7 Exercise myths debunked

By Naveed Saleh, MD, MS
Published March 1, 2021

Key Takeaways

The most recent government statistics on physical activity are sobering. According to Healthy People 2020, an initiative of the Department of Health and Human Services, only 24% of American adults aged 18 years and older met current federal guidelines for aerobic physical activity and muscle strengthening.

Intriguingly, in Americans aged 25 years and older, exercise rates were highest among those who had advanced degrees, with 35% meeting the guidelines, compared with 30.1% who had a 4-year degree, and 14.6% who completed high school.

But regardless of education or exercise intent, anyone can fall for exercise myths. Here’s a closer look at some of the common misconceptions.

Myth #1: Exercise always results in weight loss

It’s true that if you exercise a lot, you will probably lose weight or at least prevent weight gain. According to an article published in the International Journal of Obesity, exercising more than 250 minutes weekly resulted in clinically significant weight loss of more than 5%. Weight loss, however, can vary and is idiosyncratic.

“There are large inter-individual differences in weight loss despite participants engaging in similar amounts of exercise,” the authors wrote. It’s been postulated that these differences are related to biological changes (ie, reductions in resting metabolic rate and total daily energy expenditure) and behavioral changes in non-exercise physical activity or energy intake compensation, “resulting in less weight loss than theoretically predicted by the amount of energy expended from exercise.”

One factor that might mitigate weight loss in those who exercise is the replacement of fat-tissue weight with muscle-tissue weight. It’s important to have more muscle weight than fat weight. Remember that muscle weighs more than fat—however, it burns more calories than inactive fat, even at rest.

Myth #2: You can lose weight from ‘spots’

“Spot reduction” is the targeted loss of fat through specific exercises, and it’s a popular myth because it seems intuitive. For example, it’s tempting to think that abdominal crunches will help you lose belly fat. Not so, according to Mercy Health. Instead, your body loses fat proportionately, based on calories burned. 

We can’t directly burn fat in fat cells because fat takes the form of triglycerides. Muscle cells don’t use triglycerides as fuel. Fat must be metabolized into glycerol and free fatty acids, which enter the bloodstream, so in reality, fat broken down for fuel can come from anywhere in the body. 

Myth #3: Preventive stretching is a bad idea

The data on stretching are mixed. Some experts say stretching before exercise may actually make you weaker and slower. Recent research, however, points to benefits of preventive stretching. 

According to the findings of a randomized-clinical trial involving 124 male high school soccer players, researchers found that personalized stretching programs benefited players.

“Instructed stretching exercises, personally designed by physical therapists to address muscle tightness, improved the range of motion and trunk flexibility, with a positive effect on the injury rate in male high school soccer players, especially for non‐contact disorder injuries during training,” the authors concluded.

Myth #4: Those who exercise need less sleep

Not true! According to the Utah Department of Health, exercisers need more sleep. The agency does point to an important sleep benefit due to exercise. “One of the benefits of regular exercise is that you are going to fall asleep faster and you are going to sleep more deeply, so you are going to have more restful sleep.”

That notion is backed up by research, according to Johns Hopkins Medicine

“We have solid evidence that exercise does, in fact, help you fall asleep more quickly and improves sleep quality,” said Charlene Gamaldo, MD, medical director of Johns Hopkins Center for Sleep at Howard County General Hospital, Columbia, MD. “But there’s still some debate as to what time of day you should exercise. I encourage people to listen to their bodies to see how well they sleep in response to when they work out,” she added.

Myth #5: Eat more protein to gain muscle mass

Research evidence has gone back and forth on the popular notion that adding extra protein to the diet through food sources or supplements builds muscle mass, according to an article published by the Center for Science in the Public Interest.

“Despite an abundance of conflicting evidence, the belief persists that protein supplementation during resistance exercise training will enhance muscle mass and strength,” said Blake Rasmussen, professor and chair of the department of nutrition and metabolism at the University of Texas Medical Branch in Galveston, in the article. However, there is now “an impressive collection of scientific findings indicating otherwise,” he added.

"Despite an abundance of conflicting evidence, the belief persists that protein supplementation during resistance exercise training will enhance muscle mass and strength."

Blake Rasmussen

In one study, Rasmussen’s team randomly assigned 58 healthy young men to ingest either a protein supplement of whey protein isolate (22 grams a day), a soy-dairy protein blend (22 grams a day), or a placebo (maltodextrin) while they took part in a resistance training program. After 12 weeks, the protein groups had gained no more strength than participants who took in no extra protein. Studies on older adults yielded similar results.

Besides its questionable impact on increasing muscle-mass, consuming too much protein can lead to a higher risk of developing kidney stones. And a diet consisting of excess red meat or saturated fat can lead to higher risk of heart disease and colon cancer. But how much protein do you need? Click here to learn more about protein requirements. 

Myth #6: Exercise machines outperform free weights

Exercise machines, including Nautilus, look impressive. Furthermore, their presence in gyms implies a certain cachet that free weights lack. But whether you are using the equipment in a gym or at home, no single type of weight training equipment is right for every individual, notes the Mayo Clinic.

Free weights are relatively inexpensive and versatile, and using them can resemble real-life lifting situations. However, they must be used with proper form and technique to reduce risk of injury. Machine weights are fairly easy to learn how to use and are also effective, as long as the settings are adjusted for your body dimensions. Again, proper technique is important to avoid injury.

Ultimately, the decision is a matter of personal preference and should be based on your fitness level, your goals, and, of course, your access to equipment.  

Myth #7: Peak physical fitness requires a gym or trainer

In these days of the pandemic, going to the gym or working with a personal trainer may or may not be a practical or safe fitness option, depending on your point of view. And besides, if you are motivated, you can reach peak physical fitness on your own. Try checking out the Utah Department of Health’s web-based exercise resources—routines developed by an exercise physiologist that can be done at home, or printed out and taken to the gym. Or try one of the hundreds of online fitness programs that have sprung up during the pandemic.

And don’t feel bad if you’re a person who doesn't relish going to the gym, dreads the idea of doing repetitions on the floor at home, or—dare we say it—just hates exercise, period. There are lots of alternative ways to get moving and even have fun while you’re doing it. Click here to get some ideas.

Bottom line

Regardless of where you’re at with your own exercise routine, it’s never too late to get back on track. And if you’re looking for guidance, the WHO released new evidence-based exercise recommendations last November.

In accordance with these guidelines, adults should perform at least 150-300 of moderate-intensity aerobic activity or 75-150 minutes of vigorous-intensity aerobic activity weekly—or an equivalent combination throughout the week. Two or more times weekly, adults should perform muscle-strengthening exercises at moderate or greater intensity, involving all major muscle groups for additional health benefit.

Share with emailShare to FacebookShare to LinkedInShare to Twitter