Even a little exercise can help keep your ticker strong, studies suggest. For example, research published in the  American Journal of Hypertension found that 61 to 90 minutes of exercise a week was more effective at lowering systolic blood pressure (the top number) than 30 to 60 minutes a week. But exercising for more than 90 minutes a week didn't have an increased benefit when it came to lowering  blood pressure or the heart risks associated with it. And a new study published in  The Lancet found that heart patients who met the guidelines of at least 30 minutes of moderate exercise five times a week saved $2,500 in  healthcare costs compared to those who didn't, suggesting exercise helped stave off complications.

Exercise  has been found to lower the risk of breast, colon, and endometrial cancers, and the American Cancer Society recommends 150 minutes of moderate-intensity physical activity per week, or 75 minutes of vigorous-intensity activity, to lower overall  cancer risk. One study from the  Breast Cancer Research and Treatment journal found that for every hour per week spent running at a 10-minute mile pace-or every four hours per week spent walking at a 30-minute mile pace-breast cancer risk decreased by 3%.

All it takes is a quick sweat session after a long day to notice how exercise seems to melt  stress away. And of all the health benefits, that's one that can be achieved almost instantly, says Phillips.

"The thing that gets people to exercise and sustains them is not saying, 'Oh my gosh, I have to exercise because I need to [prevent  disease],' but because it feels good," he says. "It's the immediate feedback that compels people, and one of the most immediate things people report is that their stress levels are reduced when they exercise."

Beyond day-to-day stress, exercise can help relieve depression symptoms, too. In one study published by the  American Journal of Preventative Medicine, women who were experiencing depression who completed 200 minutes of walking a week (or 150 minutes of moderate-intensity exercise) had improved mental health, social functioning, physical health, and vitality over time. Other research from the  Harvard Special Health Report discovered that walking briskly for 35 minutes a day, fives time a week (or 60 minutes, three times a week) can significantly improve mild to moderate  depression, while walking only 15 minutes a day, five times a week, or stretching three times a week are less effective.