Ethel, your 75-year-old patient, comes into your office inquiring about starting an exercise program. Some of her friends participate in an exercise group and have been talking about the benefits of exercise. Ethel asks for your advice about starting her own exercise program. She has arthritis and hypertension, for which she takes a β-blocker; otherwise, Ethel is in good health.
General Principles in Older Adults
Physical activity has a profound positive impact on health, chronic disease prevention, function, and fall prevention, especially for older adults; higher levels of physical activity have been linked to reduced morbidity and mortality. New evidence has emerged indicating the positive impact of physical activity on cognition and psychological health. Although physical activity has clear benefits to health and function, most older adults are not physically active or do not engage in activity at high enough intensities to obtain the noted health benefits. In fact, less than 10% of older adults meet the recommended guidelines for physical activity (ie, 30–60 minutes of moderate-to-vigorous physical activity per day, 5 or more days a week), accumulating only 5–10 minutes of moderate-to-vigorous physical activity per day.
Physical activity is not synonymous with exercise. Physical activity is “any bodily movement produced by skeletal muscles that results in energy expenditure,” whereas exercise, a subset of physical activity, is “planned, structured, and repetitive bodily movement done to improve or maintain one or more components of physical fitness.” Physical activity may not achieve the increased fitness levels that are often expected with exercise; however, physical activity can reduce the risks and complications of many chronic conditions and increase well-being if it is of sufficient intensity.
Multiple methods exist to identify the level of intensity of an activity. One method compares the energy cost of the activity to the energy cost at rest, assigning metabolic equivalents, or MET values to different activities. Estimates of the MET values are summarized in the Compendium of Physical Activities, and the level of intensity of an activity is based on its MET value. However, the Compendium was developed based on data from healthy adults. Because energy use may be more inefficient in older adults, the intensity based on the MET value may underestimate the intensity at which the older adult is working. For this reason, the best use of the Compendium in the older adult population is to create a hierarchy of activities that can be used to select gradually increasing energy-demanding activities, rather than using it to define the exact intensity of an activity.
Because MET levels may not be the best method to determine the intensity of an activity, other methods should be used to estimate how hard the older adult is working, such as heart rate, rating of perceived exertion (RPE), or the talk test. Using a percentage of the estimated maximum heart rate, traditionally calculated by subtracting ...