elasticity of these structures occurs with aging, resulting in reduced structural integrity of the tissue and increased compliance (compliance = Δvolume/Δpressure; increased compliance = increased stiffness).
The lung parenchyma is composed of spongy alveolar tissue that is designed to be ventilated and provide an interface with the pulmonary blood through the alveolar capillary membrane, which has a large surface area to promote the oxygenation of blood. Age-related increases in connective tissue and elastin disintegration reduce elastic recoil, the principal mechanism of normal expiration. The loss of normal recoil contributes to uneven distribution of ventilation, airway closure, air trapping, and impaired gas exchange. The net result of these changes is a decrease in alveolar surface area, hence reduced efficient gas exchange.
Alveolar Capillary Membrane
The alveolar capillary membrane is uniquely designed to optimize the diffusion of gases between the alveolar air and the pulmonary circulation. The diffusing capacity, the ability of oxygen (O2) to diffuse from the alveolar airspaces into the pulmonary capillary, progressively declines with age and has been attributed to reduced alveolar surface area, alveolar volume, and pulmonary capillary bed.
The chest wall is composed of the structures separating the thorax from the head and neck, the diaphragm separating the thorax from the abdomen, the rib cage, the intercostal muscles, and the spinal column. With age, the joints of the thorax become more rigid, and cartilage becomes calcified; hence, the chest wall becomes less compliant. The chest wall becomes barrel shaped, the anteroposterior diameter increases, and the normal three-dimensional motion of the chest wall during the respiratory cycle is diminished.
The diaphragm, the principal muscle of respiration, tends to flatten with age-related hyperinflation of the chest wall, reduced lung compliance and air trapping in the lungs, and is possibly secondary to reduced muscle mass. Loss of respiratory muscle mass parallels the age-related reduction in skeletal muscle mass in general. Loss of abdominal muscle strength reduces the force of coughing, which can contribute to impaired airway mucociliary clearance and aspiration.
Net Effect of Age-Related Cardiopulmonary Changes
These anatomic changes give rise to predictable physiologic or functional changes in pulmonary function after the cardiopulmonary system has matured (see Table 8-1). Respiratory mechanics that largely reflect the resistance to airflow and the compliance of the chest wall and lung parenchyma are altered with aging. Specifically, both airflow resistance and lung compliance increase. With respect to cardiopulmonary function, forced expiratory volumes and flows and inspiratory and expiratory pressures are reduced. Functional residual capacity and residual volume are increased. These effects are further accentuated in recumbent positions. Arterial oxygen tension and saturation are also reduced linearly with age. Thus, progressively over the life cycle, the lung becomes a less efficient gas exchanger.
TABLE 8–1Age-Related Changes in the Cardiopulmonary System and Its Function ||Download (.pdf) TABLE 8–1 Age-Related Changes in the Cardiopulmonary System and Its Function
|MORPHOLOGICAL AND STRUCTURAL CHANGES ||FUNCTIONAL SIGNIFICANCE |
|Calcification of bronchial and costal cartilage ||↑ Resistance to deformation of chest wall |
|↑ Stiffness of costovertebral joints ||↑ Effective use of accessory respiratory muscles |
↑ Anteroposterior diameter
↑ Wasting of respiratory muscles
↓ Tidal volume
↑ Exercise-induced hyperpnea
↓ Maximal voluntary ventilation
↓ Force of cough
↑ Risk of aspiration or choking
↑ Size of alveolar ducts
↓ Supporting duct framework
↑ Size of alveoli
↑ Mucous glands
↑ Alveolar compliance
↓ Surface area for gas exchange
↑ Physiologic dead space
↓ Elastic recoil
↓ Vital capacity
↓ Inspiratory reserve volume
↑ Expiratory reserve volume
↑ Functional residual volume and residual volume
↓ Ventilatory flow rates
↓ Distribution of ventilation
↑ Closure of dependent airways
↑ Arterial desaturation
↑ Resistance to airflow in small airways
↓ Pulmonary capillary network
↓ Distribution of perfusion
↑ Impaired diffusion capacity
↑ Fibrosis of pulmonary capillary intima
↓ Ventilation to perfusion matching
Age-Related Changes in the Cardiovascular System and Its Function
The cardiovascular system is composed of the heart and vas-culature. The left side of the heart is responsible for pumping blood that has been oxygenated in the lungs throughout the body to all the cells of the organ systems via the arterial vas-culature. The venous vasculature is responsible for returning blood that has been partially deoxygenated and contains metabolic waste products, including carbon dioxide, to the right side of the heart when it is pumped through the lungs to be reoxygenated. Other metabolic waste products are cleared as the blood flows through the kidneys, gut, and liver. Clearance of such wastes and cellular debris is also facilitated by the lymphatic drainage system. Although loss of efficiency of the cardiovascular and lymphatic systems may occur with age, high levels of functioning of these systems can be maintained throughout the life cycle when lifestyles are optimized.
Age-related fibrotic changes in the heart's specialized nerve conduction system may result in abnormal cardiac impulses. Electrocardiographic irregularities such as premature ventricular contractions, atrial fibrillation, and heart blocks are common in people over 65 years of age (Fleg & Lakata, 2008). Medications can often help stabilize or regulate the heart's electrical activity; however, artificial pacemakers may be implanted when medications do not work.
The heart pumps less effectively with age due to changes in the mechanical properties of the cardiac muscle, which alter its length-tension and force-velocity relationships. Additionally, changes with age in both the integrity of the valves—the atrioventricular valves, the pulmonic valve, and the aortic valve—and variations in the aging cardiopulmonary and cardiovascular systemic circulations can result in less efficient pumping action of the heart (Strait & Lakatta, 2012). Histologically, the heart tissue becomes fattier, and both heart mass and volume increase. Amyloidosis, a histologic feature of aging observed in many organs including the heart and vasculature, is characterized by the progressive deposition of amyloid protein. This waxy protein infiltrates tissue, rendering it dysfunctional. In general, the walls of the heart become more compliant with age. The myocardial fibers no longer contract at optimal points on the length-tension or force-velocity curves, which reduces the efficiency of myocardial contraction, in turn, the capacity for effective cardiac output.
Blood vessels require varying degrees of distensibility or compliance depending on their specific function. The forward motion of blood on the arterial side of the circulation is a function of the elastic recoil of the vessel walls and the progressive loss of pressure energy down the vascular tree. The decrease in elasticity of the arterial vessels with aging may result in chronic or residual increases in vessel diameter and vessel wall rigidity, which impair the function of the vessel. The reservoir function of the venous circulation is dependent on its being highly compliant to accommodate the greatest proportion of the blood volume at rest. Although the mechanical characteristics of venous smooth muscle have been less well studied compared with arterial smooth muscle, the efficiency of its contractile behavior can be expected to be reduced with aging. Furthermore, its electrical excitability and responsiveness to neurohumoral transmitters tend to be less rapid and less pronounced.
The ability of the vasculature to move blood through the vascular system and shift volumes of blood between vascular beds depending on need is diminished with aging; the rapidity with which these changes can be effected is correspondingly reduced. The ability to effect these vascular adjustments in response to gravity and exercise are tantamount to effective physical functioning.
