Talk to a Zone Specialist: 800-404-8171

Fat-burning and muscle-building myths persist

By Lisa Ziegler

Despite the plethora of information that is now close at hand thanks to digital media and means of delivering it (i.e. smart phones, tablet computers, social media, and more), certain myths centered on concepts about fat burning and muscle building still persist. Perpetuation of these myths could result in the loss of potential gains in fitness and lead to confusion as to what the proper approach should be. So what is the real skinny? Read on for information about two of the most prevalent misconceptions.

  • To burn fat, you must stay in a "fat-burning zone" during cardiovascular exercise

    This one has even been perpetuated by equipment manufacturers, including a "fat-burn" program on treadmills and stationary cycles. The idea is that by maintaining a specific range of heart rate, usually around 50-65 percent of one's maximum heart rate, one will be in an optimal range for burning fat versus "muscle" (meaning fuel stored in muscle, as mentioned below). This is only somewhat true. In fact, the percentage of fat utilized may be somewhat higher at this range of intensity; however, the total number of calories burned will be less than if you engaged in a higher intensity. Even at a shorter period of time this extra effort burns more calories overall, which will still result in fat loss (especially if the proper eating habits are followed). Of course, this range of heart rate is still safe and optimal for beginners.

    Another problem is that there is a large margin for error in using just heart rate to calculate exercise intensity. Factors, such as faulty computation by either the machine (treadmills with built-in heart-rate sensors) or the exerciser (when using a manual method), can throw off the entire process. Or, if a person is taking medication that alters his or her heart rate (for blood pressure, etc.), this further confounds the issue. Using "RPE" or "rate of perceived exertion" (i.e. on a scale of 1-10, with 1 being easiest and 10 being hardest) is an easier, accurate method that anyone can employ.

    In any case, rest assured that no matter what intensity level you are engaging in during cardiovascular activity, you are always burning a combination of fat and stored glycogen (carbohydrates converted to muscle fuel), but it is the overall number of calories you expend that is more important, especially if losing weight is your goal. If you are a beginner and are just seeking to gain basic fitness and endurance, staying in the lower to moderate intensity level is best at first; once a baseline level has been established, you can bump it up at your own pace.

  • To lose weight, perform only cardiovascular exercise to avoid "bulking up"

    Many a beginner hits the gym and heads straight for the treadmill, where he or she walks, or runs; then walks or runs some more. Sometimes, for variation the elliptical machine is favored. The resistance-training area of the gym is still a foreign concept, which is a shame since resistance training should go hand-in-hand with "cardio." In the overall scheme of things, cardiovascular activity does burn more calories per session but not as much as most people hope for, (and the calories-burned readout on the treadmill display can be wildly inaccurate). Adding muscle mass, which is more likely to be gained from resistance training vs. running, is a key factor in the body's ability to burn calories and thus fat. After a session of weight training, the body can continue to burn calories (known as "excess post-oxygen consumption" (or "EPOC"). The fear that one may gain large, unsightly musculature when training with weights or resistance is not helped by ads for certain generalized, "pre-prescribed" exercise programs featuring extremely muscular individuals performing heavy lifts. However, when applied correctly, the types of exercises and amount of resistance and repetitions used are not likely to cause a sudden increase in size. Beginners do tend to see faster gains, but these tend to balance out rather than continue indefinitely. Added weight gain from resistance training is possible, which dismays exercisers, but this is because muscle is more dense than fat. What matters most here are body measurements, which should lean down. If not, then other factors must be scrutinized, especially diet. Muscle also helps increase insulin sensitivity, which means calories taken in are less likely to be stored as fat, and blood sugar levels will be more stable.

    Weight training can be implemented in a progressive structure, ensuring that when a trainee's strength increases, new elements can be introduced to keep the momentum going, such as amount of resistance, repetitions, sets, exercises, tempo, etc. While cardiovascular mode and intensity can also be manipulated, this can only go so far before the body's response plateaus. Weight training can continue to offer gains in lean body mass, and another important aspect to remember is that only resistance training has a building effect on bone density (due to the pull of muscles against bones when performing movements in specific body parts).

    It seems hard enough for people to find the time to get the recommended amount of cardiovascular exercise: 150 minutes of moderate-intensity minimum per week for health and general fitness; or 75 minutes of vigorous activity can be substituted when conditioning allows it. (Don't try it if you're a beginner. Work your way up.) And combining moderate intensity with vigorous is a healthy way to avoid burn-out or injury. After much study and research proving this is a necessary component, the Centers for Disease Control (CDC) also recommends including at least two non-consecutive days of muscle strengthening activity, focusing on at least 8-10 muscle groups. The cardiovascular activity can be broken down into intervals spread out through a day and even combined with muscle strengthening in activities, such as circuit training, so everyone can fit both into a busy schedule.

    To lose fat and maintain a leaner body following evidence-based guidelines are proven to have a positive effect. Explore trusted resources, such as the CDC website or the American College of Sports Medicine ( Avoid getting stuck in a no-results regimen.