Because exercise helps use up oxygen, it causes your body to burn stored fat and helps you maintain a normal weight. For instance, if you walk 4 miles a day four times a week, you can burn about 1,600 calories or nearly half a pound a week. If you don't change your diet at all and keep walking the same distance over six months, you'll lose 12 pounds. Walk the same distance for a year and you'll drop 24 pounds.
Whether we’re fully conscious of it or not, we’re always looking for how to be happy. And exercise is one of the most obvious steps to take, as it’s not a coincidence that you feel better after a good workout: It’s science. A Penn State University study found that people who exercised, whether it was a mild, moderate or vigorous workout, had more pleasant feelings than those who didn’t. (1)