“I have persistent problems with cramps, mainly at night. It is usually in my legs and feet and is really getting me down as I have to leap out of bed and stretch everything to get rid of it. It is waking me three or four times most nights now. I am desperate to find a cure for it. I have been taking magnesium tablets two or three times a day but it doesn’t stop it. Can you please advise me?”
Dr Sarah Jarvis says: “Muscles cramps are very common – up to 60% of adults get them at some point. They usually affect your lower legs and tend to be most troublesome during the night. Pregnant women are particularly prone to muscle cramps – clearly not relevant to you, John. But the research into their cause might be. It’s not known exactly why pregnant women get so many muscle cramps, but changes in the body salts, particularly calcium and magnesium, may play a role.
You’re quite right that low magnesium has been implicated in muscle cramps. Other medical conditions that affect your metabolism – chronic kidney disease, cirrhosis of the liver, underactive thyroid, low calcium, low or high potassium and low sodium can all bring them on.
Some medicines like diuretics (usually given for high blood pressure) and SSRI antidepressant tablets can cause low sodium in the bloodstream. Changes in your calcium levels can be linked to disorders of the parathyroid gland. Various diuretics and tablets called ACE inhibitors – used for high blood pressure and to protect your kidneys – can affect potassium levels. Other medicines including statins (for raised cholesterol), nifedipine (for high blood pressure or heart arrhythmias) terbutaline and salbutamol (used for asthma and the chronic lung condition COPD), raloxifene (for osteoporosis) and strong painkillers (opioids) can also cause cramps. Check with your doctor or pharmacist in case any of your medicines could be making your condition worse.
Diarrhoea, vomiting, over-exertion and excess sweating or alcohol can also cause cramps by affecting your sodium and potassium levels. However, most people don’t have any cause for their night cramps found. It’s thought that cramps might happen when an already shortened muscle contracts. Using a duvet rather than a sheet (to prevent your muscles being held in a cramped position); sleeping on your back with a pillow beneath your knees, to keep your muscles in a more relaxed posture; or putting a pillow on its side at the end of the bed to keep your toes pointing straight up might help.
You’ve mentioned stretching your muscles when you get cramps to get rid of them. You may find that stretching either before bed or regularly three times a day can help prevent them from happening. Stand about two to three feet from a wall, facing towards it. Keeping your feet flat on the floor, lean in gradually to the wall, so you can feel your calf muscles stretching. Alternatively, stand on a step with the back half of your feet hanging off the edge. Slowly lower your heels to stretch your calves, holding for a few seconds. Repeat the exercise for about five minutes, three times a day, doing the last exercises just before bed.
For severe cramps, quinine tablets taken regularly may help. However, they can cause side effects including headache, tinnitus and nausea. Very occasionally, they can cause your platelets to drop, making you prone to serious bleeding.”
̶ Dr Sarah Jarvis