You know the feeling: You’re in the middle of a run or a race and suddenly your muscles cramp up. Yes, it’s the worst. Not only do muscle spasms hurt, but they can continue to linger unless you nourish them ASAP. 

To ease the cramp and get back into running, you’ll need to fuel your muscles with the right nutrients fast, before it gets worse. This is why many endurance athletes carry sports gels, electrolyte snacks, and supplements on long runs and sessions. When you're going out for a long workout, your muscles are more likely to get dehydrated and depleted of nutrients. 

Related: Magnesium Helps Tackle Stress and Muscle Cramps. Here's How.

There are actually a few causes of muscle cramping, all of which can be managed through proper lifestyle habits. Sometimes cramps come on suddenly — while other times there are some warning signs — so pay attention to any cues you may see. 

For example, if your mouth gets dry or you feel excessive thirst, drink water with some electrolytes to hydrate and prevent the spasm from occurring. And as a general rule, drink plenty of fluids and don’t go too long without food during the day, as you’re more likely to experience muscle cramps without steady nourishment. Here are the main causes of muscle cramps, along with how to stop them from happening in the first place. 

Why Do Your Muscles Keep Cramping?

1. Your Body Needs Sodium  

“Contrary to what you hear about potassium and needing to eat a banana, when it comes to nutrition, muscle cramps are most often associated with inadequate sodium and dehydration,” Kelly Jones, MS, RD, CSSD, LDN, says. 

This isn’t to say you shouldn’t have potassium or a banana as a pre-workout snack — as you should, since bananas are high in fast-acting carbs for immediate energy and potassium is still a valuable electrolyte that your body needs to stay balanced. However, dehydration often comes from not having enough sodium in your diet, which is common among athletes and those training for a race. 

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“Many active individuals who aim to maintain a healthy lifestyle assume that salt should be reduced or avoided based on recommendations to the average sedentary American," Jones says. "But without enough, your body has a hard time maintaining proper fluid balance.

Related: 4 Natural Drinks to Substitute for Sugar-Filled Electrolyte Beverages

“This can mean excreting excess fluid or having a hard time continuing to pump fluid into the right places in and out of muscle cells during activity." 

Risk is even higher when exercising in the heat or for longer workouts of over an hour without replacing sodium.

“If you eat very few packaged foods, start adding salt to your recipes and even your smoothies,” she says. 

2. You’re Not Getting Enough Calcium 

In addition to sodium, calcium imbalances may be related to cramping, too.

“Calcium may be important for your bones, but is also involved in every muscle contraction in the body, where it flows into muscle cells for contractions and then leaves when the muscle relaxes,” she says.

Related: 6 Ways to Stay Nourished as a Vegan (Plus 3 Things to Not Worry About)

It's important to get enough calcium through food. Good sources include Greek yogurt, cottage cheese, kale, edamame, shellfish and fish, for example, and if you're taking a supplement, don't overdo it.

“Chronic excess intake can cause excess firing of the muscles,” she explains.

3. You're Not Eating Enough Carbohydrates

This is why many people on the keto diet have to monitor hydration, since dehydration can be a common side effect of low carbohydrate intake.

“This causes you to not have adequate glycogen (stored carbohydrates, or the most efficient source of energy at high intensities) in the muscles,” she says. “Each gram of glycogen holds on to about three milliliters of water, so without it you may not retain enough fluid for its functions in energy production and for fluid balance in the muscle cells."

Related: How to Choose the Right Carbs for the Right Race

While having quick-digesting carbohydrates before your training session is important, your total carbohydrate intake needs to be sufficient to maintain glycogen storage, so spread them out throughout the day.

4. You Don’t Spend Time Recovering Post-Workout

Aside from nutrition, muscle cramping may be associated with overuse or inadequate time to recover from a training session. It could even be the result of a lack of recovery for a specific muscle group.

Related: Are You Training Too Hard? Here's How to Know (and What to Do About It)

“If you're cramping often, ensure that you're taking a rest day each week and that you aren't training at a high intensity every day or overworking the same muscle groups,” she says. "This will give your body the time it needs to repair muscle damage."