General Medical Corner Nutrition

All You Need to Know About Calf Cramps

Who doesn’t know them, those nasty leg cramps? During the night or towards the end of longer endurance exercise the muscle contracts. This often happens completely unexpectedly for the athlete. But why?

The reasons for cramps as well as the ways to prevent them are manifold. Consequently, we need to differentiate between cramps during performance and cramps occurring while resting. Today’s blog is going to provide you with all you have always wanted to know about cramps in your calves.

Cramps while running


Sometimes, upcoming cramps announce themselves by slight contraction in the muscle. If you feel that, you should see it as a signal and react. Unfortunately, for many runners cramps do not announce themselves but they occur seemingly out of nowhere. For longer endurance performances, such as a marathon, there’s often a strong contraction in the calf area, so that, temporarily, continuing to run seems impossible.

muscle cramps 580
Running seems to be impossible when your calves are cramping

The reason for cramps during performances often lies in a lack in sodium (as opposed to magnesium, which is often assumed). This mineral is mostly lost through the process of sweating. Especially on hot days, when peoples’ sweat production is on its top, cramps are common. Depending on both the outside temperature and the individual and his/ her shape, the amount of sweat produced per hour can be as large as 1liter. 400 to 1,000 mg sodium are lost with each liter.


Cramps occurring during an endurance performance are best prevented by regular consummation of liquids and electrolytes. Depending on duration, on external circumstances and on the individual, the recommended dosage is between 400 and 800ml liquid, in combination with 600 to 800mg sodium/liter. Liquids free of added minerals are less easily absorbed by your body. If consumed in large amounts, such liquids can even constitute a hazard to your health and lead to a so-called hyponatremia.

Thus, for long and intense endurance performances, it is important that you either take some isotonic drink or that you, in addition to water, regularly provide your body with minerals in the form of gels, bars or salt pills.

In case of acute cramps you should lower your pace or even stand still, stretch the muscle in question, or even massage it with your hand a little. In most cases, however, providing your body with minerals will be the only way for you to continue running.

Isotonic drinks are suited to prevent muscle cramps

Night cramps


Night cramps often occur completely out of nowhere and they can happen in various intensities. Sometimes the sole lifting of the tip of the toe is enough to provoke a cramp.


The reasons for night cramps are manifold. For athletes, cramps at night mostly correlate with a lack in magnesium or with an overloaded muscle.


In case of night cramps you should pay attention to an increased consumption of magnesium. Especially rich in magnesium are walnuts and wholegrain products and oats. If this is not enough, try magnesium supplements over a certain period of time. However, contact a doctor first and have a blood test done. It is best to take the magnesium after training or in the evening before going to bed. Magnesium can have laxative effects, so do not in any case take it immediately before or during training.


LeniThis blog was written by Ingalena Heuck, sports scientist, former German Champion in half marathon and running.COACH Gold Coach.

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