September 13, 2010

If You're Going To Do Cardio, Do It Right So You Don't End Up In Worse Shape

A lot of people associate weight loss with ‘cardio’, assuming that if they want to ‘tone up’ that their efforts are best spent slaving away on a piece of cardio equipment at the gym, but this just isn’t an effective way to go about losing weight at all. While there are benefits to doing cardio, if the goal is fat loss and improved body composition, then there are much better ways. Humans are not aerobically designed like we once were thousands of years ago. We’ve adapted to become more anaerobically designed, which means short bursts of energy followed by brief periods of recovery is how we are meant to perform.

If you look at the sports world, Olympic marathon runners and triathletes have body fat percentages ranging from 11 to 14%. Olympic sprinters and 400 to 800 meter runners have bodyfat percentages ranging between 4 and 6%. This should provide a clue in that if we want to look a certain way we ought to perform a certain way. This real world example likely raises the question, ‘how is it that the hypothetical cardio guy is relatively fatter than the explosive guy’? The reason for these very different adaptations is because it’s the intensity of the exercise that matters, not the duration, and full blown sprints are a lot more physically demanding than seemingly dragging your ass, irrespective of the longer distances.

Slow paced cyclic aerobic work like the cardio that most people do to lose weight interferes with the brain’s ability to recruit the high-threshold motor units and thus interferes with strength and power development, which negates the potential positive effects of anabolic hormones levels in response to exercise. I don’t know about you, but I can’t see many people consciously striving to become slower, weaker, and fatter, especially those involved in athletic competitions at any level. If you train slow, you’ll be slow. Unfortunately this is what happens to a lot of athletes whose coaches are uneducated in the field of strength of conditioning, and have their athletes run laps as of form of “training” or punishment. All they’re really doing is taking an athlete and making them less effective, which is especially a huge mistake if the athlete competes in an anaerobic sport that requires explosiveness like American football, basketball, or hockey (to name a few).

Aside from the negative effects cardio has on athletic performance, are the overwhelming catabolic effects that it has on body composition. Yes, cardio CAN make you fatter!

Physical activity, whether that be lifting weights or doing cardio, elevates cortisol levels, which is a stress hormone associated with fat gain around the midsection. The major difference between the two types of physical activity is that with weight training, powerful anabolic hormones are increased as well in response to the training, which completely negates the negative effects of elevated cortisol. With cardio, anabolic hormones are not increased in response to the training, and by default, the ratio of cortisol is relatively higher. So basically cardio increases stress hormones in the body without having a boosting effect on anabolic hormones, thus creating a muscle-wasting situation. If your cortisol levels are chronically elevated, your body will store more fat, as opposed to burning it.

What you may not know is that cortisol increases oxidative substances (free radicals) in the body that produce inflammation all over the place, which basically means, it accelerates aging. Inflammation is generally the common denominator of all major health concerns that affect people these days such as, heart disease, diabetes, asthma, cancer, fat gain, etc. With strength training there is acute inflammation following a workout, only in this case it has a protective effect on the body by localizing blood flow to the damaged tissue.

Inflammation becomes chronic however, when the cells are repeatedly attacked by free radicals, elevated insulin (from eating excess carbs), or high cortisol (stress). So you’re starting to see how cardio, which you may have thought was a healthy activity, can actually have an opposite effect, as it produces free radicals due to the increased amount of oxygen you’re breathing in, as well as chronically elevating cortisol from repeated physical stress.

The good news for the people who actually like doing cardio is that there are benefits from performing cardio in high intensity intervals. As stated earlier, humans have adapted to become anaerobic beings, and it is the intensity that matters, not the duration. Remember the sprinter-marathon runner comparison? The reason that sprinters have higher levels of muscle mass, and lower levels of bodyfat is because sprinting itself is a lot harder than slow paced running/jogging.

High intensity interval training recruits a lot more of the high-threshold motor units than slow cyclic aerobic work like jogging, and also prevents the nervous system from becoming accustomed to recruiting low-threshold motor units, therefore maintaining ability to generate maximum force.

As far as caloric expenditure is concerned, what many fail to take into consideration is that repairing the muscular damage from the fast eccentric contractions during sprinting is a relatively expensive process, and is what keeps the metabolism elevated for long after your done training. Most people only look at the calories burned during cardio, failing to recognize that the amount of calories burned to recover from exercise adds up and has a more profound effect on metabolism.

The high intensity efforts that make up interval training, combined with repeated bouts with incomplete rest intervals increase lactate accumulation, which triggers your body to produce more GH (growth hormone). The lactic acid accumulation lowers your body’s pH levels, and the body compensates by elevating growth hormone levels, which have very positive effects on body composition (building muscle, burning fat). It is for these reasons that “cardio” is probably one of the least effective and efficient ways to go about losing fat, and why if you’re going to put in the time to actually do something, you may as well put in the effort needed to get a more positive result. Remember, it’s about effort, not putting in time.

If you have any questions in regards about cardio, feel free to contact me at I'm available for online consulting and personalized program design, as well as one on one training if you are located in the Greater Toronto Area (GTA).

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