Strengthen your heart
While any form of exercise provides a wealth of health perks, high-intensity interval training (HIIT) is optimal for keeping your ticker strong. Compared to moderate exercise, HIIT is better at reversing risk factors that contribute to metabolic syndrome—a combination of high blood pressure and cholesterol, abdominal obesity, and insulin resistance that increases your odds of a heart attack or diabetes.
In research comparing three styles of exercise—steady state, intervals, and an uphill bout to exhaustion—intervals boosted mood the most, inducing a sense of well-being and reducing stress. The reason may be that the periods of less intense activity that follow endorphin-producing intense exercise provide not only a physical break but a psychological one as well, explains Michele Olson, a professor of exercise science at the Human Performance Laboratory at Auburn University in Montgomery, Georgia, who conducted the study.
Get in shape faster
HIIT whips you into shape faster than other kinds of cardio by boosting your "VO2 max," the maximum amount of oxygen you use during high-intensity exertion and a measure of your cardiovascular fitness. "People with high levels of VO2 max use oxygen more efficiently so they can work out longer and harder before tiring out," explains Wayne Westcott, fitness research director at the South Shore YMCA in Quincy, Massachusetts.