This is a claim you hear often, especially among bodybuilders, but also among some personal trainers. The most extreme version is “aerobics makes you fat”, the reasoning being that it leads to loss of muscle, which lowers your metabolism, causing you to gain fat because you’re now eating too much for your slow metabolism.

These types of claims are based on some truth, as we’ll see, but are highly exaggerated. Your muscles are not going to waste away to nothing because you run half an hour per day.

There are some mechanisms by which aerobic exercise can interfere with muscle growth or cause actual muscle loss. The first is that concurrent aerobic exercise and strength training lead to competing adaptations in muscles. For example, steady state aerobics leads to endurance adaptations such as increased mitochondria (aerobic energy factories) and aerobic enzymes in the muscle cells, while strength training can lead to hypertrophy, or growth in muscle fibers.
The bottom line is that doing both of these activities has been shown to cut muscle growth about in half compared to just doing strength training [Docherty, 2001; Gordon, 1967]. For those of us that are doing strength training for fitness this is not a big deal, it just means it will take longer to build up muscle mass. But for bodybuilders it’s interfering with proficiency in their specialty. So many bodybuilders will minimize aerobics or take measures to reduce the intereference.

I think this is where the seed of this “muscle wasting” idea was first planted. But note that aerobics in these studies has been shown to reduce the rate of muscle growth, which is a far cry from causing muscle loss. Interestingly, the opposite interference does not seem to occur: adding strength training does not interfere with cardio improvements. Many of us that are into aerobic training will supplement it with upper body strength work, and there’s no problem with concurrent training in that case.

There is another way that cardio can interfere with strength training, and that can be by just taking up too much time. I remember a time when I was trying to lose weight so I did about 90 minutes a day of cardio. I tried to do a token amount of resistance training but had little time and was worn out anyway. I had much more success when I cut back to a more reasonable hour per day and left more time to lift.

There are a couple of mechanisms by which excessive aerobics can lead to actual muscle loss, however, due to overtraining and/or poor nutrition. Too much aerobics can lead to increased production of catabolic hormones like cortisol (often referred to as a “stress hormone”), which can subsequently cause breakdown of muscle tissue.

But aerobics in moderate amounts is a relaxing activity, which leads to a net decrease in cortisol. Only excessive amounts of aerobic activity leads to elevated cortisol levels in the bloodstream after the activity is complete.

A study which specifically examined how much aerobic exercise is needed found that cortisol elevations did not occur when running for 40 or 80 minutes, but only occurred in runs of two hours [Tremblay, 2005]. Ironically, high volume resistance training can cause the same effect [Stone, 1998], but I’ve never heard anyone being warned not to lift because it causes your muscles to waste away!

The other mechanism is that if your body does not have enough blood glucose, it can manufacture it by breaking down protein. If not enough protein is available from food, it will get it from muscle tissue [Berning, 1998]. Again this is only likely if you’re training excessively, or undernourished.

The most obvious example of this is “hitting the wall” in the marathon or cyclists “bonking” on long rides. You can get irritable and have impaired judgement as the brain, which can only run on glucose, is not getting enough fuel.

I’ve experienced both of these and they’re no fun. I don’t know if my body broke down muscle for fuel but afterwards it sure felt like my muscles had been broken down, or at least beat up. But both times this occurred to me after about 3 hours of exercise without taking in any fuel.

On the other hand, many people that are into aerobics, thinking of carbs as fuel, will bump up their consumption of bad carbs like white flour products or sugary drinks or “power bars” which are basically glorified candy bars. This can lead to an unhealthy lifestyle of poor nutrition justified by overtraining.

There is a way people who do a lot of cardio can end up protein deficient: endurance exercise increases the demand for protein. You’ve probably heard that cardio is fueled by a mixture of carbs and fat, depending on the intensity level, but there’s a small bit of protein in the mix, too. Protein is also needed to repair any tissue damage caused by the exercise [Noakes, 2004].

Strength trainers are well aware that they need more protein, but people who do cardio often are not. In addition, since many who do cardio are trying to lose weight, they’re probably cutting back on calories at the same time, which if you do it by just reducing portion size can decrease protein intake. The typical recommendation for protein is 0.25-0.45 grams per pound of body weight, but endurance athletes can require more like 0.55 to 0.65 grams per pound [Sharkey, 2001].

