Lack of sufficient physical activity is the second most important contributor to preventable deaths, trailing only tobacco use. A sedentary lifestyle has been linked to 28% of deaths from leading chronic diseases. Sedentary behavior and physical inactivity have also been linked to decreases in midlife cognition. Worldwide, approximately 30% of adults are physically inactive. Inactivity rates are higher in women, in those from high-income countries (such as the Americas), and in aged individuals. Alarmingly, among teens aged 13–15, 80% report doing less than 60 minutes of physical activity of moderate to vigorous intensity per day; boys are more active than girls.
The US Department of Health and Human Services and the CDC recommend that adults (including older adults) engage in 150 minutes of moderate-intensity (such as brisk walking) or 75 minutes of vigorous-intensity (such as jogging or running) aerobic activity or an equivalent mix of moderate- and vigorous-intensity aerobic activity each week. In addition to activity recommendations, the CDC recommends activities to strengthen all major muscle groups (abdomen, arms, back, chest, hips, legs, and shoulders) at least twice a week.
Patients who engage in regular moderate to vigorous exercise have a lower risk of myocardial infarction, stroke, hypertension, hyperlipidemia, type 2 diabetes mellitus, diverticular disease, and osteoporosis. Evidence supports the recommended guidelines of 30 minutes of moderate physical activity on most days of the week in both the primary and secondary prevention of CHD.
In older nonsmoking men, walking 2 miles or more per day is associated with an almost 50% lower age-related mortality. Diet and increased physical activity have been shown to prevent the onset of diabetes mellitus, which has reached epidemic proportions in the United States. In sedentary individuals with dyslipidemia, high amounts of high-intensity exercise produce significant beneficial effects on serum lipoprotein profiles. Physical activity is associated with a lower risk of colon cancer (although not rectal cancer) in men and women and of breast and reproductive organ cancer in women. Finally, weight-bearing exercise (especially resistance and high-impact activities) increases bone mineral content and retards development of osteoporosis in women and contributes to a reduced risk of falls in older persons. Resistance training has been shown to enhance muscular strength, functional capacity, and quality of life in men and women with and without CHD and is endorsed by the American Heart Association.
Exercise may also confer benefits on those with chronic illness. Men and women with chronic symptomatic osteoarthritis of one or both knees benefited from a supervised walking program, with improved self-reported functional status and decreased pain and use of pain medication. Exercise produces sustained lowering of both systolic and diastolic blood pressure in patients with mild hypertension. Physical activity reduces depression and anxiety; improves adaptation to stress; improves sleep quality; and enhances mood, self-esteem, and overall performance.
In longitudinal cohort studies, individuals who report higher levels of leisure-time physical activity are less likely to gain weight. Conversely, ...