13 Post-Gym Mistakes That Could Ruin Your Workout

Updated: May 20, 2021

These habits could sabotage your weight loss or make you more likely to get injured. Avoid them!

iStock/Tom Young

You reach for a sports drink

While it’s important to stay hydrated after a workout—even a 1 percent decrease in hydration can significantly impact your athletic performance—you probably don’t need a sports drink, which can contain unnecessary calories. You don’t need to replace electrolytes unless you’ve had an intense workout that lasted more than an hour, so plain water is probably sufficient, says Jessica Crandall, RDN, CDE, spokesperson for the Academy of Nutrition and Dietetics. “I just encourage hydration through water because that’s the best way to get adequately hydrated,” she says.


You skip the cool down

Stopping too fast could make you feel sick if your body doesn’t get the chance to recover. Your temperature rises and your blood vessels widen during physical activity, and your body needs the chance to get them back to normal, says Melissa Leber, MD, FACEP, assistant professor of orthopaedics and emergency medicine at Mount Sinai Hospital. “You can feel very light-headed if you don’t cool down and go straight to the shower,” she says. If you have a fitness tracker, make sure your heart rate is down to 100 or lower before you wrap up your workout. These are the 9 treadmill mistakes that make trainers cringe.


You don’t stretch

For the biggest gains in flexibility, stretch right after your workout. Because your muscles are already warm from the exercise, they’ll be able to lengthen more, so you can build a better range of motion. Stretching might not give you immediate injury protection, but your body will be better primed in the future. “It doesn’t prevent injury unless you’re looking down the road,” says Dr. Leber. “If the range of motion in your joints is better, you’re less prone to injury.” These are the 7 exercise mistakes that make you look older.


You wait hours to eat again

Refueling within two hours of a workout is crucial for recovery. Carbohydrates replenish the stored energy your muscles used, and protein helps repair the small tears in your muscles that exercise creates, says Alissa Rumsey, MS, RD, CDN, CSCS, spokesperson for the Academy of Nutrition and Dietetics. Aim for 15 to 20 grams of protein for prime recovery, says Crandall. “That protein, when it comes back in, is helping you replenish and re-heal that muscle so you get growth instead of being degraded,” she says. “If you’re not refueling, it’s breaking down further.”


Or you eat too soon

Exercise tends to suppress your hunger initially, but later in the day your hunger hormones will surge, says Rumsey. If you eat a snack within an hour of a workout just because you think you should, you might end up eating double. “That immediate post-workout snack is just additional calories,” she says. These are the common workouts that don’t burn calories.


You don’t look at your protein bar’s nutrition facts

Protein bars can be a convenient way to refuel after a gym session, but take a peek at the nutrition label before tearing into it—and look closely, because some have two servings in a single bar, says Crandall. “Sometimes protein bars can be really high in sugar and are glorified candy bars,” she says. Others use sugar alcohol as a sweetener, making them look lower in sugar, even though they can be bad for you too, says Rumsey. Your body can’t process sugar alcohol, so you might end up feeling bloated, crampy, or just plain unsatisfied. “It has a sweet taste, but there are no calories associated with it,” says Rumsey, “so the brain isn’t registering it, and we often crave more sweets later in the day.”


You head straight to the smoothie bar

Those smoothie bars seem like a convenient, healthy way to refuel, but steer clear—many are calorie bombs with two to four cups of fruit, not to mention sneaky sugar sources. “When juice is used as a base, it adds a lot of calories and also a lot of simple sugars,” says Rumsey. “What you’re drinking is similar to a soft drink.” For a post-workout drink that actually is as healthy as it seems, make your own smoothie using a cup of fruit, a handful of leafy greens, four to six ounces of plain Greek yogurt, and a handful of chia seeds or nuts, she says. These 7 common exercise moves actually work against you.


You reward yourself with food

After a day at the gym, you might find yourself ravenous and looking for an indulgent treat to reward yourself for a vigorous workout. But if you give in to those cravings, you could end up undoing all your hard work, says Crandall. After all, the 300 calories you burn in a 30-minute doesn’t exactly give you wiggle room for a free-for-all at the drive-thru. “You can’t outrun your mouth,” she says. “No matter what you’re doing from a physical fitness standpoint, it’s easier to eat than to work out.”


Or you try to make it an “extra-healthy” diet day

On the flip side, some people are so empowered by a great workout that they try to work harder on their diets by skipping meals and cutting too many calories. But your body still needs the fuel, so make sure you don’t go overboard with the calorie cutting. “On days you work out, don’t see it as a diet day—see it as a well balanced day,” says Dr. Leber. Instead of skimping on dinner, she recommends eating a well-rounded meal with four to six ounces of lean protein, a small serving of carbs like pasta or rice, and a vegetable. These are the biggest ab exercise mistakes people make.


You meet friends for post-workout drinks

If you’re heading to happy hour right after a gym session, you might want to stick to just one drink. Alcohol and protein are both synthesized in the liver, so heavy drinking could get in the way of your recovery after a workout. “When drinking a lot of alcohol, the liver is working to process the alcohol, and not the protein so much,” says Rumsey.


You rely on supplements

Supplements like protein drinks and vitamins can have a reverse effect if you overdo them. Vitamin overload could stress your immune system and cause degradation instead of healing. Get your protein and vitamins from natural food sources instead, which don’t have such large concentrations. “Food should be your first line of defense, and supplements are there for supplemental purpose only,” says Crandall. “If you go for food sources, you won’t overdo it.” Don’t miss these 12 common vitamin mistakes everyone makes.


You immediately schedule another workout every day

Turns out there is too much of a good thing, and physical activity is no exception. “Everyone thinks more is better, and that’s not necessarily true,” says Crandall. “That’s not how muscles work or how the immune system works.” If you don’t leave time for recovery, your muscles won’t have time to repair and heal. Switch up your workouts so you aren’t using the same muscles at every gym session, and schedule days with lighter workout, like taking a walk.


You pop ibuprofen for sore muscles

Some researchers believe taking ibuprofen after a workout could hinder protein synthesis, slowing down your body’s ability to build muscle. While the studies aren’t conclusive, try to avoid using painkillers routinely for everyday soreness. “I wouldn’t take it every day unless you’re treating a specific injury,” says Dr. Leber. These are the 8 group fitness class mistakes that render your workout useless.