So don’t overtrain and don’t underreat, and don’t eat junk. Follow common sense procedures like easy day/hard day, don’t do hours per day of cardio, and don’t try to lose more than about a pound of weight per week. Make sure you’re doing a balance of cardio and resistance training, and your muscles will be just fine.

References

-Berning, J, “Energy Intake, Diet, and Muscle Wasting”, in in Overtraining in Sport, Kreider, R, Fry, A, and O’Toole, M, eds, Human Kinetics, 1998.

-Noakes, T, Lore of Running, Human Kinetics, 2002.

-Sharkey, B, Fitness and Health, Human Kinetics, 2001.

-Stone, M, and Fry, A, “Increased Training Volume in Strength/Power Athletes”, in Overtraining in Sport, Kreider, R, Fry, A, and O’Toole, M, eds, Human Kinetics, 1998.

-Tremblay, M, Copeland J, and Van Helder, W, “Influence Of Exercise Duration On Post-exercise Steroid Hormone Responses In Trained Males”, Eur J Appl Physiol, 94(5-6):505-13, 2005.

te fitness magazine, Men’s Health, recently featured an excellent article about David Beckham’s cardio workouts.

Of course, I wasn’t surprised that all of his cardio workouts incorporate some form of interval training because of the simple fact that interval training is scientifically proven to provide greater improvements in fitness and greater fat loss than the outdated and primitive aerobic training alternative.

But, while I was reading over the workout, I was struck with what I’d describe as THE MISSING LINK to most cardio routines for athletes AND for fat loss.

Typical cardio programs have you run in a straight line forever at a SLOW SPEED. Pretty easy…

And while the original Men’s Health program was much better because it uses intervals, it still recommends running in a straight line. Again, not that difficult…

It is critical to understand that your body operates in three fundamental planes of movement:

1.) Saggital Plane: Forward and Backward Movements

2.) Frontal Plane: Lateral Movements (Side-to-Side)

3.) Transverse Plane: Rotational Movements

So, Beckham’s current cardio program is only emphasizing the already overtrained saggital plane (forward running) without any attention to the very undertrained lateral and rotational movements that are critical to a soccer player’s success (and any field or court athlete’s success for that matter).

But the modified cardio program I created for YOU below uses intervals and shuttle runs in 10 yard increments that require constant stop-and-go and change of direction (you can modify the distance as desired) in all three planes of movement. Now this cranks the intensity up to a whole new level!

Your body’s ability to change direction, or decelerate, requires a great deal of body control and energy expenditure when compared to straight line running. Thus stop-and-go shuttles not only are much more sport-specific (read David Beckham is an international soccer star not a marathon runner) but it also leads to greater calorie burning and thus greater fat loss!

So, check out the NEW and IMPROVED David Beckham Cardio Workout for Rapid Fat Loss:

I. Warm-Up- 5 Minutes

II. Intervals- 20 Minutes

Rapid Fat Loss Interval: 60 s on, 60 s off

- Set-up 2 cones 10 yards apart to build the “shuttle”

- Perform one or any combination of the following cardio exercises as listed within the confines of the 10 yard shuttle:

Cardio Exercise#1- Sprint-Sprint Shuttle @ 60 s on, 60 s off

Cardio Exercise#2- Sprint-Backpedal Shuttle @ 60 s on, 60 s off

Cardio Exercise#3- Shuffle-Shuffle Shuttle @ 60 s on, 60 s off

Cardio Exercise#4- Shuffle-Crossover Run Shuttle @ 60 s on, 60 s off

III. Cool-Down- 5 Minutes

Remember, if you want to look like an athlete then you need to train like one. If you are sick of the same old boring “straight-ahead” cardio, then the time is now to break out of your comfort zone so you can harness the fat-burning power of stop and go, multi-directional, and multi-planar interval cardio.

Crank it!

Have you ever tried doing cardio (aerobic) training to lose fat? Did you try the popular method of spending long durations (like 45 minutes to an hour) at a gentle pace so you could be in the so-called “Fat-Burning Zone?”

Me too.

And did you get the body you were after?

Me neither!