Net Effects of Age-Related Cardiovascular Changes
The age-related anatomical and physiological changes of the heart and blood vessels result in reduced capacity for oxygen transport at rest and, in particular, in response to situations imposing an increase in oxygen demand of metabolically active tissue (particularly skeletal muscle) for oxygen (see Table 8-2). Therefore, activities associated with a relatively low metabolic demand are perceived by older persons as physically demanding. Certain activities may no longer be able to be performed, whereas others may require rest periods in between. Many older people have electrical conduction abnormalities at rest and in the absence of clinical heart disease (Fleg & Lakatta, 2008), which has major implications for the mechanical behavior of the heart and the regulation of cardiac output, particularly when stressed during activity and exercise.
TABLE 8–2Age-Related Changes in the Cardiovascular System and Its Function ||Download (.pdf) TABLE 8–2 Age-Related Changes in the Cardiovascular System and Its Function
|MORPHOLOGICAL AND STRUCTURAL CHANGES ||FUNCTIONAL SIGNIFICANCE |
↑ Fat constituents
↑ Fibrous constituents
↑ Mass and volume
↑ Lipofuscin (by-product of glycogen metabolism)
↑ Amyloid content
↓ Specialized nerve conduction tissue
↓ Intrinsic and extrinsic innervation
↑ Connective tissue and elastin
↓ Cardiac output
↓ Venous return
↑ Cardiac dysrhythmias
|Blood Vessels |
|↑ Loss of normal proportion of smooth muscle to connective tissue and elastin constituents || |
↓ Blood flow to oxygenate tissues
↓ Blood flow and risk of clots in venous circulation
↑ Rigidity of large arteries
↑ Atheroma arterial circulation
↑ Dilation and tortuosity of veins
↓ Cardiac output
↓ Venous return
Functional Consequences of Age-Related Cardiopulmonary and Cardiovascular Changes
Exercise is fundamental to activities that require some degree of endurance, demanding the maintenance of increased oxygen transport and tissue oxygenation. Although some types of activity, such as card playing or watching television, require a greater metabolic demand than is required when one is strictly at rest, the increased metabolic demand is typically minimal and not usually sustained.
The Functional Performance Threshold
The ability to perform ADL to meet the minimum criterion compatible with personal care and independent living can be thought of as a functional performance threshold (Young, 1986). Young people have considerable physiological capacity and reserve that enable them to perform activities and exercise well in excess of the metabolic and physical demands required by routine daily activities. With aging, however, changes in the various organ systems—that is, lungs, heart, nervous system, endocrine system, and musculoskeletal systems—reduce physiological capacity and reserve. If physical decline results in a functional capacity below the functional performance threshold, the minimum criteria for self-care and independent living cannot be met. Falling below this threshold can be a result of progressive age-related changes, restricted mobility, or health condition(s) sufficient to lower an individual's already minimal reserves.
The rate of decline in functional capacity with age and the decline in functional performance are qualitatively different. Although functional capacity deteriorates linearly with advancing age, the decrease in functional performance declines in a curvilinear manner. Thus, an older adult can lose significant capacity yet retain considerable function over the years.
Metabolic Demand of Activities of Daily Living and Exercise
The metabolic demand of an activity can be defined by the unit called the metabolic equivalent (MET). One MET is equal to 3.5 mL O2/kg of body weight per minute, the normal basal metabolic demand for oxygen (American College of Sports Medicine [ACSM], 2013, 2014). By convention, the metabolic demands of various activities are expressed as multiples of the basal metabolic rate. A list of typical activities with their associated METs can be found in the online ancillary materials. Although scarce, research conducted over the past decade has found that metabolic costs of daily activities and walking are substantially different in older adults (Jones, Waters, & Legge, 2009; Knaggs, Larkin, & Manini, 2011) and that having mobility impairments increases metabolic cost (Knaggs et al., 2011). It is thought that poor efficiency of movement, exacerbated by co-activation of antagonistic muscle groups, is partially responsible for elevated costs (Mian, Thom, Ardigo, Narici, & Minetti, 2006). These differences are important for rehabilitation professionals to consider when prescribing activities and exercise for healthy and mobility impaired older adults.
It can be somewhat difficult to know the metabolic cost of some activities that are important to older adults. For example, the metabolic costs of sexual activity and the capacity to work have been relatively neglected in the literature, particularly with respect to older people. Metabolic cost of sexual activity in young people depends on the body position and other factors and is relatively low. Sexual activity is equivalent to 3 to 5 METs (climbing two flights of stairs or walking briskly for a short duration). Considering an older person's capacity for physical activity (Levine et al., 2012) and the variations in hemodynamic status that occur during sexual activity, it can be well tolerated for many older people (Steinke, 2014). If aerobically conditioned, an older person can perform sexual activity, such as intercourse, without excessive heart rate, blood pressure, and overall exertion responses (Palmeri et al., 2007). However, sexual activity may be less well tolerated in older adults with cardiovascular conditions leading to heart palpitations, shortness of breath, and fatigue (Thorson, 2003). To minimize the metabolic demand and exercise stress, sexual encounters can be timed with medications and with energy peaks during the day, and body positions can be modified. For example, upright positions may be better tolerated than recumbency.
Increased longevity and the elimination of mandatory retirement have increased interest in vocational assessment for older people. The American Thoracic Society (1986) guidelines suggest that if a given occupation exceeds 40 percent of an individual's peak O2 consumption in an exercise test, an individual would not be able to tolerate working at that occupation for prolonged periods. Research is needed to refine and extend these guidelines for older persons who are considering changing occupations or reentering the labor force, both for vocational capacity and safety.
Progressive changes in the cardiopulmonary and cardiovascular systems, in conjunction with changes in the capacity for oxygen and substrate utilization in the musculature, result in less efficient oxygen transport in the older adult. With activity and exercise, the increased metabolic demand for oxygen and substrate requires a commensurate increase in ventilation and cardiac output. Both maximal ventilation and cardiac output decline linearly with age, and maximal oxygen consumption is correspondingly reduced. The extraction of oxygen at the tissue level, however, which is measured by the arteriovenous oxygen difference, does not change significantly with age. The degree of endurance needed to perform ADL varies depending on the task. Those ADL that are primarily skill based, such as dressing, toileting, grooming, shaving, bathing, and feeding, are associated with low metabolic demand and generally require little endurance. Functional limitation in skill-based ADL in older persons tends to reflect musculoskeletal or neuromuscular deficits rather than difficulties with oxygen transport or gas exchange. However, ambulation, climbing stairs and hills, yard work, housework, shopping, gardening, sexual activity, volunteer work, gainful employment, managing transportation, and social activities outside the home are associated with higher metabolic demand, require greater endurance and tend to reflect the status of the cardiopulmonary and cardiovascular systems.
Whether an active lifestyle contributes to or results from cardiopulmonary and cardiovascular conditioning warrants discussion. The question can best be addressed by examining the elements of aerobic conditioning. To elicit an aerobic training response, the stimulus must be of sufficient intensity, frequency, and duration and be carried out over a prolonged period. The critical parameters of the prescription needed to effect an aerobic training response are the performance of aerobic exercise for 20 to 30 minutes at 60 to 70 percent of the maximum oxygen consumption that is associated with a heart rate between 70 and 80 percent of the maximum heart rate for a minimum of 3 days a week for 3 to 6 months (ACSM, 2013). The physiological adaptations that result from aerobic conditioning reflect an increased ability to transport oxygen and to use oxygen and metabolic substrates at the tissue level.
