"I don't have time." It's the standard excuse we give when we don't want to work out. And it's believable, too. After all, we're very busy people who are constantly multitasking everything from careers to families to social lives. We know that exercising is crucial to our health, but we've been taught that we need to devote at least 30 minutes to cardio each day in order to adequately rev our heart rate and reap any serious benefits. Who has that kind of time? As it turns out, everybody.

Recent research reveals that performing 6 30-second sprints, with a rest in between, for a total of just 3 minutes of high intensity exercise will boost your metabolism. The study involved 16 otherwise inactive males who were asked to perform a series of sprints on stationary bikes at their maximum intensity levels. Results confirmed that quick bursts of vigorous exercise, lasting only about 30 seconds each, improve metabolism and insulin action, and lower the risks for heart disease and diabetes.