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If you’ve ever suffered from a muscle cramp, you’ll know that they can be very painful. You will also know that they can last anywhere from a few seconds to a few minutes, and often seem to strike out of the blue.
In fact, most cramps occur while we’re sleeping, while we’re exercising, or while we’re relaxing in bed at night.
The good news is that most muscle cramps are rarely a cause for concern. It can be difficult to pinpoint the exact cause, but frequent triggers include:
There are many other causes of muscle cramps including pregnancy, poor circulation, side effects of certain medications and cirrhosis.
If you’re experiencing intermittent muscle cramps, you can read below about things you can do to help reduce the pain and relax your muscles.
If your muscle cramps last longer than 10 minutes then you should see a doctor urgently to exclude serious conditions. If you’re experiencing frequent muscle cramps, there may also be an underlying medical condition. A chronic electrolyte imbalance caused by a nutrient-deficient diet or intense exercise is one such possible cause.
Chronic liver disease or complications caused by certain medications may also be to blame. It is always worth seeing a doctor if you think that your muscle cramps may be linked to these conditions, as they will be able to diagnose the problem and treat the underlying cause.
You’ll find detailed information about some common causes of muscle cramps below, as well as strategies for treatment and prevention.
Heavy exercise can cause certain muscles to become ’overloaded’ or fatigued. This over-excites the nerves inside your muscles and stops the inhibitory responses that are designed to prevent sudden changes in muscle tension - triggering a sudden contraction or cramp.
According to research published in Current Sports Medicine Reports, this type of cramp tends to be very localized, which means that it will only occur in muscles that you’ve been using recently. Common examples include calf cramps while running or swimming; although it is possible for the muscles in your back, neck, arm, thigh or shoulder to cramp as a result of muscular fatigue.
Cramp caused by muscle fatigue tends to be caused by intense exercise. It is a natural consequence of muscle fatigue, and to be expected from time to time if you engage in frequent physical activity.
If you’ve been working out a lot recently or you’ve just started a new exercise regime, you may be prone to cramps caused by muscle fatigue. You may also find that certain types of exercise - including athletic exercise, swimming or cycling - tend to trigger this type of cramp more frequently.
Dehydration causes cramps because it upsets the delicate balance of electrolytes in your cells. This disrupts the transmission of electrical signals between the nerves in our muscles, and leads to the over-sensitization of the nerve terminals, triggering muscle cramps or spasm.
Muscle cramps caused by dehydration tend to be much more common than the cramps caused by muscle fatigue. They may also happen in the absence of physical exercise, and can affect muscles that you haven't used recently.
According to an article from the Best Practice Advocacy Centre (pdf) in New Zealand, dehydration is thought to be one of the main contributing factors in muscle cramps that occur while we are asleep or at rest - so if you find that you are frequently woken up by cramps in your legs, dehydration may be the cause.
Dehydration occurs whenever the body loses more water than it’s taking in. Short-term dehydration can be caused by excessive sweating, which tends to be triggered by intense exercise or hot weather. Failing to drink enough water can also make you dehydrated.
Chronic dehydration can occur when you force your body to function without water for an extended period of time. This condition - although much rarer than regular dehydration - can cause frequent and sustained muscle cramps.
Your nerve cells need a delicate balance of electrolytes to function correctly. These electrolytes - which include minerals like magnesium, sodium and calcium - play an important part in carrying electrical signals across cell walls.
When our electrolytes become imbalanced our nerves can become over sensitized, causing them to fire off in patterns that cause sudden cramps.
The cramps caused by an electrolyte imbalance tend to be widespread, and can occur at any time. They may be more frequent after exercise due to the fact that you will have lost additional electrolytes as a result of sweating, but they can also occur at night, or upon waking.
An electrolyte imbalance can be caused by a number of different things. Profuse sweating can cause a temporary electrolyte deficit, making exercise or heat exposure relatively common short-term causes. Prolonged vomiting, diarrhea, and certain medications can also cause a short-term electrolyte imbalance.
Long-term electrolyte imbalance can be the result of a serious medical condition like kidney failure or hypothyroidism, but poor diet or malnutrition is thought to be one of the more common causes. In fact, an article published in Science Daily states that approximately 50% of the American population is deficient in essential electrolytes like magnesium.
Certain medications can also cause muscle cramps. These medications - which include common prescription drugs like statins, medications with a diuretic effect, or medicines designed to alter your blood pressure - tend to interfere with the electrolyte balance in your body.
This over-sensitizes the nerves responsible for telling your muscles to contract, and causes intermittent cramping in a number of locations - but usually in the calves.
In the case of statins, research published by JAMA shows that cramps may also be caused by the overexpression of some coenzymes, like coenzyme Q10. This stops your muscles from respiring efficiently, and triggers the build up of lactic acid which is known to cause muscle cramps.
Several different types of medication are known to cause muscle cramps. The most common examples are:
If you’re concerned that your medication is causing muscle cramps you should talk to your doctor as soon as possible. They may be able to recommend an alternative, or help you to treat the cramps in another way.
You should never discontinue, or alter your dosage of a medication without consulting your doctor first.
Whatever the cause, all muscle cramps involve the involuntary contraction of a muscle in the body. As such, it should always be possible to alleviate the short-term symptoms of a muscle cramp by helping the muscle to relax.
The most effective relief will come from massaging the muscle group directly. To do this, simply press down on the affected area with your hand, and work your fingers back and forth until the muscle starts to uncramp.
Stretching the muscle can also help to provide relief. Simply fully-extend the muscle, and hold until the pain starts to fade. If you are suffering from cramp in your calf, it may also help to do standing calf stretches.
Finally, you can try applying hot or cold compresses to the affected muscle. This will also help the muscle to relax, and this should provide some relief from the pain.
The best way to prevent muscle cramps is to address any possible underlying cause, such as identifying dehydration or the possibility of electrolyte imbalance.
Stretching before you exercise can help to prevent cramping from muscle fatigue. Hydration is key in helping to ensure your body can maintain its electrolyte balance and therefore shield your nerves from damage.
Guidelines published by the British Nutrition Foundation recommend drinking between 6-8 glasses of water per day to keep your body hydrated. The body’s demand for water will increase with exercise, but there is no definite way to measure the amount of extra water you will need.
Try to be aware of signs like a dry or sticky mouth, a headache or dizziness, and drink more water or hydrating fluids whenever you begin to feel thirsty to ensure that you are well hydrated at all times.
If you are becoming dehydrated due to exercise, you could also drink a sports drink with added salts and sodium, although articles published in the BMJ show that there is no conclusive evidence to suggest that these drinks are healthier than water.
If you’re suffering from frequent cramping and you think it’s because of an electrolyte imbalance, drinking a sports drink with added salts and sodium may help to offset any short-term problems.
If you think you might have a chronic electrolyte imbalance as a result of your diet you should see a doctor immediately. They will be able to check the balance of minerals in your system and help you correct the problem safely.
Most treatment options include oral mineral supplements or a change in diet. Foods rich in minerals which can help to prevent muscle cramp include:
Your doctor may also screen you for some conditions that can cause electrolyte imbalance, such as kidney disease.
You can find out more about treating vitamin and mineral deficiencies in our Health A-Z
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.