Cardio Exercise: Maximize Muscle Burn

Make sure you have a cardio exercise plan that will give you the most bang for your muscle burn.

Whether it's pounding the pavement, logging miles on the bike, or climbing those stairs that seem to go nowhere, it's all about cardio exercise. But other than a sweaty t-shirt, what do you have to show for your workout? A slimmer stomach? Killer quads? Are you exercising for the right amount of time to reap the full health benefits of cardiovascular fitness, or often enough?

Exercise experts, including fitness maven Denise Austin, answer cardio questions for WebMD, so you can make the most of your muscle burn.

Cardio Exercise: The Heart of the Matter

"Cardiovascular exercise is any type of exercise that increases the work of the heart and lungs," says Tommy Boone, PhD, a founding member of the American Society of Exercise Physiologists. "Walking, jogging, and running are common forms of cardiovascular, or aerobic, exercise."

From running and walking, to swimming, elliptical cross-training, biking, Stairmaster, and rowing -- to name a few -- the physical benefits of cardio exercise abound, explains says Len Kravitz, PhD, senior exercise physiologist for IDEA Health and Fitness Association. They include:

Reduced risk of heart disease
Improved blood cholesterol and triglyceride levels
Improved heart function
Reduced risk of osteoporosis
Improved muscle mass 

"The American College of Sports Medicine and the CDC recommend, for health, that adults should accumulate 30 minutes of moderate-intensity physical activity on most days of the week," says Kravitz, who is also a coordinator of exercise science at the University of New Mexico. "And to improve cardiovascular endurance, they recommend 20 to 60 minutes on three to five days per week."

Now that you know the benefits of cardio exercise, where should your heart-pumping fitness plan begin?

Getting Into the Zone

To help you make the most of your cardio exercise workout -- help your heart, increase muscle, and lose fat -- Denise Austin, fitness expert, author of seven books, including Shrink Your Female Fat Zones, and star of 50 fitness videos, gives WebMD some tips.

"To reap all the benefits of a cardio workout, you should sustain your workout for 20 minutes or more -- I do 30 minutes myself -- on a schedule of about three to four times per week," says Austin.

Not only that, but you need to get in the zone, which calculates into burning calories and fat.

"The best way to find out if you are burning fat is to take your pulse halfway into your cardio workout for six seconds, then add a zero to that number," Austin tells WebMD.

This number is your heart rate per minute.

Next, calculate your zone.

"Take the number 220, then minus your age, then calculate 70% of that number for your target beats per minute," says Austin, and that's your zone. "If your heart rate halfway through your workout is over that 70% mark take it down a level, and if under, pick up the pace."

Not a math wiz? There are easier ways to figure it out.

"Another great way to find out your zone is to get a pulse monitor, which takes the math out of it," says Austin. "Or very simply, take the talk test: while you are doing aerobics, talk a sentence. If you are too winded to finish the sentence, you are overdoing it, or if it's too easy to say, kick it up a notch!"

Getting Cut With Cardio

If you're looking for ripped abs and toned arms, interval training will help get you there -- especially if you throw in some weights.

"I love interval training because it consistently jump-starts your metabolism," says Austin. "Let's say you are walking -- you could power-walk really fast for three minutes to get the burst of calorie burn, and then walk calmly and slowly for one minute, which offers recovery. By switching back and forth, you push the muscle and let it relax over and over and this gives you maximum results." You can do interval training on any type of cardio exercise machine -- alternating a high intensity with a more moderate level.

Austin suggests doing weights during your recovery time, such as bicep curls or tricep toners, to reap the benefits of both cardio exercise and weight training, and along with interval training, add dedicated weight sessions to your regimen to burn fat and sculpt muscle at the same time.

"Do cardio four days a week for 30 minutes, and add a weight-training workout at least two times a week at 20-minute sessions," says Austin. "Cardio will burn the fat, and it's the weight training that gives you the toned sculpted look that will have you bikini ready."

Cardio's Best Fat Burner

So you want the bottom line: Which cardio exercise will fat-bust the best?

"Running is the best option for calorie burning, in my opinion," says Niki Kimbrough, personal fitness expert with Bally Total Fitness. "Whether it's outside or on a treadmill, it's the best exercise because you're burning calories and you're strengthening your legs and heart -- it'll get you nice and lean."

Beginners should start with 20 minutes, explains Kimbrough, and work their way up.

"It takes about 20 minutes for your body to get going, and then your body starts to kick it to another level," says Kimbrough. "Ideally, you want to run for about 30 or 45 minutes."

For those with bad knees, Kimbrough recommends the elliptical machine as a good second choice.

In case running isn't your game, Kravitz takes another track.

"I really feel the most important message is to chose a cardio modality or modalities that you like," says Kravitz. "Because in the final outcome, if a person enjoys a mode of exercise, that is what all research shows they will choose."

Splitting It Up

While it may not be the fastest way to a body built for the beach, splitting up your cardio exercise still has its benefits.

"In order to achieve the best results, and also in order to maintain a healthy heart, it is best to not split up your cardio workouts," says Austin. "You need the consistency of 20 minutes or more of an elevated pulse to ensure great results. However, something is better than nothing. If all the time you have is 10 minutes or even five minutes, it is better than sitting still; you will still be garnished benefits and lose weight."

Kick Up Your Cardio

Let's be honest -- cardio exercise can get boring after awhile. How can you jazz it up and make it interesting again? The experts recommend never letting it get stale in the first place.

"I believe you should do different types of cardio exercises during the course of a week, if possible," says Austin. "The thing to remember is that too much repetition will fatigue muscles and you will plateau, which will slow your results down. By adding variety to your workouts you give muscle groups a chance to recover on their days off and you can maintain a steady progress."

Kravitz agrees with adding options to cardio exercise.

"Vary the mode, vary the place you train, vary the workout, vary the time of day, vary the intensity of the workout, vary the duration -- vary, vary, vary," says Kravitz. "That is what I have found to work the best for exercise compliance."

Before starting a new exercise program, it is important to have a discussion with your doctor about types and levels of activity. Your doctor can advise on any limitations or restrictions you may have.