According to the 2008 Physical Activity Guidelines for Americans, adults need at least 2.5 hours of moderate-intensity aerobic exercise a week, as well as two or more sessions of muscle strengthening activities.
However, a large share of Americans do not exercise at all outside of getting up and going to work, and that share has been growing. Today, 23.0% of the U.S. adult population lives a sedentary lifestyle. In the Boston-Cambridge-Newton metro area, 20.9% of adults report no leisure-time physical activity, lower than the inactivity rate for Massachusetts as a whole and lower than the national figure.
In addition to rising physical inactivity during off hours, Americans are getting less exercise at work. A recent study found that while half of all jobs in 1960 required moderate physical activity, just 1 in 5 jobs today do. Rising inactivity both at home and in the workplace has contributed to the country’s obesity epidemic. Since 1990, the national obesity rate has more than doubled to 27.0% of the U.S. adult population. In Boston, 22.9% of adults are obese, lower than the 23.7% statewide obesity rate and lower than the national figure.
Residents of poor, rural neighborhoods are often more likely to lead sedentary lifestyles than middle- or high-income Americans. One study found that residents of households earning less than $15,000 annually are three times more likely to be physically inactive than those of households earning incomes of more than $50,000 annually. An estimated 5.7% of all Boston households earn less than $10,000 annually, a smaller share than the 7.2% of American households with incomes below $10,000. The typical household in Boston earns $78,800 a year, roughly $23,000 higher than the national median household income.
A fairly dense city, 94.7% of households in Boston are in urban neighborhoods. This may be one reason for the a large share of metro area residents with adequate access to places for physical activity. At 94.9%, it is a larger share than the 84.0% of Americans with access to opportunities for exercise.
According the World Health Organization, physical inactivity is the fourth leading cause of preventable death worldwide. The WHO estimates that 3.2 million deaths worldwide are due to physical inactivity. Places with large shares of sedentary residents are likely to have a high incidence of premature death. For every 100,000 residents of Boston, 80.5 die before the age of 75, higher than the premature death incidence nationwide of 78.5 deaths per 100,000 Americans.
Physical inactivity increases the risk of noncommunicable disease such as cancer, diabetes, and cardiovascular disease. Nationwide, 9.3% of adults have diabetes, and 448 Americans out of every 100,000 have been diagnosed with some form of cancer. In Boston, 8.9% of adults have diabetes and 481 of every 100,000 residents has cancer.