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The 21 Biggest Exercise Myths, Debunked by Science and Health Experts

The truth behind some of the biggest myths about exercise that you've believed for years!

Between Instagram influencers, fitness bloggers, and self-proclaimed "gurus," there's a veritable treasure trove of information out there about exercise. But unfortunately, not all of it is accurate. Did you know, for example, that all of that stretching you're doing to prevent injuries is for naught? Or that you should be ending your workout with cardio, not starting with it? And you probably believed that muscle weighs more than fat, right? Yes, the chances are high that you're going about exercise all wrong—and these examples are just the tip of the iceberg! Read on to find out whether or not the so-called "truths" you've longed believed about exercise are actually backed by scientific studies and doctors. After that, you can start working out smarter—and more effectively—today!

Myth: Stretching prevents injuries.

stretching exercise myths

Fact: The thinking goes that loosening your muscles up pre-workout will make you nice and limber, thus minimizing the chance of any muscle tears or pulls, but a 2007 study published in the journal Research in Sports Medicine debunked that notion. The researchers from the University of Hull in England "concluded that static stretching was ineffective in reducing the incidence of exercise-related injury."

Instead, to truly stay safe, you'll want to do a warm-up exercise to increase blood flow to your muscles, which prepares them for the impending workout. In a 2018 study published in the Journal of Exercise Rehabilitation, researchers noted that warm-ups "are performed for 5 to 15 minutes before engaging in the main exercise" in order to "lower the risk of injuries in the muscles and tendons."

Myth: Fat can turn into muscle and muscle can turn into fat.

Couple Lifting Weights, look better after 40

Fact: You can burn fat and build muscle (sometimes even with the same routine!), just like you can gain fat and lose muscle. But make no mistake, fat and muscle are two different types of tissue, and you can't turn one into the other. "The best analogy I can use is, you cannot turn an orange into an apple," Brad Schoenfeld, an assistant professor of exercise science at the City University of New York's Lehman College, told LiveScience.

Myth: You start losing muscle mass after just a week of inactivity.

woman bullied at gym

Fact: It may be true that, if you've just taken up a routine, taking time off can quickly eradicate your gains. But if you exercise regularly—several times per week for several months—it'll take longer than seven days for your strength to evaporate. According to a 2007 study published in Archives of Physical Medicine and Rehabilitation, for athletes, "strength performance in general is maintained for up to four weeks of inactivity."

Myth: Doing more cardio means you'll lose more weight.

Running with Friends {Healthy Habits}

Fact: Despite what you may think, spending hours on the treadmill isn't the quickest way to shed those extra pounds. According to the Mayo Clinic, about 3,500 calories equals one pound of fat. So, to burn that pound of fat, you'll need to burn 3,500 calories. And, according to a 2018 article in Runner's World, the average person burns about 100 calories per mile of running. In other words, to burn one pound of fat, you'd have to run 35 miles, which is only a few miles shy of a marathon and a half!

Myth: Early morning is the best time to work out.

morning run exercise myths

Fact: Working out first thing in the morning is a great method for kickstarting your metabolism—and as a bonus, you needn't worry about slating in an inconvenient workout later in the day. As such, many people swear by the practice. But, according to a 2019 study published in the Journal of Physiology, working out between 1 p.m. and 4 p.m. is just as effective as working out early in the morning. It all depends on if you're naturally a morning person or not.

Myth: The number of calories your cardio machine says you burned is accurate.

an old man doing warm up exercising on the treadmill, home hazards

Fact: There's nothing like finishing a long workout on the elliptical and seeing how many calories you've burned. It gives you a tangible indication of accomplishment, right? But it turns out, it's best you take the number you see on the machine's digital display with a grain of salt. According to a 2018 study published in the journal Exercise Medicine, you should expect the elliptical to overestimate your results by about 100 calories per 30 minutes of exercise. A similar padding of the numbers likely occurs with treadmills, as well.