I believe this is because there’s no such thing as “The Fat-Burning Zone.” In fact, I think the whole idea is a myth. Just look around the gym at all those fat people you see plodding slowly away on their treadmills and cycling machines, month in and month out, with no results, and you’ll be forced to agree with me. I think the idea of a special “zone” sells well because it sounds scientific, especially when explained by “experts.” It also seems nice and easy – people don’t like to hear that they need to work intensely and sweat hard. But the truth is that gentle and moderate exercise is just going to give you, well, gentle and moderate results.

Because of this failure, all cardio training has unfortunately been given quite a bad name recently, with many trainers and authors rushing out to condemn it as useless. They’re often not being totally honest with you though, and have usually got something to sell you – like “Underground Four-Second Fat Blasting Functional Secrets From Russia!” or something to that effect.

Proper cardio training has always been excellent for fat loss. Here’s the thing though: Proper cardio means intense cardio. To make it work, you have to be seriously sweating. If you exercise so gently that you can read a book or watch TV or even talk on a mobile phone, then naturally you’re going to get no results. Proper cardio training also means doing it for a long enough duration. No, you don’t need to spend an hour or more doing your cardio – but you do need to spend at least 20 minutes if you want to see results.

All this, by the way, is also why I have little time or patience for people who say that all you have to do is take the stairs instead of the elevator at work, or that you can get “all the exercise you need” by doing housework and gardening. That may be good enough for the average person, but why settle for average?

If your aspirations are higher than merely “having a healthy heart” or “avoiding diabetes,” it follows that the quality – and quantity – of your workouts must be that much higher too.

Our health is the most valuable intangible asset we possess. Staying healthy throughout life is key to a more fulfilling, productive and happy existence.

Heart disease tops most lists as the number one health problem in the world. Thus, maintaining your heart health is crucial for your longevity and success and for the health of our society as a whole.

One way of keeping your heart healthy is providing it with enough aerobic training, or with so called cardio workouts, to keep it fit and in good shape. Cardio fitness trains your heart by giving it an extra load of work in supplying your body with oxygen.

Cardio fitness may include any type of physical exercises which trains your cardiovascular system, such as walking, jogging or swimming. When you work out your heart begins to beat faster, your pulse quickens and you start breathing deeper. Repeated exercise gives the heart extra training to stay healthy.

There are three key things responsible for the success and effectiveness of any cardio fitness routine. Those are: duration, intensity and frequency. So, before beginning a cardio exercise routine you should determine your workout goals and schedule. Remember, you should consult with your physician or medical advisor before beginning any training program or fitness regiment.

Let us start with the duration. Usually, one cardio fitness session may last 20 to 40 minutes. The duration greatly depends on your physical condition, your training goals and on the type and intensity of exercises you are doing.

If you are a beginner and only start with a light cardio session then your workouts may last no longer than 10 minutes. Determining the time of these sessions you should take into the consideration your present physical shape.

Avoid overloading your body and overstraining your heart during your exercise routines. Overstraining your heart will do you no good and may cause significant harm to your health and permanent damage to your heart and body. You may experience some discomfort in your muscles and joints as a normal process while your body acclimates to the new cardio fitness activities. However, if you feel any pain then postpone your next exercise session until after you have healed or consulted your doctor to ensure you have not pulled a ligament, tendon, or muscle.

Next, How Intense Are you?. For determining the intensity of your cardio fitness you should know your Maximum Heart Rate (Max HR). You determine it by subtracting your age from 220. For the beginners the HR during the exercises should not exceed 55% of the Max HR.

However, if you are in a good shape and have some experience in working out the intensity of your cardio fitness may come up to 65-85 percents of your Max HR.

Finally, What’s the frequency?. For attaining the best training results to improve your heart health, you should do cardio workouts on a regular basis. Three or four sessions a week is the optimal training frequency. You may also do your cardio daily while changing the type of activity you choose for your workouts. Remember that you must keep at it. No excericise program will be easy to keep up with, and you must make an concentrated effort to stick with the program.

Keeping in mind the three keys of cardio training you will help you heart stay healthy and attain excellent results through your workouts. Your can improve both the quality and prolong your life by keeping your heart healthy with regular exercise.