Depending on an individual's age, most typical activities are not performed at a sufficient intensity, duration, or frequency or over a sufficient time period to effect long-term aerobic adaptations. However, habitual activity does maintain sufficient physiological adaptation to perform tasks associated with low metabolic demand. Given that maximal heart rate and aerobic capacity diminish with age, even skill-based ADL can become aerobically demanding. For example, routine walks down hospital corridors can be associated with an intensity of exercise that exceeds acceptable limits in some older adults using walkers (Baruch & Mossberg, 1983). This scenario is one in which older individuals are frequently not monitored. Routine tasks and activities not considered to be metabolically demanding must be analyzed at two levels: their relative physiological demand on a given individual and the individual's capacity to meet that metabolic demand such that the adaptation that is elicited is both therapeutic and safe.
Cognitive decline has been associated with aging and reduced functional performance and independence. Such decline can be associated with reduced midlife activity and may be offset with regular physical activity and exercise (Behrman & Ebmeier, 2014). Because of the interdependence of cognitive function and physical performance in older people, baseline and serial assessments of cognitive capacity (see Chapter 7) can be informative, particularly when activity and exercise programs are being prescribed. Keep in mind, too, that exercise is associated with musculoskeletal factors and with maintaining gait and balance (Chapters 10 and 11).
Assessing Functional Performance
The objective of the assessment of functional performance is to determine the older adult's ability to perform daily activities. Functional performance reflects the capacity to perform work. Nutritional status and body weight are important components of the assessment of a person's capacity to perform work. When nutritional status is optimal, an individual will be better able to engage in regular physical activity and structured exercise programs (see Fig. 8-1).
The modified MyPlate for older adults.
Numerous performance tests have been described in the literature (Carey & Posavic, 1982; Katz, Ford, Moskowitz, Jackson, & Jaffe, 1963; Kruiansky & Gurland, 1976; Linn & Linn, 1982; MacKenzie, Charlson, DiGioia, & Kelley, 1986; Mahoney & Barthel, 1965). Additional information about evaluation of performance can be found in Chapter 27 and in the online ancillary materials. Such tests must be performed according to standardized criteria to ensure their validity and reliability. A major liability of these tests is that monitoring is seldom considered an integral component; however, appropriate monitoring is vital to avoid underestimating the physiological demand placed on the older adult. Although fundamental to normal function, movement constitutes a physiological stressor and thus is inherently risky, particularly in older persons. Adverse effects may include abnormal heart rate, blood pressure, and breathing frequency; cardiac dysrhythmias; altered intraabdominal and thoracic pressures; reduced venous return, stroke volume, and cardiac output; orthostatic intolerance; and blood glucose swings. In turn, the work of breathing and of the heart may be excessive, which adds further to the overall metabolic cost of the activity.
Assessing the person's ability to perform an activity should be viewed as a unique form of exercise test. Although motor control and performance may be the focus of ADL reeducation, important cardiovascular and pulmonary responses should be monitored at least initially. Baseline measures including heart rate and rhythm, breathing frequency, systolic and diastolic blood pressure, rate pressure product (the product of heart rate and systolic blood pressure, which is highly correlated with myocardial oxygen consumption and the work of the heart), and perceived exertion provide valuable information about an older adult's ability to perform an activity. One of the most commonly used scales for rating perceived exertion is the Borg's scale, and this has been adapted to other symptoms such as pain and fatigue (Table 8-3).
TABLE 8–3Subjective Scales of Exercise Responses ||Download (.pdf) TABLE 8–3 Subjective Scales of Exercise Responses
| ||PERCEIVED EXERTION ||BREATHLESSNESS ||DISCOMFORT/PAIN ||FATIGUE |
|0 ||Nothing at all ||Nothing at all ||Nothing at all ||Nothing at all |
|0.5 ||Very, very weak ||Very, very light ||Very, very weak ||Very, very light |
|1 ||Very weak ||Very Light ||Very weak ||Very Light |
|2 ||Weak ||Light ||Weak ||Light |
|3 ||Moderate ||Moderate ||Moderate ||Moderate |
|4 ||Somewhat strong ||Somewhat strong ||Somewhat strong ||Somewhat strong |
|5 ||strong ||Hard ||strong ||Hard |
|7 ||very strong ||very strong ||very strong ||very strong |
|10 ||Very, very strong/maximal ||Very, very strong/maximal ||Very, very strong/maximal ||Very, very strong/maximal |
Occupational and physical therapists need a thorough understanding of the physiological demands of the activity or exercise that the older adult is performing, so that the exercise response can be anticipated and is appropriate. For example, aerobic activities with incremental work rates, preferably involving the legs, will result in a commensurate increase in heart rate, blood pressure, breathing depth and rate, and increased perceived exertion. Activities involving primarily the arms, such as hair combing or snow shoveling (an activity often associated with myocardial infarction), result in a disproportionate increase in blood pressure and work of the heart compared with dynamic leg exercise. Arm exercise may be a justifiable alternative for people with leg limitations (Fig. 8-2); however, these activities need to be monitored closely in the older person because of changes in ability to recover from exertion and the potential for longer-term recovery from any injury.
Although this man has difficulty walking, he is able to work toward enhancing his functional capacity, using an arm ergometer to exercise. (Courtesy of the Geriatric Day Hospital, Specialized Geriatric Services, Saskatoon Health Region, Saskatoon, Saskatchewan, with permission).
Many ADL require a change in body position, such as getting out of bed, the tub, or a chair or picking up an item from the floor. Although these activities may not be metabolically demanding, they lead to significant fluid shifts secondary to the effect of gravity and have profound hemodynamic consequences. Because the fluid-volume-regulating mechanisms in older persons may be blunted, dizziness, blackouts, or fainting can result. Thus, the hemodynamic status of these individuals needs to be monitored until the therapist is sure that these activities can be safely performed. Activities such as getting out of bed, the tub, or a chair, or getting off the toilet may appear comparable; however, the mechanisms of orthostatic intolerance—that is, postural hypotension—associated with each activity can differ. Getting out of bed in the morning may be accompanied by morning stiffness, imbalance, slowed vital signs, slowed autonomic responsiveness, and reduced muscle pump activity in the legs. Getting out of the tub is associated with significant peripheral vasodilation from having been in warm water for a period of time. Thus, adaptation of the normal fluid shifts will be poorer on assuming the standing position. In addition, there is enormous drag in lifting oneself out of water either in the tub or a swimming pool, and increased cardiac work is required secondary to the postural stabilization. Getting off the toilet may follow a period of autonomic changes and physical straining and hence may result in reduced venous return. Orthostatic intolerance associated with getting out of a chair may reflect fluid shifts and pooling of blood in the abdomen and legs during sitting. Finally, orthostatic intolerance associated with picking an item off the floor may reflect reduced cerebral blood flow secondary to the sudden movement to the erect position and the lack of the normal rapid compensatory response. Observing and monitoring the objective and subjective responses to changes in body position enables the occupational and physical therapist to make specific recommendations aimed at reducing the risk of blackouts, fainting, and dizziness.
