Peloton member stretching to warm up, reducing muscle cramps

How to Prevent Muscle Cramps from Derailing Your Workout

Uncomfortable at best and painful at worst, cramping can turn a good workout into a bad one, fast.

By Jessica MigalaJuly 26, 2023


There are some things that can tank an otherwise good workout: sudden rain, stomach distress, feeling like your legs are especially sleepy today. Another exercise interrupter? Muscle cramps.

It’s tough when you’re in the zone and suddenly you feel a painful cramp that requires you to take a pause. It’s happened to most of us, but some people deal with muscle cramps way more often than others. If that’s you, here’s how to handle a spasm in the moment and how to prevent them from happening again. 

What Causes Muscle Cramps During Exercise?

First, let’s talk about what a muscle cramp is. According to the American Academy of Orthopaedic Surgeons, “a muscle cramp is an involuntary contraction of a muscle that occurs suddenly and does not relax.” That can cause light discomfort (why is my leg twitching?) to more intense pain lasting for a few seconds to 15 minutes or longer, says the Academy. You may also be able to see your muscle cramping.

Muscle cramps and muscle spasms are often used interchangeably, but cramps tend to last longer and be painful.

Several factors can set the stage for a cramp, including:

  • Dehydration: Dehydration and muscle cramps go hand in hand. Inadequate hydration stymies blood flow, and blood flow is necessary for proper muscle function because it carries nutrients and oxygen to working muscles and helps remove waste from the muscle, according to the University of Rochester Medical Center. “If you don’t have enough fluid in the body, your body will shunt whatever fluid it does have to your working heart and brain,” explains Balu Natarajan, MD, founder of Chicago Primary Care Sports Medicine and provider at The Running Institute. In other words, your body will prioritize your fluid needs to vital organs—not your legs. “Your body is trying to make sure you don’t pass out or faint,” he says. While that’s great for your health overall, it’s one frustrating reason why we get muscle cramps after heavy exercise.

  • Heavy sweating: You lose electrolytes through sweat. Electrolytes are minerals—calcium, chloride, magnesium, phosphorus, potassium, and sodium—that carry an electric charge and affect both your hydration and muscle function, according to the National Library of Medicine. Sodium is one of the main electrolytes of concern in exercise—and some people also sweat salt more than others, putting them at an increased risk for muscle cramping, says Dr. Natarajan. “They are what we call salty sweaters,” he says. Another key electrolyte for muscle function? Potassium, which can also be lost through sweat. To a less extent, magnesium is also excreted through sweat.

  • Weather: High heat or humidity is a double whammy here, as stifling temps are more likely to cause excessive sweating that can lead to dehydration and a loss of electrolytes, says Dr. Natarajan.

  • Not enough fuel in the tank: If you’re not eating enough—or not eating a balanced diet—you may also be at a higher risk. “There are a series of chemical reactions that occur to get one muscle to move, and these processes require a combination of carbohydrate, fat, and protein to work,” says Dr. Natarajan. 

  • Muscle fatigue: Whether you haven’t fully recovered from a prior workout, you’re going long and hard, or it’s just one of those days, muscle fatigue can lead to a cramp. “When a muscle is fatigued and tries to relax, sometimes the natural tendency is to contract instead,” says sports dietitian Amy Goodson, RD, CSSD at The Sports Nutrition Playbook.

The above are all factors that contribute to cramping during exercise. But what about muscle cramps after exercise? This type of cramping is more related to muscle tightness, injury, and lack of electrolytes, Dr. Natarajan says. The good news is, you can get muscle cramp relief from both types of cramping with the tips below.

How to Prevent Muscle Cramps During Exercise

When you’ve been through a muscle cramp once, you’re going to want to figure out how to get rid of muscle cramps and prevent them from happening again. What’s more, cramps are generally unpredictable—you don’t know when it’s going to happen to you, suggests research. And while you may not be able to ensure you can stop all muscle cramps, you can certainly decrease your risk—here’s how:

Train Progressively 

Even if you don’t have a race or event on the calendar, if you’re going on a ride, swim, or run, start with a shorter duration or distance and work up from there.

“Don’t go from zero to running a 10K,” Dr. Natarajan says. “The purpose of training is for your body to learn how to—for example—run a mile and then run two miles. It’s important to ease into physical activity,” he says. So, follow a training plan and make sure that you’re also building in rest and recovery days.


If you do have an event on the horizon, practice in conditions that will mimic what you’ll experience in the race or event. “Practicing is a big deal for prevention,” says Dr. Natarajan.

