Importance of Exercise and Physical Activity in Older Adults Reviewed

From Medscape Medical News CME

Laurie Barclay, Désirée Lie,

July 8, 2009 — The American College of Sports Medicine has issued a position stand providing an overview of issues critical to understanding the importance of exercise and physical activity in older adult populations. The review and guidelines are published in the July issue of Medicine & Science in Sports & Exercise.

"The 2008 Physical Activity Guidelines for Americans affirms that regular physical activity reduces the risk of many adverse health outcomes," write Wojtek J. Chodzko-Zajko, PhD, and colleagues from the American College of Sports Medicine. "The guidelines state that all adults should avoid inactivity, that some physical activity is better than none, and that adults who participate in any amount of physical activity gain some health benefits. However, the guidelines emphasize that for most health outcomes, additional benefits occur as the amount of physical activity increases through higher intensity, greater frequency, and/or longer duration."

The reviewers conclude that no amount of physical activity can stop biological aging but that evidence to date affirms that by limiting the development and progression of chronic disease and disabling conditions, regular exercise can reduce the physiologic harms of an otherwise sedentary lifestyle and improve active life expectancy. Older adults who engage in regular exercise may also experience significant psychological and cognitive benefits.

The position stand recommends that all older adults participate in regular physical activity and avoid an inactive lifestyle and that exercise prescription for older adults include aerobic, muscle-strengthening, and flexibility exercises

Benefits of Physical Activity and Exercise

The following are some specific evidence statements regarding the benefits of physical activity and exercise, and their accompanying level of evidence rating(see "Note" at end of article for explanation of the ratings):

Vigorous, long-term participation in aerobic exercise training (AET) improves cardiovascular reserve and skeletal muscle adaptations, allowing trained older persons to sustain a submaximal exercise load with less cardiovascular stress and muscular fatigue than their untrained peers. Prolonged AET may also reduce age-related accumulation of central body fat, thereby protecting the heart (level of evidence, B).

Prolonged participation in resistance exercise training (RET) increases muscle and bone mass and strength to a greater extent vs AET (level of evidence, B).

In healthy middle-aged and older adults, AET programs of sufficiently intense (≥ 60% of pretraining VO2max), frequency, and length (≥ 3 days/week for ≥ 16 weeks) may significantly improve VO2max (level of evidence, A).

In healthy middle-aged and older adults, 3 months or more of moderate-intensity AET are associated with cardiovascular adaptations which are apparent both at rest and in response to acute dynamic exercise (level of evidence, A/B).

Moderate-intensity AET has been shown to reduce total body fat, but not fat-free mass, in overweight middle-aged and older adults (level of evidence, A/B).

Beneficial metabolic changes associated with AET include improved glycemic control and clearance of postprandial lipids, as well as preferential utilization of fat during submaximal exercise (level of evidence, B).

In postmenopausal women, AET may counteract age-related decreases in bone mineral density (level of evidence, B).

RET may markedly increase strength and muscular power in older adults (level of evidence, A).

Older and younger adults have similar age-related increases in muscle quality, and these increases do not appear to be sex specific (level of evidence, B).

Improvements in muscular endurance have been reported after RET using moderate- to higher-intensity protocols, but not lower-intensity RET, and may improve muscular endurance (level of evidence, C).

Although the effect of exercise on physical function is poorly understood and may not be linear, RET may improve walking, chair stand, and balance activities (level of evidence, C/D).

Older adults who regularly take part in moderate- or high-intensity RET may have increased fat-free mass, decreased total body fat mass, and other beneficial changes in body composition (level of evidence, B/C).

Compared with sedentary control subjects, adults who participate in high-intensity RET have maintained or improved bone mineral density, with a direct relationship between muscle and bone adaptations (level of evidence, B).

Evidence is mixed regarding the effect of RET on metabolic variables (level of evidence, B/C).

In populations at increased risk of falling, multimodal exercise, including strength and balance exercises, and tai chi may decrease the risk for noninjurious and sometimes injurious falls (level of evidence, C).

Few controlled studies have evaluated the effect of flexibility exercise on range of motion in older adults (level of evidence, D).

Regular exercise and physical activity are linked to significant improvements in overall psychological well-being, possibly via effects on self-concept and self-esteem. Physical fitness and AET are linked to a lower risk for clinical depression or anxiety (level of evidence, A/B).

Cardiovascular fitness and higher levels of physical activity lower the risk for cognitive decline and dementia, based on epidemiologic studies. In experimental studies, AET and RET, alone or especially combined, improve some measures of cognitive functioning, especially those requiring executive control, in previously sedentary older adults (level of evidence, A/B).

Physical activity appears to be linked to some aspects of quality of life, but the precise nature of the relationship is unclear (level of evidence, D).

High-intensity RET is effective for treating clinical depression. Additional research should address the optimal intensity and frequency of RET needed to elicit specific improvements in other measures of psychological health and well-being (level of evidence, A/B).

"A combination of AET and RET activities seems to be more effective than either form of training alone in counteracting the detrimental effects of a sedentary lifestyle on the health and functioning of the cardiovascular system and skeletal muscles," the authors of the position stand conclude. "Although there are clear fitness, metabolic, and performance benefits associated with higher-intensity exercise training programs in healthy older adults, it is now evident that such programs do not need to be of high intensity to reduce the risks of developing chronic cardiovascular and metabolic disease. However, the outcome of treatment of some established diseases and geriatric syndromes is more effective with higher-intensity exercise (e.g., type 2 diabetes, clinical depression, osteopenia, sarcopenia, muscle weakness)."

Med Sci Sports Exerc. 2009;41:1510-1530.