Forgetting to Rehydrate and 5 More Terrible Mistakes You're Making After a Workout

Step away from the box of cookies or Halo Top post-workout, though you can always get some a few hours later for dessert or a sweet treat.

"One of the worst things you can eat after a workout is junk . . . and by this I mean food with little to no nutritional value," certified personal trainer through American College of Sports Medicine (ACSM) Hope Pedraza told POPSUGAR.

"Because you are creating tiny tears in your muscles during a workout, you must repair this damage and help your muscles grow by refueling with carbs and protein. An easy post-workout snack is a protein shake. Mix this with something like rice cakes or fruit to get some quick-burning carbs to go right to muscles that need repair the most," she recommended.

Whether your workout is in the morning or at night, you need to get enough zzz's for your body to function and your muscles to repair and grow.

"Your body goes into recovery mode when you sleep, sending the nutrients and minerals your muscles, tissues, and bones need to repair themselves," Pedraza said. "Not only do you feel tired and sluggish, but your body hurts!" she said. Without it, your cortisol levels will be spiked, stressing your body out. Sleep helps quell cortisol to relax the body, so she recommends seven to eight hours nightly for decreased soreness and alertness come morning.

Think of all the sweat you're pouring out during a workout. Your body loses tons of electrolytes and fluids through exercise, so it's a huge mistake to not rehydrate when you're low.

"Even though it feels counterintuitive to take in calories after you've just burned them off, not eating or drinking after a workout puts your body at risk of going into 'starvation mode,' which means your metabolism will slow down and you'll hang onto water weight, which is the opposite of what you want," said Milan Costich, celebrity boxing trainer and the owner of Prevail boxing in West Hollywood, CA.

"Hydrate before, during, and after your workout to get the maximum benefit of your post-workout metabolism boost," Costich said. This can be water, coconut water, a smoothie or protein shake, tart cherry juice, or even homemade Gatorade for electrolytes.

Sure, if you have an injury or you're particularly sore after lower-body day in your HIIT class, it might make sense to take anti-inflammatories, like ibuprofen, to mitigate the pain. If you're popping pills like they're candy every night to deal with chronic soreness or to avoid feeling tired during your workout, though, it's a problem.

"If you find yourself relying on pre- or post-workout supplements or anti-inflammatory medicines, it's a great opportunity to take a step back and reevaluate your diet, lifestyle, and workout routine," Costich said.

Is there a gap in your diet leaving you nutrient deficient in certain areas? Are the workouts you're doing too hard on your muscles or joints? Are you skimping on sleep? "The goal is for working out to have a positive impact on your well-being, physically and mentally, so if what you're doing isn't working for you, it's never too late to switch it up," Costich said.

If you're jumping from boxing class in the morning to a run in the evening, and then again at boxing come morning, you might not be giving your muscles enough time to fully repair and rebuild damaged tissue. "One of the worst things we see clients do is overtrain by going straight from one workout to another," Costich said.

"When we're only after those quick results, we tend to do too much in too short of a time frame, often leading to injury or imbalance. Rather than burn yourself out, we believe in a more sustainable lifestyle of long-term commitment and consistency to help you feel your best and see even better results," Costich said.

It is fine to work out twice a day, though, as long as you're doing it the right way.

"A good post-workout stretch will help your body get the maximum benefit of your exercise. Stretching keeps your muscles from contracting, which will better allow them to rebuild after your workout," Costich said. "Over time, stretching will also help increase your mobility and range of motion, which will really give you an advantage in your future workouts — you'll be able to improve your form, perfect your technique, and push even harder with less risk of injury."