Leg cramps wake me up at night. Am I lacking something?

Night leg cramps that jolt you awake usually do not mean your body is short of one particular nutrient. Often there is no clear cause, but age, hard use of your muscles, long periods of sitting or standing, pregnancy, some medicines and not drinking enough can all play a part. What you can do yourself is stretch and massage the calf when a cramp hits, stretch your calves regularly before bed, and if cramps keep disturbing your sleep, see a doctor to find the cause rather than guessing.

Night leg cramps are common. A review in American Family Physician says up to 60% of adults report having had them, and Cleveland Clinic notes that among people over 60, about 33% get a night leg cramp at least once every two months.

Leg cramps wake me up at night. What is my body lacking?

The honest answer is that, in most cases, nothing you can point to. The American Family Physician review says most leg cramps have no identifiable cause, and the UK's NHS says the reason for some cramps is unknown.

If anything is commonly "missing", it is water

The NHS and Cleveland Clinic both list not drinking enough as a factor. Thailand's heat, sweating through the day, and drinking less in the evening so you do not have to get up for the toilet can all leave you short of fluids without noticing. Drinking enough throughout the day is the simplest thing to get right.

Why look for the cause first?

The cause of most leg cramps is hard to pin down, so guessing at it yourself can mean missing what actually needs checking. If cramps disturb your sleep regularly, a doctor can ask about your routine and the medicines you take, examine you, and look for the cause with you.

Why do leg cramps tend to happen at night?

Cleveland Clinic describes night leg cramps as sudden, involuntary tightening of a muscle that tends to happen when you are not very active, such as when you are asleep. They usually affect the calf, foot or thigh. The NHS says a cramp brings sudden pain that can make it hard to move, lasting anywhere from a few seconds to 10 minutes, and the American Family Physician review gives an average of about nine minutes per episode.

Factors that can play a part

Heavy-leg days are often followed by cramps

Many people notice cramps come more easily on the night after a full day of walking around a new city, a longer run than usual, or a day standing at a market stall, in a kitchen or on a hard factory floor. That fits the factors of working your muscles hard and standing on hard floors. People who sit at a screen all day without getting up fit the long-sitting factor.

Pregnancy and regular medicines

The NHS lists pregnancy as one factor, and some medicines can also cause cramps. If cramps started after you began a new medicine, do not stop it on your own. Talk to the doctor or pharmacist who gave it to you.

What should I do when a cramp wakes me up?

The NHS says most cramps go away without you doing anything, but stretching and massaging the muscle may help with the pain while it lasts.

Stretch the cramping muscle

• Stand up and put your weight on the leg with the cramp, which the NHS says may help.
• If you cannot get up yet, sit with your leg straight and pull your toes towards you to stretch the calf.
• Stretch gently rather than jerking the leg.

Massage, walk and use heat or cold

• Gently massage the hard, knotted muscle.
• Cleveland Clinic suggests walking around and pressing your feet down into the floor.
• Use warmth or a cold pack, whichever feels better.

After the cramp has gone

The NHS says the muscle can stay sore for up to 24 hours, so your calf may still ache the next morning. If you take regular medicines or are pregnant, talk to a doctor or pharmacist before using any medicine.

What can I do before bed so cramps don't wake me up?

The NHS says regular calf stretches may help reduce cramps, though they may not stop them completely. Cleveland Clinic also suggests stretching your legs before and after exercise, and right before you go to sleep.

The NHS calf stretch

1. Stand facing a wall, far enough away to touch it with your arms outstretched.
2. Put your hands on the wall and keep both heels on the floor.
3. Lean forward until you feel the stretch in your calves.
4. Hold for 2 to 3 seconds, then come back.
5. Repeat for about 5 minutes.

The NHS suggests doing this 3 times a day, with the last session just before bed. If your cramps become less frequent, once or twice a day may be enough.

Your sleeping position and surroundings

Heavy bedding pressing on your feet can keep your toes pointed down all night. Try tucking it in loosely, or put a small pillow under the covers at the foot of the bed.

During the day

• If you sit for long periods, get up, walk and circle your ankles now and then.
• If you stand for long periods, shift your weight between your feet and sit down when you can.
• On days you exercise hard, stretch your calves afterwards, and build up intensity gradually rather than all at once.

If you can't get back to sleep after a cramp, see Can't sleep because your mind won't stop thinking?

How is a cramp different from other night-time leg feelings?

Cleveland Clinic separates the two. A cramp brings strong pain and a hard, tight muscle. A crawling feeling inside the legs that makes you want to keep moving them, without strong pain, is a different kind of problem.

If your night-time symptoms sound more like the second, or you are not sure which it is, describe them to a doctor.

When should I see a doctor?

The NHS advises seeing a doctor if:

• cramps are disturbing your sleep
• you have numbness or swelling
• a cramp lasts longer than 10 minutes

Cleveland Clinic adds that cramps that are unbearably painful, happen often or last a long time are also worth getting checked.

Note these down before your appointment

• how often cramps happen, at what time, and in which leg
• how long each one lasts
• what you did that day, such as standing for long, walking a lot or exercising
• all the medicines and supplements you take
• whether you are pregnant

This helps the doctor find the cause more accurately. Use any medicine only as advised by a doctor or pharmacist rather than starting it on your own.