Another critical factor that may have significant effects on an older person's ability to perform an activity or exercise is impaired thermoregulation. Older people have a reduced capacity to thermoregulate and report being hypothermic (Kemp, Després, Pebayle, & Dufour, 2014), and potentially have an impaired ability to lose exercise-induced body heat. The increase in peripheral blood flow to dissipate heat during activity, especially in a warm ambient environment, may compromise cardiac output and blood flow to the working muscles. Failure of blood pressure regulating mechanisms may be responsible. Activity in warm environments taxes the older adult to an even greater extent and may exacerbate congestive heart failure and dehydration. The older adult may have signs and symptoms of lightheadedness, disorientation, instability, fainting, and heart irregularities. Some common submaximal tests of functional performance, the validity, reliability, and safety of which have been established in older subjects, can be found in the online ancillary materials. These include the self-paced walking test (SPWT; Bassey, Fentem, MacDonald, & Scriven, 1976; Cunningham, Rechnitzer, Pearce, & Donner, 1982), modified shuttle walking test (MSWT; Singh, Morgan, Hardman, Rowe, & Bardsley, 1994; Singh, Morgan, Scott, Walters, & Hardman, 1992), bag-and-carry test (BCT; Posner et al., 1995), timed up and go test (TUGT; Mathias, Nayak, & Isaacs, 1986; Podsiadlo & Richardson, 1991), and the 6- and 12-minute walk test (6- and 12-MWT; McGavin, Artvinli, Naoe, & McHardy, 1978; McGavin, Gupta, & McHardy, 1976).
Functional capacity refers to the capacity to respond to an exercise stimulus, maintain the physiological adjustments necessary to sustain aerobic exercise for a period of time (work), and then recover appropriately from that stimulus on cessation of exercise. Although this capacity declines with increasing age, individual differences among older people are considerably greater than among young people. The nutrition and physical activity and exercise icon illustrates the general principles for various levels of physical activity for optimal health irrespective of age (see Fig. 8-1).
Assessing Functional Capacity
Assessing functional capacity involves determining an individual's peak aerobic power or ability to sustain aerobic exercise over time. These assessments are typically based on the results of a peak exercise test or endurance test. Although exercise testing is a well-established practice for individuals with cardiopulmonary and cardiovascular dysfunction, as well as for healthy people, exercise testing and training in older age-groups is not as advanced. This may reflect the inherent challenges of dealing with older age-groups related to the prevalence of multisystem complications such as arthritis, cardiopulmonary and cardiovascular dysfunction, hypertension, obesity, diabetes, thyroid problems, depression, and cognitive impairment. Although peak aerobic power may be of physiological interest in older people, endurance is likely to have greater practical value with respect to functional capacity overall.
To assess functional capacity in young people, maximum exercise testing is considered the gold standard. The results of a maximum exercise test provide a profile of the individual's capacity to transport oxygen during progressive increments in work rates and the upper limit of oxygen consumption for that individual. Although maximum tests have a role in assessing older athletes, they are of less value in assessing older people in general. Maximum exercise tests are neither feasible nor necessarily safe for many nonathletic older people, and the criterion for defining the test as a true maximum test is unlikely to be achieved in this population. Instead, peak or submaximal exercise tests are used in older people because they provide practical information regarding an individual's functional capacity and endurance. In a maximum exercise test, the individual undergoes an incremental protocol until the maximum oxygen consumption is reached. Submaximal testing is associated with less risk, is more pleasant to perform, and can be readily administered by a knowledgeable rehabilitation professional.
Principles for selecting and administering submaximal exercise tests have been described in detail in the literature (Noonan & Dean, 2000); the clinical decision-making process is summarized in Box 8-1. The goal of the test needs to be determined and a decision made as to whether a symptom or sign limited test, or both, or a steady-state exercise test is indicated. Submaximal tests can be used to predict maximal oxygen uptake of older people with predictions most often using measures of heart rate and perceived exertion (Evans, Ferrar, Smith, Parfitt, & Eston, 2015; Smith, Eston, Norton, & Parfitt, 2015).
BOX 8–1 Principles for Selecting and Administering Submaximal Exercise Tests
Appropriateness of time of day for activity or exercise for individual
Quality of night's sleep
Activity before the session (e.g., visitors, tests, agitation, or irritations)
Discomfort or pain
Timing with respect to medications
Types of changes in medications
Lability of vital signs or hemodynamic instability
Interest and motivation
ESTIMATE FUNCTIONAL CAPACITY
Estimate based on history and assessment
Possible outcomes: high, intermediate, or low
IF THE ESTIMATED FUNCTIONAL CAPACITY IS HIGH*
Peak exercise test
Continuous incremental protocol on treadmill or ergometer
Maximal Exercise Test
Continuous incremental protocol on treadmill or ergometer (Note: Depending on the individual's age, history, and assessment, either type of test may require a physician present.)
High metabolic demand
Test End Points
Based on the history and assessment, determine relative and absolute end points that indicate the discontinuation of ADL or exercise
IF THE ESTIMATED FUNCTIONAL CAPACITY IS INTERMEDIATE
Submaximal exercise test
Continuous incremental or steady-state protocol on modality or 6- or 12-min walk test
Intermediate metabolic demand
Test End Points
IF THE ESTIMATED FUNCTIONAL CAPACITY IS LOW
Submaximal exercise test
Interrupted protocol on modality or 3- or 6-min walk test
Low metabolic demand either interrupted or uninterrupted
Test End Points
Level of monitoring before, during, and after testing determined by history and assessment
Systolic and diastolic blood pressure
Rate pressure product (product of heart rate and systolic blood pressure provides an index of myocardial oxygen consumption and work of the heart)
Chest or breathing discomfort
General discomfort or pain
Other parameters: color, perspiration, orientation, coordination, stability, facial expression, comfort, and ability to talk
Arterial saturation (noninvasive pulse oximeter)
Respiratory gas analysis† (i.e., oxygen uptake, minute ventilation, tidal volume, etc.)
Cardiac output (can be determined noninvasively)
Serum enzymes and lactate (require blood work)
Endurance can be tested with either a continuous steady-state test or a test involving an interrupted protocol for individuals with very low functional work capacity. To maximize exercise test validity and reliability pretest conditions need to be standardized. The findings of the test can then be used confidently as the basis for assessment and evaluation, and for comparing the findings of subsequent tests. Because it may be difficult to standardize pretest conditions, it is important to record them to clarify what has differed from one administration to the next. A sample checklist is provided in the online ancillaries. Differences in one or more pretest conditions could explain a performance difference between tests that is independent of a change in the older adult's status or response to an exercise intervention. Such differences include change in body mass, different medication regime, time of day of exercise test, food and beverage intake close to exercise time, and quality of the previous night's sleep. The recording of the exercise test is best done systematically on a data sheet. Samples of these sheets can be found in the ancillary materials online. Data sheets can record such assessment as a treadmill or ergometer test or as a self-paced walking test or circuit type of test. The tester needs to establish what objective measures and subjective measures will be recorded before the test. Several baseline measures are recorded every minute, with the individual standing or sitting quietly and not talking. These conditions ensure that true resting measures are obtained. A decision is also made beforehand regarding what measures will be taken during the test, if any. Minimally, pre- and posttest measures are recorded. Postmeasures include those taken during the cool-down period if a cool down is needed. The older adult remains sitting quietly at the end of the recovery period or at end of the active part of the test, so that valid and reliable recovery measures are obtained. The end of the test is denoted by when the vital signs and the subjective measures return to baseline or stabilize at near baseline values. Finally, indications for terminating an exercise test need to be established beforehand. Should the test be terminated prematurely, the reason is recorded on the data sheet—that is, was the test terminated as expected, and if not, what was the precise reason?
