No, actually, it doesn't. I've found that clients at my gym achieve the fastest results with the shortest cardio workouts. It's basic exercise science: The harder you go, the more calories you burn every minute. And unlike slow-and-steady running, cardio at a fast, furious pace can speed your metabolism for hours after your workout. So you lose lard even while you're sleeping. What's more, research shows that brief, intense bouts of exercise can improve your cardiovascular fitness as much as jogging can.
These circuit workouts, from the Big Book of Exercises, can be performed in your basement, and they're as challenging as a series of gut-wrenching sprints. Try one, and you'll never again think "running" when you hear the term "cardio." The bonus? Faster workouts leave you with fewer excuses.
Perform any of these quickie cardio routines at the end of your typical weight session. They're called "finishers," not just because doing them is a great way to finish off an exercise session, but also because they can help you finish off your fat. For a longer routine to melt your gut and chisel a six-pack, try the Trade Your Belly for Biceps workout.
The Leg Matrix
Do 1 set of each exercise without resting, and keep track of the time it takes you to complete the circuit. Rest for double that time, and then repeat the circuit. When you can finish the first circuit in 90 seconds, skip the rest period.
1. Body-Weight Squat: 36 reps
2. Body-Weight Alternating Lunge: 18 each leg
3. Body-Weight Split Jump: 18 each leg
4. Body-Weight Jump Squat: 36 reps. (For instructions, see squat series below.)