Another study by Tabata and colleagues from National Institute of Fitness and Sports, Kagoshima Prefecture, Japan reveals that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly. In short, quick bursts of increased physical activity may be more or at least as effective for fitness and weight loss as upto an hour of slow consistent exercise without intermittent spurts of increased heart rate inducing sprints.
http://www.wsj.com/…/why-a-few-minutes-of-exercise-can-show…