Myth: Doing crunches and sit-ups will get you six-pack abs.

senior woman on yoga mat, crosses arms in preparation for crunches

Fact: Crunches, sit-ups, and other ab exercises are great for building core muscles and, if done frequently and properly enough, they can help tone your abs into a sheet of muscle—but only if you have a good diet in place. The saying, "Abs aren't made in the gym. They're made in the kitchen," is at leas partially true. "There seems to be a lot of misconception about looking cut, ripped, shredded, or whatever you wanna call it," writes strength and flexibility expert Antranik Kazirian on his website. "If you have a thick layer of fat surrounding your abdomen, you're not going to see the tendinous intersections that create the six- (or eight-) pack.  It doesn't matter if you have the ability to literally do 100 sit ups in a row or if you could deadlift 400 pounds."

Myth: Workouts should be at least an hour.

People taking a step workout class

Fact: According to a 2012 study in the Journal of Physiology, folks who exercised for only 30 minutes can show the same gains as folks who exercise for an hour—or better! On average, the study subjects who exercised for 30 minutes a day lost eight pounds in three months, while those who exercised for a whole hour only lost six pounds. "We can see that exercising for a whole hour instead of a half does not provide any additional loss in either body weight or fat," researcher Mads Rosenkilde, a PhD student at the University of Copenhagen, said in a statement.

Myth: You should hit the gym every day.

people exercising at the gym

Fact: Simple logic dictates that more exercise means better health, and that, if you can swing a daily visit to the gym, you should. But your body needs to rest and allow muscles to cool down. Skipping rest means that, once you get back to the grind, your muscle fibers will be too worn out to grow.

"Over the 24 to 48 hours following your workout, your body struggles to rebuild those muscles, resulting in their improved strength, endurance, and tone," writes Nicole Meredith of the Toronto YMCA. "You've probably felt this happening, in the form of soreness and tightness the day after a good workout. But if you hit the gym for a second time the next day, you interrupt the process, rerouting the energy your body is trying to use to re-build your muscles to yet another workout." For the best results, take a day or two off each week.

Myth: You should do your cardio first.

going to the gym, downsizing your home

Fact: It's nice to get your cardio out of the way at the start of your workout, but it doesn't mean it's an effective strategy, according to Max Lowery, a personal trainer and founder of the 2 Meal Day intermittent fasting plan. "It's a huge mistake doing your cardio and exhausting yourself before you do weights," Lowery told Business Insider in 2017. "Cardio will deplete your muscle glycogen stores, which is essentially your stored energy for explosive activity. This means your strength and weight training will be much less effective."

Myth: Lifting weights will bulk you up.

Woman lifting dumbbell Exercises for Adding Muscle

Fact: Sure, when you begin a lifting routine, you'll start to add some muscle to your frame. But it takes a lot of work—from counting calories to methodically increasing how much weight you are lifting—to truly get bigger, says Jacqueline Crockford, CSCS, of the American Council on Exercise. "Gaining muscle mass comes from a combination of heavy weight training and an excess in calories," Crockford told Shape. "If you perform resistance training one to three days per week and you're not eating more calories than you expend in a day, you probably won't see a ton of muscle growth."

Myth: And "lean muscle" is different from "bulk."

skullcrusher Exercises for Adding Muscle

Fact: You may have heard people throw around the term "lean muscle." (As in, "I don't want to get bulky. I just want to build lean muscle.") But despite the term's place in the fitness lexicon and its prevalent usage among gym goers, "lean muscle" isn't really a thing.

As Pamela Geisel, MS, CSCS, CPT, an exercise physiologist at the Hospital for Special Surgery's Tisch Sports Performance Center, told Self in 2017, "'Long, lean muscles' became a popular marketing scheme targeted toward women who were afraid of 'bulking up.'" But, she noted, muscles are lean by nature, so you can't really make them more or less so. "No form of training alters the visual length of your muscles," Geisel added.

Myth: Lifting doesn't help with weight loss.

Man lifting weights and working out at the gym

Fact: When it comes to losing weight, many people head straight to the treadmill. But if your goal is to burn some serious calories, don't avoid the weight room. According to 2019 research from Harvard Health Publishing, a person who weighs 155 pounds burns, on average, 112 calories from 30 minutes of weight training, or 224 calories in an hour. And while it's not as much as running—which by comparison, burns 298 calories in 30 minutes for a 155-pound person—it's certainly nothing to scoff at!

