This training article was written by Cycling-Inform for L’Étape Australia by Tour de France.

While many people believe that muscle cramps are caused by dehydration, there is growing evidence that this may not be the leading cause.

What causes muscle cramps?

The most held belief is that muscle cramps are brought on during exercise because of dehydration. The main reason is that when you sweat, you lose fluids which include electrolytes (salt, potassium, magnesium, and calcium). There is some evidence that if you consume a sports drink containing sugar or eat during exercise that lasts more than two hours, it improves endurance performance and reduces that chance of developing muscle cramps.

These electrolytes are used to help the chemical firing of muscle fibres. When these nutrients in your body fall, the incidence of muscle cramps increases. It is reasonable to then link electrolytes to cramps and why many sports drinks now include these nutrients; salt, potassium, magnesium and sometimes calcium to reduce the chance of muscle cramps while cycling.

However, recent researchers found that those who suffered muscle cramps had the same level of dehydration and blood mineral levels as those who did not get muscle cramps. So, this belief is slowly becoming less important, and the search for the reasons for muscle cramps continues.

So, what can you do to reduce the chance of muscle cramps?

Recent research suggests the following to help reduce or delay the onset of a full-blown muscle cramp when the signs of muscle cramps start:

  • It has been suggested that muscle stretching is the best way to treat muscle cramps. I’m yet to find what they mean by this and if post stretching or stretching during exercise is the best method. In my experience, stretching during your rides is the best method to release a cramp.
  • Also, the ongoing conditioning of the muscles to avoid them fatiguing too soon during your rides.
  • Reducing the intensity or stopping cycling helps.
  • Ongoing regular massage.
  • Proper warm-up before going out on your cycle training ride and cycle racing.
  • Post-exercise stretching after your cycle training ride and cycle racing.
  • Being well hydrated with a good quality electrolyte sports drink during your cycle training ride and cycle racing.

My conclusion to the cause of muscle cramps

I believe that there may still be a case for electrolyte depletion and dehydration playing its part in increasing the chance of muscle cramps, but I also think that this is only part of the story. There are other reasons that a cyclist may develop muscle cramps, and that muscle fatigue is a highly likely candidate.

Regardless of the current theories, I still believe that being well hydrated with an electrolyte sports drink is important to ensure that the cyclist does not become severely dehydrated or run out of carbohydrate when cycling for events longer than two hours. By consuming a regular supply of carbohydrate during the ride, the likelihood of “hitting the wall” or “bonking” is significantly reduced, and performance can continue to be maintained.

I also believe that most muscle cramps are more likely to do with the cyclist’s conditioning. Regardless of the theories, a cyclist that has correctly prepared themselves for an event will be less likely to affected by muscle cramps.


While known medical causes of muscle cramps are still being researched, the occasional muscle spasm or muscle cramps is not deemed serious. However, if your muscle cramps are severe, frequent, constant or of concern, then make an appointment to see your doctor.