What causes muscle cramps, and are there any cures?

We put this to Dr. Steven Huan, Ashley Montagu Fellow in the faculty of Education and Social Work at the University of Sydney...

Steven - A muscle cramp is an involuntary and forcibly contracted muscle that simply does not relax. When you use your muscles, you can control them voluntarily, in your legs and arms for example, and they can contract alternately, they can relax and then contract. But when you lose control of this, this is the muscle cramp. Now, about 95% of humans have muscle cramps, have experienced them at least sometimes, some more than others and it happens particularly in old age, but even children can have muscle cramps.

Now what do we do to prevent them? Well you have to be very careful about warming up before exercise, you have to be very careful that you don't become dehydrated. That's why, when you see for example, tennis players getting leg cramps, that's because they're losing a lot of fluid when they're on the tennis court, especially in very, very hot weather. So you have to remain hydrated.

You also have to have a high level of potassium in your body because if you have low potassium, sometimes this can cause the muscle cramps, but also, low potassium can be associated with muscle weakness as well.

Diana - Sometimes, muscles over-shorten themselves and this can be caused by low sodium, low potassium, dehydration, hypoglycaemia, and even hypocalcaemia, which is a lack of calcium. So, maybe try having a drink and something to replace whatever nutrients you might be missing. While sometimes it happens because the joint has been flexed too much and you just have to straighten it out or walk it off.