What Causes Muscle Cramps and How Can You Prevent Them?

Muscle cramps are involuntary muscle contractions that cause a sudden pain and can make it hard to move.

They are often associated with intense exercise, but can also happen if you’ve held a position for too long and a nerve gets pinched. For the purpose of this article, we’ll only get into the causes and management of exercise-related muscle cramps.

Muscle cramps are notoriously unpredictable, making them hard to study in laboratory settings. Exercise-associated muscle cramps are prevalent in endurance athletes, and research into this topic usually focuses on marathon runners or triathletes.

What Causes Muscle Cramps?

Muscle cramps can be caused by:

• Strain or overuse of a muscle (neuromuscular overload and fatigue)
• Pinched nerves
• Dehydration
• Electrolyte deficiency
• Lack of blood circulation to muscles

The reason for some cramps is still unknown, and the above causes are still being disputed. Studies researching muscle cramps have concluded that they are a complex phenomenon with many different contributing factors [1, 2, 3, 4], and there’s no one simple answer to try and fix or avoid them.

Some studies suggest that one of the biggest risk factors for muscle cramps is previous history of exercise-induced muscle cramps, as well as performing exercise at a higher intensity or duration [5, 6, 7].

For distance runners, the theory that muscle cramps are caused by dehydration has been disproven by a couple of studies, which found no differences in dehydration or electrolyte levels before, during, or after the race.

“There is a long history of folk remedies for treatment or prevention of cramps; some may reduce the likelihood of some forms of cramping and reduce its intensity and duration, but none are consistently effective,” a 2019 study published in Sports Medicine (Auckland, N.Z.) concluded.

Are Muscle Cramps Dangerous?

While unpleasant, muscle cramps are usually harmless and go away without intervention.

The NHS recommends seeking the advice of a doctor if your muscle cramps affect your quality of life, for example if they constantly disrupt your sleep, or if you suffer from any other symptoms such as numbness or swelling.

How Can You Avoid and Prevent Muscle Cramps?

There are no proven strategies to prevent muscle cramps, but the following practices could be beneficial:

• Be aware of your hydration: drink plenty of fluids before, maybe during, and after your exercise. Despite the studies mentioned above, it is entirely possible some people suffer from muscle cramps because of dehydration or electrolyte depletion, or that these two variables might play a role.  
• Be adequately prepared for your training session or event: muscle cramps might occur at the limits of your performance, so ensuring you’re well prepared for the event you’re about to undertake might reduce the risk of exercise induced muscle cramps.
• Continue strength training: strength training improves muscle balance and posture, which in turn can help your muscles relax and function normally. A 2020 study published in the Journal of Strength and Conditioning Research also found that the main difference between athletes who cramped and didn’t cramp during a world-class marathon was lower-body strength training.

The NHS recommends stretching and massaging the muscle during the cramp to ease the pain, but notes that most cramps go away without you doing anything about them.

Because the cause of muscle cramps is still disputed, at this moment it seems like the best way to treat muscle cramps may be stretching, and an auspicious prevention method may include efforts to delay exercise-induced fatigue [8].

A 2019 study researching causes, solutions and questions remaining about muscle cramping during exercise concluded that: “It seems likely that there are different types of cramp that are initiated by different mechanisms; if this is the case, the search for a single strategy for prevention or treatment is unlikely to succeed.”

People get cramps for all sorts of reasons, including injury, disease and medication side effects. The cause of muscle cramps might even have to do with your genes. For now, more research is needed to find the exact cause of muscle cramps and how they might be prevented.

Until then, your best bet to treat and prevent muscle cramps is probably trial and error.

Disclaimer: All content within this article is provided for general information only and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional.