This blog post is courtesy of our guest blogger, Dr. Sheri Colberg.

How often have you heard certain things about physical activity and exercise training that you thought sounded correct, but found out later were totally wrong? If you hang out at a gym or even talk with training coaches, you’ll hear just about everything, including contradictory statements about the right ways to stay active.

Should you work out in a “fat burning” range? Will weight training make you bulk up? Will your muscles turn to fat if you stop working out? Do you need to eat a lot more protein to get bigger muscles? Confused? Here is the truth about some of the more common myths you’ll hear about being active.

Myth: Exercising regularly makes you more tired.

Although you may feel somewhat tired during a workout, once you’ve recovered, you usually feel more invigorated, not less. Doing any regular physical activity is guaranteed to raise your overall energy levels and make you better able to undertake life’s challenges. If you’re having trouble concentrating at work or getting too stressed, it helps to take a short walk or do any type of physical activity to clear your mind, bump up your energy levels, and decrease your mental stress. Doing regular physical activity also helps you sleep better at night, leaving you more refreshed and energetic during the day.

Myth: If you want to lose fat, you have to work out within a “fat burning” range.

Exactly what is the “fat-burning” range you see on a lot of aerobic exercise machines? You have to understand which fuels your body uses during rest and exercise. Typically, during rest 60% of your energy needs are supplied by fat (stored or eaten), with the other 40% coming from carbohydrates. As soon as you start to do any type of physical activity, though, carbs become a much higher percentage of your total energy supply. In fact, when you’re doing just moderate aerobic exercise like brisk walking, you’ll use very little fat, so you’re burning mostly carbs, even when you’re in a so-called “fat-burning” range. During more vigorous exercise, your body can’t use fat effectively, so almost all energy is supplied by carbs when you’re working out hard. You do use slightly more fat at a lower intensity, but fat is mostly used during your recovery from exercise, so just try to expend as many calories during exercise as possible without worrying about what types of fuels are supplying them.

Myth: When you don’t use your muscles, they turn into fat.

Have you ever looked at someone who used to be fit and thought that his or her muscles had really turned into flab? While there is no discounting the change in appearance, it is physically impossible for inactive muscles to turn into fat. What is really happening is this: when you work your muscles out regularly, they may increase in size or simply look more toned; if you stop using them, the muscle fibers will atrophy and disappear—similar to what happens to many people with aging. As your muscle mass decreases, your caloric needs also decrease, and if you don’t start eating less, you’ll gain fat weight that is stored under your skin (among other places). The reverse is true as well. If you drop body fat, your muscles will look more defined simply because there is less fat to cover them up. The bottom line is that it is never good to lose muscle mass, but if you don’t gain fat weight as you lose muscle, you’ll just look thinner without acquiring a flabby appearance.

Myth: Weight training will bulk you up.

This myth probably arose because you may look bigger as your muscles expand with heavy weight training. Women are especially worried about bulking up and getting bigger arms or legs. Remember how losing muscle can make you look thinner if you’re not gaining fat at the same time? Well, the same applies here, only in reverse. If you’re losing fat all over (including from under your skin) while you’re gaining muscle mass, you’ll stay about the same size. If you gain muscle without losing fat, you may look slightly bigger, or simply more toned. Either way, most people don’t gain enough muscle from weight training to ever look bulked up. More likely, you’ll just look more toned. When you first start exercising, your weight may go up slightly or just not come down as quickly as you think it should, simply because as you gain muscle while losing fat, the heavier of the two (muscle) will keep your scale weight higher. Focus less on your scale weight and more on your measurements and how well your clothes fit.

Myth: No pain, no gain.

If you’ve ever hung around a gym, you’re sure to have come across this myth. The “pain” part of exercise results from the build-up of acids in active muscles (like lactic acid), and acids drop the pH of your muscles and sensitize pain receptors. Usually, it’s just a sign that you’re working hard or that your muscle is fatiguing. However, you can certainly have gains in your strength and endurance without pushing yourself to the point of pain in the process. The more fit you become, the more easily your body can clear out those excess acids produced by physical activity. Too much pain can also signal that you’re likely to get injured.

Myth: Lifting weights slowly builds larger muscles.

