6 Fitness Myths, Busted (And 3 Surprising Facts)

September 21, 2015 Updated: September 21, 2015

If you want to be optimally healthy, including staying fit, happy, and vital, exercise is essential. Most people are well aware of this, yet many do not exercise and, among those who do, many fall short of reaching their fitness goals.

Part of the problem is the advice itself, as recommending “exercise” is about as useful as recommending a “healthy diet.” Unless there are more specifics… length of time, intensity, activities… many people will fail. 

This is true even if you’ve been following conventional exercise recommendations, many of which are now outdated. And even though there’s a vast amount of information available to teach you how to best exercise, not all of it is accurate.

If you’re ready to start an exercise program, or improve the one you’re already using, keep reading. Following are several of the most common fitness myths – and what to do instead.

6 Fitness Myths to Avoid to Get the Body You Want

Crunches will provide some toning of your abs, but you’ll get “flat” abs only by burning off fat. (Antonio_Diaz/iStock)


Myth #1: Crunches Are the Key to Flat Abs

Crunches will provide some toning of your abs, but you’ll get “flat” abs only by burning off fat. This means fat-burning exercises are going to be essential. In fact, research has shown that doing abdominal exercises alone—even when performed five days a week for six weeks—has no effect at all on subcutaneous fat stores and abdominal circumference.

High-intensity interval training (HIIT) is among the best fat-burning exercise out there, but even core-building planks and bridges will burn fat (and work your abs) far more effectively than crunches. You can find six more tips to burn your belly fat here (and five of them don’t include any exercise at all).

Myth #2: More Sweat Equals a Better Workout

Virtually any type of intense exercise will prompt you to sweat, but the amount of sweat isn’t an indication of how many calories you’ve burned. Remember, sweating is a natural, essential body process designed to help your body stay cool, so exercising in warm weather (or in a heated room, such as in Bikram yoga) will create more sweating.

While you can’t use your amount of sweat as a gauge of exercise intensity, you can assume that if you haven’t broken into a sweat at all your exercise is probably not intense enough. Additionally, sweating in and of itself may be beneficial (independent of its association with exercise), as it can facilitate toxin excretion. And many with untreated hypothyroidism have a hard time sweating at all. 

Myth #3: Running Is Bad for Your Knees

Running will not necessarily “ruin” your knees, as you may have been told. In fact, research shows that osteoarthritis of the knees is no more common in older adults who engage in long-distance running than in those who don’t.

That being said, women are up to six times more likely to suffer from a knee injury due to running, compared to men, because they may have an imbalance in strength between their quadriceps and hamstrings. Regular strength training, including of your legs, is therefore important if you’re a runner.

Personally, I was an avid runner for over 40 years, but I now prefer HIIT for my aerobic exercise, as it is safer, more efficient and more effective. If done appropriately, however, running can be an effective part of your overall fitness plan and may even help you to live longer. But you must keep it moderate, and find your own “Goldilocks Zone.”

Dr. James O’Keefe, a research cardiologist and former elite athlete, recommends running no more than 20 miles per week, spread out over three to four days, at a speed of about five miles per hour. If you run farther or faster than that, you may lose all the benefits, and the associated health risks can rise to the magnitude of the couch potato—literally—according to the science. 

Myth #4: Stretching Is Essential for Recovering Faster

Cooling down at all after a workout is more of a personal choice, rather than a necessity for reducing muscle pain (sumnersgraphicsinc/iStock)

Stretching does little to influence blood lactate levels (a measure of muscle fatigue) after a high-intensity workout, according to recent research. So while post-workout stretching may help you to build flexibility, it’s not necessary for recovery. 

In fact, cooling down at all after a workout is more of a personal choice, rather than a necessity for reducing muscle pain or improving recovery. As far a pre-workout stretching goes, the best type of stretching to do before a workout is dynamic stretching, as opposed to static stretching (which is what most people do).

Myth #5: You’ve Got to Exercise for at Least 45 Minutes

Conventional aerobic exercise performed for long periods at a steady, moderate pace was long considered the “gold standard” of a good workout, but in recent years research has refuted such notions. 

Instead, high-intensity interval training (which requires but a fraction of the time compared to conventional cardio) has been shown to be FAR more efficient and effective, compared to longer, slower cardio workouts. There are many versions of HIIT, but the core premise involves maximum exertion followed by a quick rest period for a set of intervals. 

Myth #6: More Exercise Time Is Better

Most people do need more exercise time, but taking time for recovery is crucial. It is important to realize you can sabotage your fitness efforts by over-exercising. In this case, your body goes into an elevated stress response, keeping your cortisol levels too high. Cortisol, also known as “the stress hormone,” is secreted by your adrenal glands and is involved in a variety of important metabolic functions, such as regulating your insulin and glucose levels, and controlling inflammation. Elevated cortisol will cause your body to store fat instead of building muscle.

Recovery is absolutely crucial to your long-term success. You simply must provide your body with the opportunity to rebuild and restore itself after you stress it with intense workouts. Regardless of what type of exercise you do, always listen to your body, as it will give you important feedback about whether or not you are overexerting yourself.

Three Surprising Fitness Facts

It’s a mistake to avoid strength training, as gaining more muscle through resistance exercises has many benefits (dolgachov/iStock)

CNN recently spoke with top trainers who shared three surprising fitness facts. Remember that knowledge is power, so the more educated you are about fitness, the faster you’ll be able to reach your goals.

1. Lack of Sleep Leads to Weight Gain

When you’re sleep deprived, leptin (the hormone that signals satiety) falls, while ghrelin (which signals hunger) rises. This combination leads to an increase in appetite. Additionally, sleep deprivation tends to lead to food cravings, particularly for sweet and starchy foods. 

Researchers have suggested that these sugar cravings stem from the fact that your brain is fueled by glucose (blood sugar). Therefore, when lack of sleep occurs, and your brain is unable to properly respond to insulin (which drives glucose into brain cells) your brain becomes desperate for carbohydrates to keep going. If you’re chronically sleep deprived, consistently giving in to these sugar cravings will virtually guarantee that you’ll gain weight. 

Getting too little sleep also dramatically decreases the sensitivity of your insulin receptors, which will raise your insulin levels. This too is a surefire way to gain weight, as the insulin will seriously impair your body’s ability to burn and digest fat. Getting proper sleep is therefore crucial for maintaining a healthful weight.

2. Yoga May Not Burn a Lot of Calories

If calorie burning is what you’re after, most yoga classes may not be the best choice. One study by the American Council on Exercise found that a 50-minute power yoga session burns only 237 calories, compared to 500-600 during a 50-minute spinning class. There are, however, still many reasons to give yoga a try, as research shows it has a positive effect on mental health, sleep problems, hormone levels, flexibility, pain relief, core strength, and more.

3. You Won’t Get ‘Bulky’ From Lifting Weights

Many ignore strength training when devising their exercise plan, thinking they don’t want to “bulk up.” However, even with heavy lifting women, in particular, are not likely to become brawny because they have less muscle tissue and produce lower testosterone levels than men. It’s a mistake to avoid strength training, as gaining more muscle through resistance exercises has many benefits, from losing excess fat to maintaining healthy bone mass and preventing age-related muscle loss as you get older. In fact, strength training has a beneficial impact on at least 10 biomarkers of aging (which are the things that tell you how old you would be if you didn’t know how old you were). This includes the following:

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Rounding out your exercise program with a one-set strength training routine will ensure that you’re really optimizing the possible health benefits of a regular exercise program. You can also “up” the intensity by slowing it down. For more information about using super slow weight training as a form of high intensity interval exercise, please see my interview with Dr. Doug McGuff