7 Easy Ways to Kick-Start Your Metabolism
Cyclists who pedaled at an all-out effort with high resistance for a total of five 30-second sprints (that's just 2.5 minutes!) burned a whopping 200 calories, according to recent Colorado State University research.
Don't forget to recover between intervals: Here participants recouped with four minutes of slow pedaling with low resistance after each burst.
"Changing the intensity forces your muscles to work harder," says Andia Winslow, a personal trainer in New York City.
Next: Guzzle H20