Remember how we just debunked the “no pain, no gain” myth? If you try lifting weights more slowly, you’ll certainly feel the pain, but it absolutely doesn’t mean that your muscle or strength gains will be greater. On the contrary, lifting weights slowly when you could lift them faster will build more muscular endurance, while lifting the heaviest weight as quickly as possible will recruit extra muscle fibers and cause you to build bigger muscles. So, the rule of thumb should be that if you are lifting a weight slowly, but could lift it faster, you either need to move it faster or try a heavier weight for optimal results.

Myth: Working on your abdominal muscles will give you a flat belly.

You’ve probably always heard that if you want to get rid of that stomach flab, you have to do a lot of abdominal work, but don’t be fooled into believing that. As much as we’d all like to pick and choose where we lose our fat, it is not possible to spot reduce, and doing hundreds of crunches will not make you lose stomach fat any faster than you lose it from the rest of your body. If you want a flat belly, you can certainly work on toning up your abdominal region, but focus more on simply burning off excess calories. Doing harder workouts will also build more muscle, and having more muscle increases your daily caloric needs. One side benefit of including abdominal exercises, though, is that having toned abs makes it easier for you to pull in your stomach so it appears flatter, even if you can’t spot reduce there.

Myth: The more exercise you do, the better off you’ll be.

There is a limited benefit to anything, and that includes excessive exercise. When you do more than 60 to 90 minutes of aerobic exercise daily, you’re much more likely to develop overuse injuries—such as stress fractures, tendinitis, bursitis, and other joint issues. You don’t want to get injured because you will have to stop working out while you heal. You are better off doing slightly more intense exercise for a shorter period of time, which you can do with any type of interval training (including some of the latest crazes like HIIT and CrossFit). You can push yourself a bit harder from time to time during a workout, or do the whole thing at a higher intensity if you can, while cutting back on your duration—and you will gain the same benefits, or even more, from your workout. Most of us don’t have time to work out all day anyway, so it’s good to know that we really don’t need to.

Myth: If you want to gain muscle mass, eat more protein.

Ah, yes, the protein myth. It is true that you have to eat some protein to gain protein (muscles are made of amino acids, the building blocks of protein). And, yes, physically active people do need more protein that sedentary folks, but not that much more. In fact, no training athlete needs more than 1.6 to 1.7 grams of protein per kilogram of body weight (~0.75 grams per pound), which is just twice that of a sedentary person. Does that mean you need to take protein supplements or up the protein in your diet? Not usually. Most Americans already eat well over 15% of their calories as protein: about 75 grams of daily protein in a 2,000 calorie diet (or 112 grams per 3,000 calories), more than enough to cover protein needs. Taking in some protein (especially whey) with carbs right after hard workouts may be beneficial, but make sure your protein is coming from good sources without a lot of extra saturated or trans fats. Instead of spending money on supplements, try eating more egg whites or drinking chocolate milk post-exercise.

Myth: If you’re not sweating, you’re not working hard enough.

Everyone equates sweating with working hard, but that isn’t always the case. People vary in their sweating rates. Being physically trained improves your ability to sweat more and to start sweating sooner, but men always tend to sweat more than women. Sweating is related not only to exercise intensity, but also to the environment. If it’s hot and humid, you’re going to sweat more, even if you’re not working hard. You will also sweat less if you’re dehydrated or lose too much fluid while you’re working out, as your body has mechanisms to limit fluid losses to keep enough in your blood. So, sweating is often not reflective of your effort level.

Dr. Colberg is a renowned expert on diabetes and nutrition. To learn more about working with diabetic clients, check out “Essentials of Diabetes and Pre-Diabetes: Overview Program”, available in the W.I.T.S. store.

Sheri R. Colberg, PhD, is the author of The Athlete’s Guide to Diabetes: Expert Advice for 165 Sports and Activities(the newest edition of Diabetic Athlete’s Handbook), available through Human Kinetics (The Athlete’s Guide to Diabetes), Amazon (The Athlete’s Guide to Diabetes), Barnes & Noble, and elsewhere. She is also the author of Diabetes & Keeping Fit for Dummies. A professor emerita of exercise science from Old Dominion University and an internationally recognized diabetes motion expert, she is the author of 12 books, 28 book chapters, and over 415 articles. She was honored with the 2016 American Diabetes Association Outstanding Educator in Diabetes Award. Contact her via her websites (SheriColberg.com and DiabetesMotion.com).