New research says you can burn up to 200 calories in just 2 and a half minutes of super hard, concentrated effort a day. Try this high-intensity workout: Pedal as fast as possible (100-percent effort) on a stationary bicycle set at a high resistance for 30 seconds. Then lower the resistance and pedal slowly for 4 minutes. Repeat this sprint-and-recover set five times total. You'll be at it for at least 25 minutes, but that's a helluva lot shorter and more effective than 45 minutes at the same moderate pace on the elliptical machine or treadmill. Source: American Physiological Society
