10 Exercise Myths That Refuse To Die

Finding clear, definitive facts about healthy exercise can be difficult. The exercise industry is a multi-billion dollar business, built partially on selling gadgets and supplements to people desperate to lose weight or look attractive. Meanwhile, good workout plans and simple truths lurk in the background waiting for their time to shine. All of this results in lots of misinformation about exercise. We're taking some of those commonly-held exercise myths to task, and we have science to back us up. Let's get started.

Exercise picture from Shutterstock

We've tackled food myths, more food myths, brain myths, and even body myths. Now it's time to take a look at exercise myths, and we enlisted the help of Dr Brian Parr, Associate Professor in the Department of Exercise and Sports Science at the University of South Carolina Aiken, to help us out. Here's what we learned.

Myth 1: No Pain, No Gain

While it's absolutely true that you should push yourself and try to extend the limits of your endurance when you exercise, it's not true at all that the best workouts are the ones that leave you feeling horrible, sore and beat up the next day. Discomfort is natural, but pain? No way. "The idea that exercise should hurt is simply wrong — muscle pain during or following exercise usually suggests an injury," Dr Parr explains. "However, some muscle soreness is unavoidable, especially if you are new to exercise."

This myth has been debunked by doctors, physical therapists, and researchers of all stripes, but it still persists because most people conflate the idea of pushing themselves to work out harder with pain. This myth is so persistent that even MythBusters tackled it. It's important to remember that your workouts should still be challenging, but if you're experiencing pain, you should stop. In fact, if your workouts hurt, you probably won't be as motivated to continue them, which is exactly what you want to avoid.

Myth 2: Soreness After Exercise Is Caused By Lactic Acid Building Up In Your Muscles

So what is that soreness you get a day or two after working out? It's called DOMS (delayed-onset muscle soreness,) and the belief that it's caused by lactic acid building up in your muscles while you exercise is false. Dr Parr explains that this isn't the case: "A common belief is that lactic acid build-up in the muscle causes muscle soreness. This is based on the fact that during intense exercise like weight training the muscles make energy for contraction anaerobically (without oxygen), which leads to lactic acid production. This is in contrast to aerobic exercises like walking or jogging that produce energy using oxygen, with little lactic acid build-up. This belief that lactic acid causes DOMS has been shown to be false since any lactic acid that is produced during exercise is cleared shortly after you finish, long before muscle soreness begins."

Instead, that soreness is actually caused by tears in your muscle that occur as you exercise — especially if you're just starting an exercise regimen: "It turns out that strenuous exercise leads to microscopic tears in the muscle, which leads to inflammation and soreness. This sounds bad, but the muscle damage is an important step in the muscle getting bigger and stronger. Your muscles are made up of protein filaments that shorten, leading to a contraction," he continues. Essentially, as your body repairs those microscopic tears, you're building new, healthy and strong muscle tissue. This is also the reason why weight training encourages you to increase the resistance or heaviness of your weights as you get accustomed to one level — it's only through this process that you actually get stronger and build more muscle.

If you want to avoid that soreness, Dr Parr suggests you start your exercise program slowly and ramp up over time — don't do too much before you (and your body) are ready, and don't feel bad about taking a day off between workouts to recover if you're too sore. Alternatively, switch up your workouts: skip the weights and go for a run instead, for example. After all, an exercise program that makes you so miserable you'll quit after a week won't do you any good in the long run.

Myth 3: Effective Exercise Takes Long Hours

Speaking of miserable, getting in shape doesn't have to take a really long time. However, the fact that it does for most people is arguably a good thing. Let's be clear: there's no silver bullet, and there's no magic method to get in shape quickly, but there's a great deal of new research that shows a healthy exercise regimen doesn't mean spending hours at the gym every single day. One study, conducted by researchers at McMaster University in Ontario, Canada and published in the Journal of Physiology showed that even 20 minutes per day can be all you need.

Here's the catch: yes, there's an easier way to do this that requires less time, but you'll need to up the intensity of your workouts in order to benefit. The process is called High Intensity Interval Training, a topic we've shown you how to get started with before. Dr Parr agreed that interval training is a great way to cut down on the length of your workouts and get results in less time, but it requires more effort. Essentially, you can get a great workout in 15 minutes a day every day, but most people will make themselves miserable in the process and give up their exercise regimen within a few days. As always, talk to your doctor about what you can handle, start slowly, and find the sweet spot that works for you between intensity and time. If you have an hour to spare every day, use it instead of killing yourself cramming your exercise into a half-hour. If you can handle a super-intense half-hour workout, go for it.

The other point worth making though is that yes, regular, repeated exercise has great health benefits, but if you don't think you can fit in a workout every single day for the rest of your life, that's no reason not to go for a walk today. Even a half-hour walk can make a big difference. Any activity is good activity — don't cheat your body out of it because you don't think you'll be able to do it again tomorrow, or the next day.

