Doing intervals of intense training for as little as six minutes can do more for your fitness levels than cardio workouts that last as long as 45-60 minutes, according to research from McMaster University in Canada. Those who did four to seven 30 second bursts of "all-out" exercise, followed by four minutes of recovery time, three times a week for two weeks, significantly increased their endurace capacity over those who did traditional cardio training.
"Overall, 1.5 hours a week (including rest periods) of intense interval bursts equaled the results of 4.5 hours of regular training."
