Hypothyroidism

Overview of Hypothyroidism

Hypothyroidism is a deficiency of thyroid hormones, due primarily to decreased synthesis or size of the thyroid gland. A deficiency of thyroid hormones affects multiple systems, which can result in slower metabolism, muscle weakness, advanced atherosclerosis, and slower mental functions. Individuals may have a subclinical hypothyroidism even though their thyroid hormone levels are within normal value limits.¹ This condition is reversed with administration of synthetic thyroid hormones. Decreased thyroid hormone levels affect connective tissues of the cardiovascular system, resulting in decreased cardiac output, slowed heart rate, and diminished peripheral circulation.^1,2 Proximal muscle weakness along with complaints of stiffness, muscle pain, and trigger points make daily activities more difficult to complete.

Systemic Manifestations That Affect Exercise Tolerance

Central nervous system: Fatigue and headaches

Cardiovascular system: Heart failure, angina, poor peripheral circulation, dyspnea

Musculoskeletal system: Proximal muscle weakness, myalgia, joint swelling

Gastrointestinal system: Weight gain, decreased absorption of nutrients

Comorbidities to Consider

• Long-term use of synthetic thyroid hormones may lead to limited cardiac functions and exercise tolerances.³

Client Examination

Keys to Examination of Clients

• Ask clients about their laboratory tests for their levels of thyroid-stimulating hormones and thyroxine (T₄). Hypothyroidism can significantly elevate serum cholesterol and triglyceride levels.

• Take vital signs, and look for signs of congestive heart failure as clients recently diagnosed with this condition may have atherosclerosis with or without angina. Administration of synthetic hormones increases heart muscle activity, which may aggravate angina symptoms.

Recommended Baseline Testing of Fitness Levels

• Tests of aerobic fitness and muscle strength should begin with very low levels of exertion, with monitoring of clients' symptoms and tolerance to the activities.

• Screen clients for their preparedness to begin an exercise program.

Exercise Prescription

Type: Walking, cycling

Intensity: Low levels; start at 50% of maximum heart rate

Duration: Short bouts, with regular vital sign assessments

Frequency: Five to seven times per week

Getting Started

Aerobic exercises should be chosen to allow long-term adoption of an independent exercise program. Interventions to address myalgia and trigger points may be needed before beginning a regular exercise program. Clients with severe muscle and joint pain may only tolerate interventions to regain motion and increase activity levels. Exercise-induced muscle pain may be a precursor to rhabdomyolysis, which will result in further muscle damage and renal failure. Strengthening activities should also be started at low level of intensities, with an emphasis of higher repetitions (15 to 20) and performing motions through full ranges and proper form. Gradual progression of exercise programs allows clients to ...