Myth 4: You Need a Sports Drink When Exercising To Replenish Your Body's Electrolytes

This is one of those myths that sprung from an original grain of truth. "Sports drinks are important for improving performance in high-intensity exercise that lasts longer than an hour. Think of a marathon or triathlon. The reason: sports drinks provide water to replace what is lost in sweat and sugar (glucose), the fuel muscles need most in intense exercise," Dr Parr explains. What about low-intensity exercise though, or people who just hit the treadmill for a half-hour every night after work, or bike around town on the weekends? Not necessary at all: "For lower intensity or shorter duration exercise sports drinks are not needed. In fact, if you are exercising with the goal of losing weight, the calories in the sports drink you consume might offset the calories you burned during exercise!"

This is a good point, and one often ignored in the ads for sugary, high-calorie vitamin drinks and energy drinks that make you think you need them if you're planning to hit the gym at all. Those drinks are highly beneficial to the people who need them, and they have their place, but for most people doing moderate exercise, water will do. Dr Parr isn't the only person who thinks so, although sports drink manufacturers would disagree (and indeed, the self-styled "Gatorade Sports Science Institute" has an entire page — one that in my research I found copied word-for-word in many other places — dedicated to why sports drinks are great for everyone.)

Myth 5: Stretching Before Exercise Will Prevent Injury

This particular myth is contentious. There are pro and anti-stretching arguments, with staunch support on both sides, but the confusion about stretching comes down to the fact that many confuse "stretching" with "warming up". It's very important to warm up before strenuous exercise, and warming up can prevent injury, but stretching specifically has been shown to at best have little benefit (as this 2007 review of over 10 separate studies (PDF link) published in the Cochrane Database of Systematic Reviews concluded) and at worst inhibist performance (as this 2011 study conducted by the University of Northampton and published in Medicine and Science in Sports and Exercise (PubMed) concluded.)

Even the Centers for Disease Control have said stretching doesn't prevent injuries. We've mentioned this before, and even made the mistake of confusing stretching with warming up before, so it's important that you don't. Make sure you warm up properly before you begin a workout, possibly even include some stretches to limber up and boost your flexibility, but leave the long stretch-sessions to those hours at your desk instead.

Myth 6: Working Out Will Only Build Muscle, Not Help Me Lose Weight

Frankly, most people who start exercising won't see much immediate weight loss, unless everything else in their lifestyle is already optimal. And sadly, because many people don't see that initial benefit, they believe that exercise is worthless and diet is where it's at. That's not the case, according to Dr Parr. "This is a common misconception that just isn't true. It is based partly on research that shows that people who try to lose weight by exercise only lose less weight that people who do diet only or diet + exercise. The reason for this is that is relatively easier to cut back on the calories you eat than it is to burn the same number of calories through exercise."

Dr Parr admits that for many people, you may get a bigger bang for your buck by changing your diet, but the belief that exercise increases muscle mass and therefore will make you gain weight instead of lose it just isn't the case. "Exercise, especially strength training, can increase muscle mass. Some people believe that the added muscle mass leads to weight gain, not weight loss. While exercise could lead to an increase in muscle it is unlikely that someone dieting to lose weight would experience this," he explains. "In fact, when most people lose weight they lose both fat and muscle. If anything, exercise would help maintain muscle and promote fat loss. The decrease in muscle mass during weight loss can lead to a reduction in resting metabolic rate, which is part of the reason that people tend to regain weight following a diet. By reducing the loss of muscle, exercise may help maintain metabolic rate and prevent weight regain."

If you're looking for workout success stories that aren't pulled from late-night infomercials, Dr. Parr suggests you check out the National Weight Control Registry, which is full of personal stories of individuals who lost weight and kept it off, and how they did it. There's no reason to feel alone, or doomed to failure. Remember, your weight isn't the be-all-and-end-all of your health. When combined with diet, exercise can be a powerful combination to help you lose weight, but also live a healthier life. Check out these other great reasons to exercise from the Center for Science in the Public Interest (CSPI), from lowering your risk of diabetes and most forms of cancer to helping with anxiety and depression, all of which are huge health benefits.

Myth 7: Exercise Will Help Me Lose Weight Quickly

The inverse of the previous myth, this is the one that usually turns people off exercise entirely when they spend hours working out and don't see the results they were hoping for. The problem is that exercise can help you lose weight, but it's not the direct "calories in less than calories burned therefore weight lost" oversimplification that's so often repeated. For example, walking a mile in an hour will burn about 100 calories. Sitting in a chair for the same period of time will burn 60 calories. The real weight-loss benefits to exercise come from the eventual ramp-up of tolerance for intensity and duration of exercise that you achieve once you get started.