Myth: To get large, you must lift large.

bench press exercise myths

Fact: A 2016 study published in the Journal of Applied Physiology conducted at McMaster University seems to disprove this pervasive exercise myth. Researchers tested two groups of lifters: One group lifted heavy weights for 8 to 12 reps, while another lifted light weights for 20 to 25 reps. At the end of the 12-week study, participants from both groups gained the same amount of muscle on average—about 2.4 pounds worth—proving that the number of reps and the amount of weight lifted are what collectively builds muscle.

Myth: Bigger muscles translate to greater strength.

bicep curl exercise myths

Fact: Even if someone looks like The Hulk, they're not necessarily stronger than someone with a more wiry frame. Per 2015 research published in the journal Experimental Physiology, weight lifters and sprinters actually have stronger muscle fibers—at least on a cellular level—than bodybuilders. However, the action hero-sized individuals turned out to have more muscle fibers. It's a classic quality versus quantity scenario.

Myth: Spot-training can help you lose fat in a specific area of your body.

spot training woman waist exercise myths

Fact: Spot-training is the idea that you can burn fat cells from a specific area on your body by working it out heavily. It's the notion that, if you do hundreds of leg lifts, you'd incinerate fat off your lower abdomen. Or, if you do thousands of squats, you'd do the same to your quads. But before you let anyone talk you into spot-training, know that science indicates it does not work. A landmark 1983 study from the University of Massachusetts published in Research Quarterly for Exercise and Sport had participants do 5,000 sit-ups over the course of 27 days. But there were no significant change in the subjects' body weight or body fat by the end of the study.

Myth: The more you sweat, the more fat you will burn.

sweaty woman in humid climate

Fact: During an intense cardio session, you may feel like the pounds are literally sweating off of you. But sadly, that's not the case. According to 2008 research in ACSM's Health & Fitness Journal, you indeed lose weight when you sweat, but you are losing water, not fat. Sweating is your body's way of cooling down by releasing stored hydration. All it means is, you need to rehydrate.

Myth: Sports drinks are good for you.

gatorade exercise myths

Fact: When you do rehydrate after sweating it out, make sure it's not with a sports drink, which is loaded with sugar. For instance, your standard 20-ounce Gatorade contains 34 grams of the stuff. So by drinking one, you're just inhibiting your progress. According to a 2019 article on, the popular sports drink is effective when it comes to delivering certain electrolytes, but if your body doesn't need them, stay away from it because you are adding unnecessary sugar, calories, and sodium to your diet.

Myth: For maximum results, you have to gain protein immediately.

protein powder exercise myths

Fact: In your gym's lobby, you may see those with the biggest muscles guzzling protein shakes. These folks are trying to capitalize on the idea of an "anabolic window," or the timeframe post-workout where your body's protein synthesis—or muscle-building period—is at its max. Common thinking decrees that this period is roughly 30 minutes. But, according to a 2018 article in U.S. News & World Report, the anabolic window may extend as long as 24 hours after your workout. It's not that there's any harm in immediate protein consumption; it's just not as necessary as previously thought. For example, in a 2017 study published in Medicine & Science in Sport & Exercise, when men drank 22 grams of protein after their workouts, they didn't build more muscle than those who didn't.

Myth: Working out with a friend is distracting.

Two Men in Gym Locker Room Awkward Moments

Fact: If you hit the gym with a pal, you may be drawn into conversation, but tag-teaming your efforts can also supercharge your routine. According to a 2015 study in the Journal of Personality & Social Psychology, exercisers work harder when they're doing it side-by-side with a friend. Plus, working out with someone makes you more accountable!

Myth: If you gain weight, that means you're getting fat.

scale exercise myths

Fact: When you first start exercising, your weight might stay exactly the same. And even more startlingly, it could also increase. While seeing this happen in real time could be dismaying, it's no cause for alarm. More likely than not, it's just your body adding muscle tissue, which means additional weight. If the weight you gain in muscle doesn't cancel out the amount of weight you lose in fat, you are technically gaining weight, but still losing fat. "You can lose 10 pounds of fat and gain 10 pounds of muscle and the scale shows no change," explains Roberta Anding, a registered dietitian and assistant professor in the Joseph Barnhart Department of Orthopedic Surgery at Baylor University. "If your goal is to lose body fat and get stronger, a traditional scale may not be your friend. Advanced body composition tools that determine the percentages of fat, muscle, bone, and water in your body can give you a better assessment of body composition changes."

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