For instance, that’s doing short and long runs in the summer heat as you build mileage, rather than taking them indoors to a gym treadmill where there’s air conditioning. Your body needs time to get acclimated to the environment. (These tips can make the transition from treadmill to outdoor running easier.)

Warm-Up Right

Get your muscles prepped and ready for the work ahead. That can be something as simple as walking or doing some muscle activation exercises. For more formal warm-ups related to your sport, the Peloton App has five- and 10-minute warm-ups you can do before a run, ride, or strength workout. Unfortunately, some research shows that stretching prior to a workout doesn’t decrease the risk of cramping during a workout, per a very small randomized controlled trial in the journal Muscle & Nerve. While it may not be a preventative, stretching, however, can help to relieve cramps in the moment.

Eat Something Beforehand

If you go into a workout under-fueled—meaning you don’t have much in the way of carbohydrate stores—“you run the risk of being low on energy, which can make muscles fatigue faster,” says Goodson. Not everyone will need a pre-workout snack (like if you’ve recently had a meal), but if you haven’t eaten in several hours, having a small snack like yogurt and fruit or a piece of whole grain toast and nut butter can get the job done.


Drink up! “My recommendation is to divide your weight in pounds by two and drink that many ounces of fluid per day,” says Goodson. Also, keep in mind that everything from water, sports drinks, smoothies, tea, and chocolate milk all “count” as fluid.

If you think you may not be hydrating properly for exercise, get all the details on how to hydrate before, during, and after your workout. Here’s a quick summary:

  • Drink 16 to 24 ounces of fluid around two hours before exercise. 

  • Drink another 8 ounces 15 minutes before starting.

  • Continue to hydrate with another 16 to 32 ounces every 30 to 60 minutes during exercise.

  • After exercise, rehydrate with 16 to 24 ounces of fluid.

If you’re exercising for longer than 90 minutes, in a hot, humid environment, or doing a two-a-day workout, Goodson recommends a sports drink that contains carbohydrates and electrolytes.

If your urine is pale yellow or clear, you are adequately hydrated, she says.

Get in Electrolytes

Sodium and potassium are the main electrolytes lost through sweat, says Goodson, though sodium is more often the culprit to cramping. If your workout clothes develop white streaks on them after exercise, you’re a salty sweater and should prioritize sodium, which you can get from sports drinks or a pre-workout snack.

Recover with Hydrating Food

Carbohydrates replenish glycogen in muscles (stored fuel) while protein helps rebuild muscles, says Goodson. Smoothies and chocolate milk are two examples that hit on both while also helping your body rehydrate. But make sure to get in something, rather than just sipping H20: “Water is a good hydrator, but not rehydrator. We really need protein, carbs, and electrolytes,” says Goodson.

How to Stop Muscle Cramps Fast

You’ve made the time in your schedule to exercise, whether you’re working out for general health or in pursuit of a specific goal, like a race. Either way, it’s disheartening when the whole thing goes south because you have a muscle cramp.

Unfortunately, the only thing you can do to stop a muscle cramp fast is to stop exercising. You don’t have to stop in your tracks—you can wait it out for a bit. “I tend to use the ‘half-mile rule,’ with running and the ‘one-mile rule’ with biking,” says Dr. Natarajan. He will keep going and push through the cramp for the half or full mile distance. If the cramp is not better or is getting worse, he will stop and walk. At that point, you may be able to walk it off, and you can decide if you start again or call it.

If you are in extreme pain (or anything else that makes you truly worried), you should listen to your body and stop sooner.

“Muscle cramps should dissipate as soon after exercise is over,” says Dr. Natarajan. If the pain or discomfort lingers, you can try stretching the specific muscle, which can help relieve tightness. If that still doesn’t help, Dr. Natarajan says you can take over-the-counter medication, such as acetaminophen (Tylenol) or NSAIDs like ibuprofen (such as Advil). Before popping one of these OTCs, it’s important to consider what else is going on with your health, he says. For instance, acetaminophen can cause liver toxicity if taken with alcohol, and NSAIDs can be tough on your kidneys if you’re dehydrated.

If muscle cramps are so painful they impact your ability to function throughout the day or they wake you up from sleep, something more may be going on, such as an injury or an underlying condition, such as thyroid or blood pressure problems and you should consult with your doctor.

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.


Level up your inbox.

Subscribe for a weekly dose of fitness, plus the latest promos, launches, and events.

By providing your email address, you agree to receive marketing communications from Peloton.

For more about how we use your information, see our Privacy Policy.