The Center for Science in the Public Interest (CSPI) busted this particular myth. As you exercise, you'll start walking faster, or maybe running, or perhaps you'll walk longer and spend more time walking. If you walk or run five miles instead of one, you'll burn 500 calories, and while it will take longer, the weight loss benefits scale better over time than sitting at home, so as you train, you'll lose more weight. It's also important to note that — as we mentioned earlier — you shouldn't confuse the weight loss benefits of exercise with the health benefits of exercise, which you feel almost immediately.

Myth 8: You Need to Take Supplements To Build Muscle

This is another myth that's applicable to some people, but not most of us — but you'd never know it from the way supplements are marketed. Supplements can help, especially if you're a bodybuilder or strength trainer, but the typical person who does some weight training two or three times a week to stay fit and build a little muscle mass doesn't need to chug creatine or protein shakes in order to build muscle. Dr Parr explains, "It is true that you need more protein is you want to build muscle size and strength. But you can easily get that protein from food, meaning that supplements are unnecessary. In fact, the protein in most supplements is derived from milk or soy anyway, so you are paying for a supplement manufacturer to extract the protein from food and sell it back to you! Additionally, getting the added protein from food also provides you with energy (calories) and carbohydrates which you need to fuel your workouts."

No one's telling you to skip the protein shake if you think it's tasty and enjoy it, but remember it's essentially another meal, and caloric intake you may not need if you're just going to go home and make dinner. A full meal, if you make something rich in protein as well as other vitamins and nutrients, will give you the benefits of the shake in a more complete package. If you're a serious bodybuilder and you do weight training for hours a day every day, the rules might differ, but for the average person, all the extra supplements you may be adding to your food or drinks aren't likely to do you much good.

Myth 9: If You Don't Exercise When You're Young, It's Dangerous When You Get Older

It's never too late to start a workout regimen and improve your overall health; you just have to be cautious and aware of how to go about it. A 2009 study of over 1800 seniors by the Hebrew University Medical Center and Hebrew University Hadassah Medical School in Jerusalem and published in the Archives of Internal Medicine concluded that seniors who exercised — or even started to exercise — late in life were likely to live longer than those who didn't, and live out their last years healthier than their counterparts who avoided exercise.

CSPI tackled this myth as well, and this article at WebMD is full of myths about exercise and older adults, for anyone who's worried they may be doing their health more harm than good by exercising in middle-to-old age. The key is to find a workout that's at the right impact level for your age and condition — and as we've said before, the health benefits, in areas like memory, anxiety and depression, and even arthritis or joint pain, make themselves apparent almost immediately.

Myth 10: Working Out At The Gym Is Better Than Working Out At Home (or Vice Versa)

Ah, the double-sided myth. No, we're not going to weigh in on whether exercising at a gym is better or worse than working out at home, or vice versa. There are opinions on both sides of the issue, and studies that have come down on both sides as well. The important thing here is to get rid of the "one is better than the other" statement and remember that different people exercise differently. A 2009 article from The New York Times cited a 2008 study published in the Annals of Behavioral Medicine which found people with home gyms are more likely to begin to exercise, but less likely to continue exercising in the long run — but the conclusion wasn't that home gyms are ineffective at keeping people engaged with exercise in the long term, and it wasn't that home gyms are better at inspiring people to exercise. Instead, the study found that what really matters is the individual's personal belief that they have the power to start and stick to an exercise regimen, whether the gear is in their basement or at a gym 10 miles away.

Essentially, those individuals who were able to really motivate themselves to work out and believed they could stick to it were more likely to benefit from a home gym. People who were less confident in their ability to stick to a workout regimen did better with a gym membership, or by making their workouts part of their routine. In the end, both versions of this myth are false, and the truth is that the best type of workout, whether it's at home or in a gym, depends on you and how motivated you are to stick to your exercise goals.

As always, these exercise myths just scratch the surface. There are lots of other commonly held beliefs about exercise that are questionable, if not completely false. Research into many myths is ongoing, so scientists and doctors have the ammunition they need to tell their patients and the public how to get the most from their workouts without harming themselves, or getting frustrated and giving up. We hope we've helped clear up some of those myths for you, so you can get back to your workout with confidence.

If you stumble onto some indredulous claim about exercise, remember the tips from the end of our first food myths post to debunk it yourself — look for studies to support the assertion, or at least reputable sources with cited experts who can be tracked down. There's a lot of confusing information about exercise out there, and a sceptical eye (and a willingness to acknowledge you might be wrong) goes a long way.

Do you have some favourite exercise myths we didn't cover here? Share your thoughts — and your myths — in the comments below.

Dr Brian B. Parr is an Associate Professor in the Department of Exercise and Sports Science at the University of South Carolina Aiken. He is an American College of Sports Medicine (ACSM) certified Clinical Exercise Specialist and has his own blog where he writes about exercise, nutrition, and health issues.

This article has been revised and updated.