Why Do Leg Cramps Occur?

You can get leg cramps if you stay too long in the same posture, because of electrolyte problems, or due to neurological diseases, among other causes. In this article, we'll explain the most common causes and how to avoid them.
Why Do Leg Cramps Occur?
Leonardo Biolatto

Written and verified by the doctor Leonardo Biolatto.

Last update: 27 May, 2022

You’ve probably suffered from arm or leg cramps many times throughout your life. But why do let cramps occur?

Cramps are involuntary and sudden muscle contractions that cause pain. It’s estimated that almost half of the population suffers from them.

Normally, cramps are temporary and benign. However, they can even prevent the affected muscle from moving for a while. Although most disappear on their own, sometimes they can be a sign that something is wrong.

Leg cramps are the most common. They usually manifest at night, causing the sufferer to wake up suddenly due to the pain. Although the causes are varied, it’s known that their incidence increases with age and that they tend to affect women more than men.

Because many people suffer from them, we’ve decided to explain the main reasons why leg cramps occur and what you can do to prevent them.

Why do leg cramps occur?

Leg cramps can have many possible causes. In fact, scientists are still trying to discover the exact mechanism that causes them and the situations that trigger them.

However, they do know of some situations that are notably related to leg cramps. First of all, researchers suggest that episodes of tiredness and muscle fatigue after exercise often occur.

A jogger with cramps in his leg.

Another common reason is spending a lot of time lying down or pressing leg muscles in certain positions. This explains many of the cases that manifest in the early hours of the morning.

Leg cramps are also related to the activity of motor neurons, which are responsible for stimulating muscle movement. Thus, they also occur with certain neurological diseases, such as Parkinson’s disease. Likewise, experts know that certain drugs increase leg cramps. In fact, it’s a significant side effect of cancer treatments. Almost 80% of patients treated for cancer suffer from them.

It’s important to note that the most common cause of leg cramps – and, at the same time, the easiest to fix – is dehydration or the alteration of the concentrations of certain electrolytes in the blood. Both situations often go hand-in-hand.

Patients who are undergoing hemodialysis often experience leg cramps. This is related precisely to this electrolyte imbalance in the blood. For example, the case of potassium. Furthermore, it seems that vascular diseases, such as blockage of the coronary arteries or certain vessels of the legs, are also related to these cramps.

A person massaging another person's leg.

How to prevent or relieve leg cramps

Depending on their cause, leg cramps can be prevented or relieved. They usually last about nine minutes and also tend to repeat at the same time of day or during the same night. Thus, when they’re very common, people who suffer from them may end up suffering from insomnia.

The first step to preventing them is to try to move frequently and avoid staying in the same position for a long time. Also, experts recommend doing stretching exercises during the day or just before bedtime. The cold has also been linked to leg cramps, meaning that it’s best to stay in a warm environment. Once they appear, you can try to relax the area by massaging the affected muscle.

However, the truth is that there’s no medical treatment to prevent them. Some medical professionals recommend certain vitamin supplements or sodium or magnesium supplements. However, they haven’t been proven effective as of yet.

This article may interest you: How to Relieve Muscle Cramps


Leg cramps are very common and may be caused by many different things. Experts don’t exactly know why they occur and how to treat them. Ideally, if they occur repeatedly, you should consult a doctor to rule out that they’re associated with another condition.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.