Good night's sleep

An active lifestyle might also mean a more restful sleep. The National Sleep Foundation reports that exercise in the afternoon can help deepen shut-eye and cut the time it takes for you to fall into dreamland. But, they caution, vigorous exercise leading up to bedtime can actually have the reverse effects.

A 2003 study, however, found that a morning fitness regime was key to a better snooze. Researchers at the Fred Hutchinson Cancer Research Center concluded that postmenopausal women who exercised 30 minutes every morning had less trouble falling asleep than those who were less active. The women who worked out in the evening hours saw little or no improvement in their sleep patterns.

No studies have proven conclusively the best time to exercise, says Comana, but the benefits of "a better ability to fall asleep and a more restful sleep when you do -; there's unanimous agreement on that."

A stop to smoking

The adrenaline rush and stress relief from a brief workout can replace similar feelings smokers get from tobacco and help reduce the urge for a cigarette for those trying to quit, according to smoking cessation programs.

Interested in the effect of exercise on someone trying to kick the habit, one study in the Archives of Internal Medicine followed 281 sedentary female smokers, who were otherwise healthy, in their efforts to quit. The group assigned exercise sessions was twice as likely to quit and stay smoke-free over the nonexercise group, both at 12 weeks and a year later.

Brain boost

Regular exercisers may have to work less to jog their memory in the long run, as well as experience short-term benefits in creativity and reaction time.

One study in the journal Nature reports that sedentary senior citizens who took up walking for 45 minutes, three days a week, were able to significantly improve mental skills that decline with age. Meanwhile, Middlesex University researchers in London discovered that 25 minutes of aerobic exercise boosted scores on creativity tests that followed.

And one study "found physically fit workers were 12.5 percent more efficient at the end of the day than their nonphysically fit counterparts," Comana says.

Better sex

If a well-rested, smarter and nonsmoking self is not enough, exercise has also been linked to a better sex life. Poor general health can lead to poor sexual function, so keeping fit only helps maintain or revitalize performance and satisfaction in the bedroom.

After studying more than 31,000 men, the Harvard School of Public Health researchers reported that those who were physically active had a 30 percent lower risk for erectile dysfunction than the men with little or no physical activity.

Women reap the exercise benefits, too. One study by the University of British Columbia found that 20 minutes of exercise spurred greater sexual response in the women participants compared with no exercise at all.

And overall, people who exercise regularly feel better about themselves, feel more sexually desirable and report higher levels of satisfaction, according to a study in the Electronic Journal of Human Sexuality.

Along with these lesser-known benefits, exercise also promotes health in a myriad of tiny detailed ways, says Comana, with increased "coordination, flexibility and greater efficiency in daily activities."