There are two main types of cramp: sports cramps and night-time cramps. Sports cramps are something even professional athletes can fall foul of, although we don't really know why they occur.
Like night-time cramps, they can range from a slight twitch to severe pain, and the cramped muscle can feel rockhard for anything from a few seconds to several minutes or longer. It is also not uncommon for cramps to ease up and then return several times before going away entirely.
Many fitness experts think cramps are related to poor flexibility, muscle fatigue or doing a new activity. Other factors include exercising in extreme heat, dehydration and electrolyte depletion.
Electrolytes are nutrients such as sodium or salt, potassium, magnesium and calcium, which are sweated out during exercise. When levels of these nutrients - important for everything from muscle movement to blood pressure - drop, you suffer more muscle spasms.
Sipping water (or an electrolyte-filled sports drink) is therefore vital throughout a training session.
Another time athletes are more likely to get cramps is in the pre-season, when the body is not conditioned. This is why cramps also affect less regular and slightly older gym users! Cramps often develop near the end of intense or prolonged exercise, or during the night afterwards. Most cramps aren't serious, but if they're severe, frequent or constant, then see your doctor.
Night-time cramps generally affect the legs ? especially the calves and feet. They occur more frequently in adults over 40 than in younger people (although children may experience crampy than in younger people (although children may experience crampy 'growing pains').
Again, the causes are not fully understood, however certain conditions such as iron deficiency, anaemia, smoking, hormone imbalances, varicose veins, arthritis, even atherosclerosis (blocked arteries) can all result in cramping and tend to be more prevalent in older people.
Medication such as diuretic drugs for high-blood pressure or heart disorders can cause cramps, as can poor circulation, so see your doctor to ensure everything is OK.
But if none of the above applies to you, your cramps could be down to an imbalance in the body's electrolytes - magnesium, calcium and potassium - and/or deficiency of vitamin E.
Heavy alcohol consumption can hinder the absorption of magnesium, so women should stick to two to three units per day fand men to three to four units as a maximum. To boost magnesium levels, try including more pulses, tofu, nuts, potatoes and oatmeal in your diet.
The recommended daily intake is 270mg for women and 300mg for men, which equates to 66g Brazil nuts or 110g pine nuts. Tap water can be a good source of magnesium if you live in a hardwater area. In any case, drink twoand-a-half litres of fluid a day to ensure good hydration.
Lack of calcium can also aggravate night cramps. The recommended intake for adults is 700mg a day, but I believe that the amount recommended in America - 1,000mg - is a better target.
This is roughly 200ml of milk, a small pot of yoghurt or a matchbox-sized piece of cheese. Nondairy calcium sources include leafy green vegetables, small-boned fish such as sardines, orange juice, cereals and nuts.
To boost your potassium intake, eat bananas, pulses, garlic and onions, and fruit and vegetables in general. Make sure your diet is rich in vitamin E - this includes vegetable oils, nuts, seeds, avocados and sweet potatoes.
Sometimes quinine - a treatment for malaria - can help. Quinine sulphate (200-400mg per day), available from chemists, can reduce the frequency of cramps. The benefit is cumulative, so it's thought to help if taken regularly.
However, the use of quinine is controversial. There are potential side-effects such as dizziness and blurred vision, so talk to your doctor first.
Finally, taking valerian root at bedtime may help to relax the muscles. The recommended dose is 300-500mg of root extract (available in a pill), or 5 ml of tincture, taken one hour before bedtime.
