6 Common Fitness Myths, Debunked by Pros

You should exercise intensely every single day.

Yes, it's important to maintain an active lifestyle and get up and move throughout the day, but it's equally important to rest and allow your muscles to recover from high-intensity workouts. "You should have at least one rest day to recover," Cervantes says. "Rest includes sleep. It's a huge part of your recovery. It's only the time of day your body is completely resting."

If you're waking up in the wee hours—or staying up late—to squeeze in your workout, Cervantes says it might be wise to rethink your routine and find ways to compromise. For instance, instead of working out for an hour, you can sleep for an extra 30 minutes and work out for 30. "Listen to your body," says Cervantes. "You want to be rested to perform optimally."

The longer the workout, the better.

Speaking of workout length, it's easy to think that the more hours you log at the gym, the better the workout you get. But sometimes less is more. Cervantes says it really comes down to how you exercise and what you're looking for. If you can get a really intense, efficient HIIT workout in 30 to 40 minutes, that can be more effective than spending two hours lifting weights or doing moderate cardio at the gym.

You have to eat within 30 minutes after a workout.

"Refueling is important. Your body is really vulnerable and soaks up nutrients like a sponge," says Cornell. "The 30-minute window is ideal, but it's really 30 to 90 minutes." So you do need to eat and refuel after a workout, but it's not the complete end of the world if you miss that 30-minute window.

The key is to eat a mix of carbs and protein to help with muscle protein synthesis and prevent muscle breakdown. Mascha Davis, RDN, founder of Mini Fish and author of Eat Your Vitamins, recommends aiming for 15 to 25 grams of protein within an hour after the workout. Some of her favorite post-workout meals are a Greek yogurt bowl, egg or turkey sandwich, fruit and protein smoothie, or grilled chicken wrap.

Strength training will make you bulky.

The fear of bulking is one of the most common misconceptions Cervantes hears. While many women tell him they're afraid to increase the weights they use because they think it will cause them to look bulky, Cervantes reassures that it's not that simple.

On the contrary, by adding weights to your routine, he says you can enjoy the benefits of building lean muscle and burning fat. Studies have also shown that resistance training can help preserve bone mass, which can help prevent osteoporosis.

For an easy way to start strength training, Cervantes loves HIIT, or high-intensity interval training, because it combines both cardio and weights, leading to increased heart rate and an after-burn effect.

You should do static stretches before a workout.

While it's true you want to stretch pre- and post-workout, there's a distinction in the types of stretches you should be doing before and after. Many of us probably remember being told in gym class to touch our toes before running the mile. Turns out, this type of static stretching before a workout, where you hold a position for a few seconds, is a common stretching mistake and can actually lead to more harm than good.

"You should always do static stretching after working out since your muscles are warm. But if you pull your muscles when they're cold, they're going to snap, sort of like a cold rubber band," says Cervantes.

Instead, Cervantes says to do dynamic stretching before your workout to get the muscles warm. Think of movements like a light jog, arm swings, jumping jacks, or high knees. These movements stretch the muscles to their full range of motion and emphasize mobility.

You need an expensive membership or equipment.

From Peloton to the Mirror, today's at-home workout gadgets can add up—but gym memberships are also pricey. However, leading a healthy lifestyle doesn't have to be so expensive. If you're just starting your fitness journey, Cervantes recommends finding ways to make fitness a part of your lifestyle, rather than investing in expensive and complicated equipment.

Saving money on your fitness can mean taking more walks during the day or turning brunch dates with friends into hiking or biking. You can also watch free yoga workouts on YouTube or sign up for virtual exercise classes offered by many fitness studios and apps. Plus you can find plenty of affordable workout equipment online (or just use items around your home!). "The goal is to find a long-term solution and a sustainable lifestyle," says Cervantes.