Exercise, Fitness

December 26, 2008

Debunking Fitness Myths Part II

In my last blog I covered a few of the more common fitness myths that pervade society. In the true spirit of the adage, “Believe none of what you hear and only half of what you see!” here are three more exercise myths that come up again and again.

MYTH 1: You should perform cardio in your “fat burning zone.”

TRUTH: Step into any gym and you’ll hear personal trainers preaching that the best way to lose weight is by exercising in your “fat burning zone.” While this might sound good in theory, the “fat burning zone” is actually based on faulty interpretation of research showing activities performed at a low intensity (60 to 80 percent of max heart rate) burn a greater percentage of fat calories than higher intensity activities.

Fact is burning a greater percentage of fat doesn’t equate to burning more total fat calories. High-intensity exercise burns more fat calories on an absolute basis than lower intensity activities, making it the preferred choice for those looking to optimize fat loss.

One of the best fat-burning forms of cardio is interval training, where you intersperse periods of high-intensity exercise with periods of low-intensity exercise. This not only maximizes fat burning during the activity, but also increases a phenomenon called excess post-exercise oxygen consumption (EPOC) — the amount of calories burned once the activity is finished — which helps keep your metabolism elevated long after you’ve stopped working out.

MYTH 2: Sweat is a good indicator of exercise intensity.

TRUTH: You’ve no doubt heard fitness pros utter the phrase, “Ya gotta sweat.” Many people adopt this as an exercise mantra, believing it’s the key to a successful workout. Not!

While sweat tends to be associated with rigorous exercise, it is by no means essential to achieving results. If it was, you’d get buff lounging in a sauna!

Fact is sweat is an indicator that your body temperature is rising, not necessarily that you are exercising at an intense level. Your body regulates its temperature by activating your sweat glands, which then pores as a cooling mechanism.

Rather than focusing on how much you sweat, the best way to monitor exercise intensity is by using a rating of perceived exertion (RPE). This is a subjective scale that estimates how difficult an activity is to perform. I like to keep it simple and use a scale of 1 to 10, with 1 being complete inactivity and 10 being all-out effort. If you want to exercise intensely, maintain a level of an 8 or more on the RPE scale.

MYTH 3: If you stop lifting weights, your muscle will turn to fat.

TRUTH: Some people refuse to lift weights for fear that their hard-earned muscle will simply morph into fat if they stop working out. Nonsense! Muscle and fat are two separate and distinct properties that have completely different molecular structures.

Muscle is a protein-based tissue comprised of filaments called actin and myosin. Body fat, on the other hand, consists of stored triglycerides, which are made up of a carbohydrate (glycerol) and three fatty acids. Hence, the possibility of muscle turning into fat (or vice versa) is akin to an apple becoming an orange: There’s simply no mechanism for it to happen.

Bottom line: don’t let the “muscle-to-fat myth” deter you from lifting weights. The only thing that happens when you stop weight training is that you ultimately lose the muscle that you’d developed.

On the plus side, muscle has “memory” so it’s easier to get back that muscle when you re-start your routine!