Considerable research is needed to maximize the validity and reliability of submaximal exercise testing procedures and thereby to increase the diagnostic and clinical value of performing these tests in populations in which maximum testing has fewer indications. Despite their limitations, if carefully administered and the procedures appropriately documented, submaximal exercise testing can provide a basis for prescribing activity and exercise that is both therapeutic and safe for older people (ACSM, 2013, 2014).
Functional Consequences of Fitness in Older People
People tend to become less active as they age. The effects of deconditioning with inactivity have been well documented over the past 60 years and are multisystemic (Mackinnon, 2000; Mascitelli & Pezzetta, 2004). Other than reduced respiratory muscle strength and endurance, most of the effects of restricted mobility on the cardiopulmonary system have been those associated with recumbency and bedrest (see Fortney, Schneider, & Greenleaf, 2011, for a summary of decades of research) including the following:
reduced lung volumes and capacities, with the exception of closing volume of the airways, which increases;
reduced alveolar-arterial oxygen difference and arterial oxygen tension;
increased resting and submaximal heart rates and blood pressure;
reduced maximal oxygen consumption;
reduced total blood volume and plasma volume; and
increased blood viscosity, which increases the risk of thromboembolism (Fortney et al., 2011; Kortebein, et al., 2008).
The rate of deconditioning has been reported to exceed that of conditioning (Kortebein et al., 2008), which has particular consequences in the older individual with less physiological reserve. The effects of deconditioning are accentuated in older people. Older men and women may decondition differently. Men and women residing in a long-term facility have been reported to differ in terms of physical fitness components and functional performance (Singh, Chin, Paw, Bosscher, & van Mechelen, 2006). Although functional performance was not different between the two sexes, peripheral muscle strength and eye-hand coordination were reported to be better preserved in deconditioned men in the facility, whereas women were more flexible and had superior motor coordination. These findings have implications for rehabilitation assessments and potential interventions indicated.
Training elicits the same physiological benefits with respect to oxygen transport and oxygen and substrate use and comparable magnitudes of change in aerobic power and strength in older persons as those seen in younger people (e.g., Coetsee & Terblanche, 2015; Mendelsohn, Overend, Connelly, & Petrella, 2008; Puggaard, 2003; Vaitkevicius et al., 2002), and these effects are still apparent in individuals with chronic diseases. Submaximal heart rates, blood pressure, and ventilatory rates are reduced. Stroke volume increases, and oxygen extraction at the tissue level is also increased. Comparable to young people, exercise can augment peripheral vasodilatation in older adults, which supports the preservation of vascular plasticity in this population (Wray, Uberoi, Lawrenson, & Richardson, 2006). Further, aerobic fitness can improve the plasticity of the brain and, thus, may reduce cognitive as well as physical age-related changes (Colcombe et al., 2004). These improvements translate into increasing functional capacity over and above the critical functional performance threshold (Coetsee & Terblanche, 2015; Mendelsohn, Overend, Connelly, & Petrella, 2008). Older people, however, may increase their maximal cardiac output and stroke volume in response to training, in favor of peripheral adaptation (Spina, Rashid, Davila-Roman, & Ehsani, 2000).
Even though the absolute metabolic cost is theoretically constant, older people experience a given activity as more physiologically demanding than younger people because of the reduced capacity of their oxygen transport systems and their musculature to respond to the physical demand. Decline in the economy of movement in older adults may also contribute (Thomas et al., 2011). Thus, even fit older people report that activities such as walking, climbing stairs, and carrying objects are demanding. With increasing age, these seemingly innocuous activities can be the equivalent of a maximal effort and may increase an older individual's heart rate, blood pressure, and oxygen consumption to maximal values.
The prescription parameters of an exercise program are based on the results of an exercise test. The clinical decision-making process involved in defining the parameters of an exercise program has been described in detail in the literature previously (Dean & Butcher, 2012a, 2012b) and is summarized in Box 8-2. However, there are two additional principles of exercise physiology that have particular relevance in prescribing therapeutic activity and exercise for older people—namely, the principles of training specificity and reversibility. The human body is extremely efficient in that physiological adaptation to exercise stress is unique to a specific activity or exercise. Thus, to improve an individual's ability to perform an activity, that activity should be the primary object of training. The lower the initial functional capacity, the more significant is the principle of specificity. Also, once training has been discontinued, the training effect does not carry over, and deconditioning begins immediately. Thus, to maintain a given level of activity or exercise, the training stimulus must be presented at the required intensity, duration, and frequency and over the requisite period of time that is consistent with eliciting physiological adaptation (ACSM, 2013, 2014).
BOX 8–2 Principles for Prescribing Activities of Daily Living (ADL) and an Exercise Program
PRESCRIPTION OF DAILY ACTIVITIES TO ENHANCE CARDIOPULMONARY CAPACITY
To maximize functional performance by promoting the appropriate physiological adaptation and task endurance, with maximum movement economy, comfort, and least risk
Based on individual's needs; prioritize
Activity Phases: If feasible, tailor a specific ADL or sequential ADL into:
Warm-up (up to 75 percent of the intensity for the steady state)
Steady state (performed within target range based on predetermined levels of physiologic or subjective variables)
Recovery (monitored until within 10 percent of baseline values, and individual appears to have returned to baseline)
Lower target limit: None other than pathologically low values for physiological variables (e.g., consistent with a hypotensive episode)
Upper target limit: Physiological variables not to exceed a predetermined level of physiological variable (e.g., heart rate, blood pressure, exertion level, or subjective experience of exertion, breathlessness, discomfort or pain, fatigue, chest pain)
If recovery is less than 30 min, patient can likely tolerate an increase in duration
If recovery is between 30 min and 3 h, duration is probably optimal.
If recovery is longer than 3 h, duration is likely too long. (This recovery excludes the anticipated cumulative fatigue over the course of the day.)
If recovery is within 30 min, likely too infrequent
If recovery is between 30 min to 3 h, optimal frequency
If recovery is longer than 3 h, likely too frequent
Based on adaptation to performance criterion, optimal movement economy, sufficient cardiopulmonary—cardiovascular conditioning, velocity, and safety
Reduce demands of activity if individual is consistently in the upper limit of the target range; individual can tolerate higher demand activities if the physiological responses are not consistently reaching the target therapeutic range.
If low functional work capacity, performance and adaptation are enhanced with lighter-intensity, shorter, more frequent sessions.
