LOS ANGELES -- Don't despair if you can't fit in the recommended 30 minutes of daily exercise. Growing evidence suggests that even half that much can help.
It's still no excuse to slack off. Regular exercise -- including brisk walking, bike riding and water aerobics -- strengthens muscles, reduces the risk of some diseases and promotes mental well-being. The more exercise, the better.
But not everyone has the time or willpower. So researchers set out to find the minimum amount of physical activity needed to reap health benefits. The findings by a study in Taiwan suggest that 15 minutes of moderate exercise a day can lengthen life.
This "may convince many individuals that they are able to incorporate physical activity into their busy lives," Dr. Anil Nigam of the University of Montreal said in an e-mail.
The study, a large one led by researchers at the National Health Research Institutes in Taiwan, found that those who exercised 15 minutes a day -- or 90 minutes a week -- extended their life expectancy by three years compared with those who did no exercise.