Build Muscle

A seven-week study of 22 couch potatoes found that those who did just one set of 10 repetitions of seven strength-training moves (about 10 minutes of lifting) three days a week gained as much strength as those who did a 30-minute, three-set routine.

Boost your mood

In a recent study of 48 men and women, spinning on a bike for 10 minutes led to a mood lift and drop in depression and fatigue—similar to what they'd get riding three times as long.

Protect your joints

After tracking nearly 4,000 women in their 70s for three years, researchers found that those who reported of having arthritis pain needed only 75 minutes a week of moderate exercise like brisk walking to reduce the frequency of symptoms by nearly 30 percent.

Manage your weight

Both Church's study and a larger study of 13,711 men and women reveal that just 70 to 75 minutes of brisk walking or about 40 minutes of jogging a week is enough to begin shrinking your waistline. And targeting the waist is important because belly fat is directly tied to heart disease, diabetes, and early death.

Quell stress

"We've seen significant changes in the autonomic nervous system—fewer incidences of the fight-or-flight stress reflex being triggered—with even 70 to 75 minutes a week of exercise," says Church. "A little exercise can do much more than people think, so there's no excuse for not getting up and just doing something."

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