Boost your energy...all you need is 15 minutes

Here's another reason to get moving: Working out really does put pep in your step, says a recent study in the Journal of Sport and Exercise Psychology. It found active people also tend to be more excited and enthusiastic. Researchers asked 190 university students to keep diaries of their physical activity and sleep, as well as their mental states and stress levels. They found that participants who were more active were happier—and they were even more joyful on days when they were more active than usual.

Bottom line: Get up and get moving—it's worth the extra effort. At least 15 minutes of moderate to vigorous physical activity a day will get those feel-good endorphins pumping.