Overview of Hyperthyroidism
Hyperthyroidism results in generalized elevation of metabolism and increased activity of the sympathetic nervous system. Graves disease is the most common form of hyperthyroidism. Manifestations include weight loss, tremor, heart palpitations, sweating, and heat intolerance. This condition increases the metabolic rate and oxygen consumption, requiring an increased supply of oxygen and removal of metabolic products from the skeletal muscles.1 Hyperthyroidism may cause an over-reliance on muscle glycogen during exercise programs.2 Those who develop arthralgias secondary to this condition will greatly reduce their daily activities in order to control joint pains. Severe cases of hyperthyroidism may result in myopathy of the proximal and respiratory muscles. Treatment usually results in insufficient thyroid hormone production, requiring the client to take synthetic thyroid hormone.
Comorbidities to Consider
Keys to Examination of Clients
Clients will have undergone tests for blood levels of thyroid-stimulating hormone, thyroid hormones, and radioactive iodine uptake.
Carefully assess heart rate and blood pressure as clients may have tachycardia and abnormal systolic and diastolic blood pressures at rest and with exercise.1
Ask clients about medications they use to control the production of thyroid hormones.
Recommended Baseline Testing of Fitness Levels
Assess aerobic function by means of treadmill or cycle ergometer.
Assess strength of the proximal muscles through dynamometry and tests of one-repetition maximum.3
Determine body composition for the relationship of lean mass to total body weight.
Type: Walking; weight-training programs.
Intensity: 60%–80% of one-repetition maximum for 8–10 repetitions
Frequency: Two to three times per week
Individuals with severe hyperthyroidism need a complete resistive exercise program in order to regain normal levels of strength and muscle mass.3 Individuals with well-controlled cases can participate in exercise and recreational programs of their choice. During exercise activities the client should be regularly assessed for signs of heat intolerance, which may include excessive sweating, muscle cramping, nausea, tingling in the extremities, and syncope. After exercise, a client's heart rate may stay elevated for an extended period. Resistive exercise performed 2 days per week for 16 weeks has been found to result in significant increases in muscle strength and promote muscle mass in clients receiving treatment for hyperthyroidism.1 Clients with well-controlled conditions should be encouraged to maintain an exercise program three to five times per week for at least 30 minutes to maintain muscle strength and decrease the risk of developing heart disease.4 Clients with this condition can increase their resistive exercise program if the program does not increase their level of fatigue or ...