IF ESTIMATED FUNCTIONAL CAPACITY IS HIGH
To maximize functional capacity by promoting physiological adaptation to an exercise stimulus, with maximum movement economy, comfort, and safety, and thereby increase functional capacity reserve above the functional performance threshold commensurate with the individual's needs if the estimated functional capacity is high
Based on goals and results of the exercise test
If normal exercise response and adaptation can be expected, then steady-state exercise at 70 to 85 percent of peak physiological parameters on peak test (e.g., heart rate, blood pressure, perceived exertion)
If abnormal aerobic responses and adaptation to exercise are expected (e.g., chronic airflow limitation, restrictive lung disease or heart disease), define target training range on the basis of breathlessness scale, exertion, or chest pain provided that physiological parameters remain within acceptable limits
20 to 40 min per session
3 to 5 times per week
In health, 3 to 6 months; but in sedentary persons, change can be observed in 4 to 8 weeks
With adaptation, target range is no longer maintained (i.e., heart rate, blood pressure, and exertion levels consistently below selected range based on initial exercise test); progression based on a repeated exercise test to redefine exercise prescription parameters
IF ESTIMATED FUNCTIONAL CAPACITY IS INTERMEDIATE
Set between those for high and low
For example, treadmill, ergometer, walking, swimming, water exercises
60 to 75 percent of peak work rate achieved on exercise test
20 min or less
One or two times per day
With pathology, can expect prolonged course
Maintain exercise parameters: if exceeding values, cut back; if consistently below, can increase the duration or frequency
IF ESTIMATED FUNCTIONAL CAPACITY IS LOW
For example, walking, water exercise, and general light activity or exercise
Based on heart rate: lower limit = resting heart rate + 0.60 (peak heart rate from the exercise test resting heart rate)
Upper limit = resting heart rate + 0.80 (peak heart rate from the exercise test—resting heart rate)
If heart rate inappropriate or invalid measure of exercise intensity, blood pressure, perceived exertion, or the talk test
Can be used to define the target training range
Maximize tolerance by maintaining power output constant and velocity changes to maintain perceived exertion constant
Emphasis on prolonging duration by using an interrupted regimen of alternating higher and lower demand work, or low-demand work with rest
Several times daily guided by pre-exercise-session check
If reduced functional capacity due to deconditioning, adaptation will be observed daily and weekly
If reduced functional capacity due to physical limitations, it is weeks to months for central or peripheral adaptation, or both, to occur
Exercise progressed as soon as the target training parameters are no longer consistently reached in the exercise session
Refer to guidelines in online ancillary materials
Essential to guide exercise prescription, training, and for general safety
Implications for the Management of the Care of Older People
The primary outcome of rehabilitation for older people is maximizing function and occupational performance, of which physiologic (cardiopulmonary and cardiovascular) capacity and reserve are significant determinants.
Two principal goals to maintain cardiopulmonary function for older people are to:
maximize the cardiopulmonary and cardiovascular reserve capacity such that this capacity exceeds an individual's critical functional performance threshold with consideration of physical activity and exercise stimuli and nutritional status and
maximize an individual's ability to perform ADLs. The ability to perform ADLs largely requires the physiological capacity to adapt to the upright position and to move against gravity; these are both central components of functional performance.
The basis for these goals is fourfold. First, the older adult will be able to perform self-care and be functionally independent. Second, this level of physical performance will avoid the negative consequences of restricted mobility and is consistent with health promotion. Third, should the older adult be exposed to a period of relative inactivity or become ill, a greater initial functional capacity provides a greater margin of safety. Detraining effects will be minimized and recovery hastened. Fourth, irrespective of whether the older adult has a health condition, health-related quality of life can increase proportionally with number of healthy living practices adhered to, including regular physical activity and exercise (Blanchard, Courneya, & Stein, 2008). Research is needed to elucidate the clinical reasoning process for determining the level of functional performance that is needed by a given older person to minimize morbidity and mortality, maximize health-related quality of life, and to elucidate the parameters of an exercise prescription that would best achieve these outcomes in the short and long term.
Whether the focus is directed toward functional performance, functional capacity, or both, rehabilitation is based on a detailed analysis of the factors that contribute to functional impairment of the older adult, which may reflect nutritional deficits. A nutritionist may need to be consulted; however, the occupational and physical therapist need to be familiar with basic nutritional requirements across the life span and assess nutritional adequacy at a basic level, making general recommendations related to nutrition, weight loss, or both.
The rationale for improving an older adult's ability to perform ADLs and functional capacity appears inherently reasonable. However, the goal of enhancing functional capacity in an older adult with cardiopulmonary or cardiovascular dysfunction may appear paradoxical and warrants some discussion. Given that the purposes of the cardiopulmonary and cardiovascular systems are oxygen transport and gas exchange, and that these functions are effected through an integrated system of steps along the oxygen transport pathway, it becomes clear that augmenting the function and efficiency of the steps in the pathway can enhance oxygen transport overall. The net result of improved efficiency of various steps in the pathway is improved maximum functional capacity.
Individuals with severe cardiopulmonary and cardiovascular dysfunction who cannot achieve an intensity of exercise that is sufficient to stimulate improved aerobic capacity can improve their functional capacity through other mechanisms, including desensitization to shortness of breath, increased motivation, and improved movement efficiency. Endurance is a primary objective with respect to optimizing function in the older person. Although muscle strength, balance, and coordination are also central to function, these features can frequently be optimized commensurate with endurance activities and exercise. The principle of exercise specificity indicates that optimal adaptation results if the target activity serves as the training stimulus. Keep in mind that assessment and intervention should take into account both cardiopulmonary and musculoskeletal factors (Chapters 10 and 11).
When the desired outcome is the client's ability to maintain important daily activities, these capacities are linked, and often intervention can address them simultaneously.
To prescribe ADL or exercises for older people to maintain or enhance cardiopulmonary function, the mechanisms contributing to impaired function must be analyzed in detail. Prescribing activity and exercise for older people is as exacting as drug prescription, in that exercise is inherently risky, particularly in older age-groups, and needs to be prescribed based on clear indications. Exercise can be associated with side effects and has some contraindications. Maximizing therapeutic gain and minimizing risk is the objective and may be achieved with the application of a five-point system of analysis of function. Collectively, the contribution of these six factors is established so that the mechanisms of functional impairment are understood and ADL and exercise can be prescribed appropriately by directing the intervention at specific causes of functional impairment and within an individual's capacity thereby maximizing oxygen transport required for daily activities.
The object of the assessment is to determine the individual's ability to meet the metabolic demands of the activities or exercise of interest. Common parameters that are measured during exercise include heart rate, systolic and diastolic blood pressure, rate pressure product, and breathing frequency. Oxygen consumption can be measured using a metabolic measurement cart; however, this measure is not routinely performed. Rather, oxygen consumption is estimated based on tables, provided that the work rate or work performed can be accurately determined. Other responses that need to be monitored will depend on the specific individual and the particular factors such as deconditioning that contribute to functional deficit. Although the availability and sophistication of monitoring equipment has increased, the rehabilitation professional needs to determine what measures are of particular interest, clinically relevant, and meet the requirements of being valid and reliable. Because exercise testing is an exacting procedure and must be methodically executed to be meaningful, the rehabilitation professional must standardize and appropriately record the pretest, testing, and posttest conditions of the exercise test. The details of the specific protocol must be established and the times of work rate changes and measurement recording clearly noted so that the test can be performed in precisely the same way on another occasion or by another person, if necessary. There is greater potential for variability in performing tests of daily activities than standardized exercise tests; thus, such tests need to be strictly standardized to maintain quality control, validity, and reproducibility. At the same time, relatively simple screening mechanisms may provide guidance in identifying subsequent assessment needs. A pedometer can be useful in objectively assessing an individual's activity level. Ten thousand steps a day is consistent with an active lifestyle (Tudor-Locke & Bassett, 2004), and fewer than 5,000 steps a day is consistent with a sedentary lifestyle (Tudor-Locke, Craig, Thyfault, & Spence, 2013).
