The Fastest Cardio Workouts Ever

Use these high-voltage routines to burn away belly flab and finally reveal your abs.

By Alwyn Cosgrove, C.S.C.S., Men's Health

It's a universal law of fitness: The less time you have, the easier it is to find excuses to skip a cardio workout. After all, doesn't a good routine require at least 30 minutes?

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.

The workouts

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.

Do one 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.)

Squat series

Repeat the series twice without any rest, for a total of three rounds.

1. Body-weight jump squat: Lower your body until your thighs parallel the floor. Then jump as high as you can. Repeat for 20 seconds.

2. Body-weight squat: Do as many reps as you can in 20 seconds.

3. Isometric squat: Lower your body until your thighs parallel the floor, and pause. Hold the position 30 seconds.

Don't ignore your legs—building them boosts your metabolism by increasing your body's lean muscle mass. Learn 40 small changes that lead to bigger muscles all over.

Countdown (choose option 1 or 2)

Alternate between the two exercises without resting. For your first round, do 10 repetitions of each exercise. For your second round, do nine reps. Then do eight reps for your third round, and so on. Go as low as you can, or until you reach zero. Each week, raise your starting rep count by one—so if you did reach zero, you'll start with 11 repetitions for the second week.

Option 1

1. Single-arm dumbbell swing: Using an overhand grip, hold a dumbbell at arm's length in front of your waist. Bend at your hips and knees and lower your torso until it's at a 45-degree angle to the floor. Swing the dumbbell between your legs, and then thrust your hips forward and swing the dumbbell up to chest level as you stand. Reverse the move, and repeat.

2. Squat thrust: Stand with your feet shoulder-width apart and your arms at your sides. Push your hips back, bend your knees, and lower your body as deep as you can into a squat. Now kick your legs backward so that you're in a pushup position. Then quickly bring your legs back to a squat. Stand up quickly and repeat the entire move.

Option 2

1 Body-weight jump squat

2. Explosive pushup: Assume a pushup position, your hands slightly beyond shoulder width. Your body should form a straight line from your ankles to your head. Bend your elbows and lower your body until your chest nearly touches the floor. Press yourself up with enough force that your hands leave the floor.

And be sure to check out the 4-week workout to boost your muscle, health, and sexual vitality.