Muscle cramps at night: causes, what helps and when to see a GP

A muscle cramp is an involuntary, sudden tightening of a muscle that causes sharp pain and can make it hard to move. The NHS explains that leg cramps happen when a muscle in the leg tightens and causes a sudden pain, and that they can happen at any time, although most people have them at night or when resting.

Typically you are woken by the calf knotting up, the foot pulling downwards and a hard, tight muscle that you can feel under your hand. Most cramps ease within a few minutes, but the aching can linger. Because they interrupt sleep, even short cramps can leave you tired during the day, which is why people often search for ways to stop them.

This guide is about ordinary night-time cramps. Cramps are different from restless legs, in which there is an urge to move the legs, and from twitching, which is a brief flicker of a muscle. If you are unsure which you have, a GP can help to tell them apart.

The NHS says stretching and massaging the muscle may ease the pain during a cramp, although most cramps go away without you doing anything. Standing up and putting your weight on the leg with the cramp may also help.

Paracetamol or ibuprofen can ease muscle soreness after a cramp, but the NHS notes they will not help while it is happening because they take too long to work.

• Stretch the calf by gently pulling the toes and foot upwards towards the shin.

• Massage the tight muscle with firm, slow strokes.

• Stand up and put weight on the affected leg if you can do so safely.

• Use paracetamol or ibuprofen for aching afterwards if they are suitable for you.

The NHS says regular calf-stretching exercises may help to reduce cramps, but may not completely stop them from happening. Its suggested routine is to stand facing a wall with arms outstretched so that the hands just touch it, keep the feet flat on the floor and lean forward, pressing the hands against the wall until the calf muscles stretch. Hold for 2 or 3 seconds, stand up straight again and repeat a few times for 5 minutes, 3 times a day, the last time just before bed. If the number of cramps reduces, you might only need to do the exercise once or twice a day.

The NHS also lists not drinking enough fluids and putting too much strain on muscles during exercise, which can be worse in hot or humid weather, among the causes. Keeping well hydrated through the day and warming up and cooling down around exercise are sensible steps that fit with those causes.

The NHS says the reason for some cramps is unknown. When a cause is found, it can include the following.

• Ageing.

• Putting too much strain on muscles during exercise, which can be worse in hot or humid weather.

• Pregnancy, usually in the later stage.

• Certain medicines, for example statins used to lower cholesterol and diuretics used for high blood pressure.

• Not drinking enough fluids (dehydration).

• Liver disease because of drinking too much alcohol.

The NHS recommends seeing a GP if your leg cramps are disturbing your sleep, if you also have numbness or swelling in your legs, or if cramps last longer than 10 minutes. These features suggest that more than a simple muscle problem may be going on, or that the cramps are affecting your health enough to warrant a review.

It is also worth mentioning any new medicine you started around the time the cramps began. Do not stop a prescribed medicine such as a statin or a water tablet without speaking to the prescriber, since the reason you take it still matters.

The NHS says a GP will examine you to try to find the reason for your leg cramps and will suggest a treatment depending on the cause. This might be stretching exercises or, if exercise has not helped, quinine tablets. The NHS notes that quinine is not suitable for everyone and that the GP will discuss potential risks and side effects with you.

NICE Clinical Knowledge Summaries, the guidance used by GPs, describes most night-time leg cramps as idiopathic, meaning no underlying cause is found, and says investigations are usually not needed unless the cramp has atypical features or an underlying cause is suspected. Its management advice starts with reassurance that such cramps are common and can resolve on their own, followed by self-care such as stretching and massaging the muscle, and painkillers if the muscle is tender afterwards.

NICE says quinine is generally not recommended for idiopathic leg cramps because of its poor balance of benefit to risk, although a trial may be considered in certain circumstances if self-care measures fail, cramps are frequent and quality of life is affected. It also says a specialist referral should be considered if the diagnosis is in doubt or treatment in primary care fails and symptoms are affecting quality of life.

The same guidance lists conditions that can mimic leg cramps, including claudication, restless legs syndrome, Baker's cyst, deep vein thrombosis and dystonia, which is one reason a GP examines the leg rather than assuming it is simple cramp. The NHS notes that restless legs syndrome, in which there is a strong urge to move the legs usually at night, is a different condition with its own treatment.

Night cramps are normally dealt with in primary care on the NHS, by a GP or sometimes a pharmacist or physiotherapist. Most people do not need a specialist. If a specialist opinion is needed, for example for nerve or circulation problems, the GP can arrange it. Some people see a private physiotherapist for stretching advice; this is a reasonable choice if you want hands-on guidance, as long as any new leg symptoms are also mentioned to your GP.