Prescription of Activities of Daily Living and Exercise
Occupational and physical therapists must consider several factors when prescribing daily activities or exercise for a given individual. First, the object of the prescription needs to be defined to enhance functional performance, functional capacity, or both. If the object is to enhance functional performance of an ADL, then activity is the focus of training. The activity must be analyzed in terms of its cardiopulmonary and cardiovascular demands, in addition to whether the individual is capable of performing the activity from a neuromuscular and movement function perspective (see Chapters 10 and 11). The body position assumed in performing an activity and the use of any assistive device can alter the metabolic demand. Although some degree of aerobic fitness is desirable in the older adult, maximal aerobic fitness is not needed to perform many daily activities and live independently. Rather, activity performance and safety are the primary considerations. Assessment of an older adult's functional capacity should be based on the demands expected in the individual's living environment. For example, distance and speed requirements in the community environment vary widely. Distances to walk at community sites frequented by older adults ranged from 16 to 677 meters on average, and the average speed required to cross the street in the time of a walk signal varied from 0.44 to 1.32 meters per second (Salbach et al., 2014). An older adult's ability to perform an ADL or exercise will also depend on such factors as the time of day, whether the individual has eaten recently, what medications the individual may be receiving, and general well-being on a given day. Also, how rested and energetic the individual feels will influence the ability to perform the activity or exercise. A low-demand activity that needs to be performed once is less demanding overall than the same or more demanding activity that has to be performed multiple times. High-demand activities can be effectively interspersed with rest periods. Even in healthy young people, this type of interval training can significantly increase the overall amount of work performed.
Two concepts applied nonspecifically in the clinic are energy conservation and pacing. Although conserving energy may be a goal, energy sparing needs to be balanced with energy expenditure to avoid the deleterious effects of inactivity and deconditioning. The pace of an activity or exercise affects the overall metabolic cost. Performing an activity too slowly, as well as too fast, can increase metabolic cost; therefore, the pace at which optimal efficiency is achieved needs to be included as a component of the prescription. Research is needed to examine the concepts of energy conservation and activity pacing so that these concepts can be prescribed on a rational basis and exploited therapeutically.
The assessment identifies ADL deficits and the type of exercise program that will improve function. The capacity of the older adult to meet the metabolic demand, however, must also be evaluated. An exercise stimulus, whether prescribed to promote adaptation to ADL or exercise, should involve no more than 60 to 70 percent of peak effort and be tolerated without undue fatigue or distress. Metabolism for daily activities requires the interplay of anaerobic and aerobic metabolic processes. Sprint-type activities demand rapid release from sources of oxygen; thus, the anaerobic system of metabolism is stimulated. Light activities and activities demanding more prolonged submaximal endurance require aerobic metabolism. A physiological steady state is achieved during aerobic exercise and is more functional than anaerobic training. Aerobic adaptation can be achieved with a maximum training intensity of 40 percent of the heart rate reserve [heart rate reserve = resting heart rate + (maximum heart rate − resting heart rate)] in older persons, whereas in young people, a minimum training intensity of 60 percent of the maximum heart rate is required. Anaerobic activities or exercise are seldom indicated for older people because these can be excessively demanding physiologically and are associated with greater risk. In addition, high levels of anaerobic capacity are not as essential in daily living compared with aerobic capacity. The recommendations for exercise for older adults by the American College of Sports Medicine are comparable to those for adults, with some important distinctions. These are outlined in Box 8-3 and are expanded on in relevant sections of this chapter and Chapter 13.
BOX 8–3 Recommendations for Physical Activity and Public Health in Older Adults
Recommendations for older adults are similar for younger adults in general with the following distinctions:
The recommended intensity of aerobic activity considers the person's aerobic fitness
Flexibility activities should be included
Neuromotor fitness is a particular focus on exercise prescription
Balance exercises should be included with a view to minimize fall risk
Physical activity promotion should be part of a comprehensive program including muscle strengthening, reduced sedentary activity, risk management as well as moderately intensive aerobic activity
The parameters of activity or exercise prescription include a warm-up, a steady state, a warm-down, and a recovery period (ACSM, 2013). Even in prescribing daily activities, these components are essential if maximal benefit is to be derived with the least risk. The warm-up and warm-down are critical in priming the cardiopulmonary, cardiovascular, and musculoskeletal systems for work and recovery, respectively. An appropriate warm-up will improve the efficiency during the steady-state portion of the prescription. Monitoring is important during all portions of the prescription, including during the warm-down and recovery. These components are needed to ensure that the physiological adjustments needed to perform work have returned to baseline conditions (e.g., the degradation of lactate and circulating catecholamines). Also, adequate warm-down and recovery reduce late-onset fatigue and soreness.
Older people, particularly those with low functional capacities, can perform large amounts of work in an interval exercise program. Interval training involves alternating either relatively high and low metabolically demanding activity or low metabolically demanding activity and rest periods. Cumulatively, an individual can perform an overall amount of work that would not be achievable if it was attempted all at once. In addition, such a schedule is considerably safer and subjectively tolerated better. Rehabilitation professionals need to exploit interval-training regimens in a systematic manner in therapeutic programs for older people.
A balance of activity and rest can also be incorporated over the course of a day to maximize function. Theoretically, judicious rest periods contribute to physiological restoration, enabling the individual to perform more work and activity over time. The prescription of rest periods warrants as much attention as the prescription of exercise, given that the negative effects of excessive rest, as well as exercise, are particularly hazardous in the older person. Rest needs to be viewed as a therapeutic intervention, and similarly, the appropriate parameters need to be selected to optimize function. Considerable research is needed to improve the prescription of rest in conjunction with activity and exercise so that its inclusion will maximize work output and minimize the deleterious effects of inactivity.
The overall success of the prescription of ADL and exercise reflects not only knowledge of exercise physiology, but also consideration of psychosocial factors. The attitudes, values, and beliefs of older persons and those of their families and peers toward them and their physical status also have a significant impact on the outcomes of the program.
Physical activity is essential to life. Physical decline related to aging has been associated with deconditioning. However, studies related to motivating older adults to be physically active are limited. One study examined this relationship in older Australians and found that primary motivating factors to be physically active included keeping healthy, liking the activity, improving physical fitness, and maintaining joint mobility (Kolt, Driver, & Giles, 2004). Research suggests that brief advice provided by a health-care professional is an effective motivator. For example, a single motivational session and 15 booster telephone calls or contacts, delivered by phone or computer, significantly increased physical activity in adults aged 55 and older over the course of 1 year and led to a higher percentage of intervention participants meeting recommended levels of physical activity compared with controls (King et al., 2007). Brief advice followed by telephone calls from a trained motivational counselor was found to be effective in increasing self-efficacy for exercise, an important element for increasing physical activity (Bennett, Young, Nail, Winters-Stone, & Hanson, 2008). Similarly, a single session with a person trained in motivational interviewing, followed by telephone calls increased exercise in previously inactive adult cancer survivors (Bennett, Lyons, Winters-Stone, Nail, & Scherer, 2007).
Special mention needs to be made of walking and strength training. Walking capacity and a certain level of strength are fundamental to many daily activities. Although walking may not be essential, it can often facilitate the performance of a variety of occupations. Exercise can improve many domains of functional fitness even among very old, previously sedentary individuals, which may in turn facilitate the performance of desired activities (Simons & Andel, 2006).
Greater attention is being placed on the affective dimension of exercise. The pleasure or sheer enjoyment factor may sustain ongoing physical activity more than the goal of being healthy or fit. Dancing is little prescribed for its therapeutic benefits, yet has many established benefits. These include improved strength, endurance, balance, and cognition. The role of listening to music alone can be stimulating and lead to a sense of overall well-being, which in turn may lead to an individual increasing his or her activity level.
