Researchers reviewed eight studies that used accelerometers to follow 36,383 adults, 40 years of age and older, for six years (Brit Med J, August 21, 2019). They found that exercising regularly, regardless of intensity, was associated with reduced risk for death during the study period, while sitting for more than nine hours a day was associated with increased risk of death.

The death rate dropped progressively as light physical activity increased up to five hours per day and moderate activity increased up to 24 minutes per day. Examples of light intensity included walking slowly, cooking and washing dishes. Moderate activity included brisk walking, vacuuming or mowing the lawn, while vigorous activity included jogging or carrying a heavy load. In another study, lack of physical activity doubled a person’s chances of suffering a heart attack, while a regular exercise program helped prevent it (Eur Heart J, 15 January 2019).

Not exercising regularly worsens diabetes (Cardiopulmonary Phys Ther J, 2013 Jun;24(2):27–34). Most cases of diabetes are caused primarily by excess fat in the liver and muscles, the only two places humans can store significant amounts of sugar. Excess fat in muscles and liver prevent these tissues from clearing excess sugar from the bloodstream. Most cases of diabetes can be cured by getting excess fat out of the liver, and the longer you exercise, the more fat you remove from muscles and liver and the less likely your blood sugar is to rise too high after you eat (Curr Cardiol Rep, Dec 2016;18(12):117).

Intense Exercise is Beneficial
Richard A. Winett of Virginia Tech has reviewed 106 journal articles to show that intense exercise can benefit health, prevent disease and prolong lives (Innovation in Aging, July 26, 2019;3(4):1–15). If you are trying to lose weight, intense interval exercise may help you to lose more weight than slower continuous exercise (Brit Med J, Feb 14, 2019). If you exercise intensely, you don't have to spend as much time exercising to gain the same health benefits (J Am Coll Card, June 21, 2016;67(24):2910-2911).

A review of 41 studies involving 1115 people showed that people who have limited time to exercise will gain more health benefits from short bursts of intense exercise with short rests between each interval compared to continuous training (Brit J Sports Med, Feb 14, 2019;53(10)). Ideal sports for interval training include running, fast walking, cycling, swimming and weight lifting, but intense exercise can increase risk of injuries. Everyday opportunities for interval exercise include carrying heavy shopping bags up a few flights of stairs, running to catch a bus, walking fast from one place to another, pushing a lawn mower, or vacuuming your house with vigor.

My Recommendations
A key to prolonging your life and preventing disease is to keep on moving. Lying in bed for many hours each day is a certain way eventually to kill yourself. Your skeletal muscles circulate blood to your heart, and when you contract a muscle, it squeezes blood vessels near it to pump increased amounts of blood back to your heart. Your heart responds to the extra blood by contracting with greater force that makes it stronger. Each day that you spend not moving your muscles weakens your heart until you eventually die of heart failure.

Exercise will prolong your life. You do not have to have a specific exercise program, but you should keep on moving for a large part of each day. It is healthful to mow your lawn, wash your dishes, make your bed, vacuum your house, go out for walks and participate with your friends in activities in which you are moving your arms and legs. I recommend participating in groups for dancing, cycling, swimming, running, nature walks and so forth.