Smoking is the major cause of preventable death in adults (Mokdad, Marks, Stroup, & Gerberding, 2004). Thus, smokers need to be identified, smoking cessation resources and programs need to be made available, and smoking cessation needs to be a component of management in rehabilitation programs for older people to maximize functional and long-term health outcomes. Other common health concerns that are less often addressed but warrant attention by rehabilitation professionals include sleep quality and quantity, anxiety, stress and depression (see Chapter 12). Poor sleep and mental health issues can independently affect functional capacity. Optimizing sleep or improving an older adult's mental health and resilience alone may improve functional outcomes.
INTERPROFESSIONAL PRACTICE Toward Shared Core Competencies
Although occupational therapists and physical therapists have unique competencies, health assessment and health promotion interventions including regular physical activity and exercise are core shared competencies of the two disciplines (World Federation of Occupational Therapists, 2014, 2016). These need to be practiced interprofessionally, as well as taught interprofessionally to students in their entry-level programs.
Although they may appear to be performing activities associated with low metabolic demand, many older adults will be working at loads that would be unacceptable in young people or that alternatively are not within the therapeutic threshold to elicit the maximal benefit. Given that exercise constitutes a risk and that to be therapeutic its intensity needs to be gauged, objective as well as subjective monitoring should be a standard component of assessment and therapeutic interventions. All too often, however, stringent monitoring is neglected in well older adults, or those who have health issues but are medically stable older people. The inherent risk of exercise is accentuated in older people for several reasons that add further to the need to monitor these individuals. Some older adults with no cardiac history may report ischemic leg pain at rest or during exercise. These individuals have a high probability of having cardiac involvement and require cardiac and blood pressure monitoring. Older people are prone to high blood pressure and, in general, are more apt to experience blood pressure irregularities during exercise than young people. Alternatively, some older people are prone to hypotensive episodes. Thus, judicious blood pressure monitoring is essential. Although many individuals are taking medications for heart disease and hypertension, monitoring hemodynamic status is still essential. Some medications, including those to manage blood pressure, interfere with normal hemodynamic responses to exercise, in which case other parameters need to be used. Special provision needs to be made for older adults with diabetes, and a sugar source must be available in the event of a hypoglycemic episode associated with increased activity or exercise.
Safety issues are a foremost concern when testing and prescribing ADL and exercise. An activity or exercise is prescribed within the anticipated upper limit of an older adult's physiological capacity, yet above the lower limit of the therapeutic threshold range, and appropriate monitoring is conducted to verify this. A thorough knowledge of signs and symptoms of distress during exercise is essential, and these signs need to be anticipated and taught to an older person when self-monitoring is appropriate. In addition, older people are at risk of falls and fractures; thus, risks need to be identified and addressed to maximize the older adult's safety during exercise (Gillespie et al., 2012). Occupational and physical therapists involved with prescribing activity or formal exercise for any population must have current certification in cardiopulmonary resuscitation. Settings in which well older adults are provided with fitness interventions should have a procedure outlined in the event of emergencies, and appropriate equipment and facilities in the case of a respiratory or cardiac arrest. All members of the department need to be reacquainted with emergency procedures on a regular basis.
Customizing the Environment to Maximize Function
An astronaut living and working in space is not considered disabled. Modifications with respect to bathing, toileting, washing, exercising, and working have been made to enable the astronaut to survive and to be functionally independent in space. For older people, too, the physical environment can be optimized to promote function and independence as the individual continues to age and to maximize safety. Adaptive equipment, mobility aids, and assistive devices within and outside the home need to be reevaluated. In this way, independent living is promoted, the amount of time the individual is upright and moving is maximized, and the risk of morbidity, falls, and injury is reduced. Cultural considerations are also important in that they provide the basis for each individual's lifestyle, nutrition, physical activity, and preferences related to these. The principles underlying the nutrition and physical activity and exercise icon can be qualitatively modified to meet an individual's cultural preferences. Such sensitivity and attention to cultural issues will enable each individual to adhere to the rehabilitation specialist's recommendations related to health and function. Engagement of the individual's family and social support network, and possibly community, is central to consider when designing exercise programs for older people, given a supportive environment, socially as well as physically, may be all that is required to support an active lifestyle.
The principal goals of intervention to address issues of normal-aging older adults are to maximize health, improve the ability to perform daily activities, optimize functional performance, and enhance functional capacity, the reserve of the cardiopulmonary and cardiovascular systems, and the efficiency of oxygen transport overall. These goals are central to augmenting an older person's health-related quality of life through maximizing functional capacity and independence. Such an approach raises the older adult's functional capacity above the critical functional performance threshold so that with progressive aging and in the event of illness or restricted mobility, there is sufficient reserve to minimize functional deterioration and dependency. Most of what has been associated with age-related function loss can be attributed significantly to inactivity, disuse, and deconditioning.
Occupational and physical therapists must have a high level of expertise in the assessment and prescription of activity-based conditioning and exercise. Such expertise is based on knowledge of the following:
An understanding of the determinants of health, including optimal nutrition and physical activity, abstinence from smoking, quality sleep and rest, and managing stress
An understanding of the ICF, including contextual factors and their impact on health and well-being (personal and environment factors)
Healthy age-related changes in the cardiopulmonary and cardiovascular systems in addition to multiple other systems that work in an integrated manner to effect functional performance and enhance functional capacity with training
Effects of nutritional status and weight on health and functional capacity
Exercise physiology in health, the principles of adaptation to activity and exercise in older people, and the basis for activity or exercise prescription in this population
Environmental factors that can be modified to augment functional capacity and quality of life
Occupational and physical therapists are in a unique position to maximize functional performance and functional capacity in the older adult based on evidence and to identify areas that warrant additional study. Moreover, on the basis of a thorough knowledge of exercise physiology in health and health conditions, rehabilitation professionals have a responsibility to advise other health-care professionals in the promotion of activity and exercise in the older population from both a therapeutic and a lifestyle perspective.
James Hampton is an African American man who is 72 years of age. He has worked in construction most of his life and now works part time as an office cleaner. Since he retired from construction, he has been generally inactive and socially disengaged other than attending church a couple of times a month. He lives with his wife and has no medical conditions.
Describe the impact of age-related changes in cardiopulmonary and cardiovascular function on Mr. Hampton's health status. Might his race/culture affect his health risks?
Prioritize the goals of an exercise prescription and provide the rationale, including how you would engage Mr. Hampton in the goal setting.
What are some important precautions to help Mr. Hampton avoid injury as he increases his physical activity.
Critical Thinking Questions
Describe the interrelationships among structure and function, activity, and participation for older adults with respect to the cardiopulmonary and cardiovascular systems (World Health Organization International Classification of Function).
Explain why the relationships among structure and function, activity, and participation with respect to the cardiopulmonary and cardiovascular systems are often limited in older adults.
Compare and contrast changes in cardiopulmonary and cardiovascular function that you would expect to see in older adults.
Describe changes in cardiopulmonary and cardiovascular function secondary to an older adult's personal factors, such as age, sex, culture, lifestyle, nutritional status, leisure, physical activity, and long-term occupation.
Describe the comprehensive skill set related to health behavior change needed by contemporary rehabilitation professionals working with older adults.
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