Drinking electrolytes instead of pure water can help prevent muscle cramps, new research from Edith Cowan University (ECU) has found.

The study is one of the few experimental investigations of cramp during exercise – and the findings are supported by anecdotal evidence and observational studies.

It’s a worthy research topic given that “around 39 per cent of marathon runners, 52 per cent of rugby players and 60 per cent of cyclists” experience painful cramps during and after activity.

But the link between electrolytes, dehydration and cramp continues to be a matter of debate.

A personal inquiry

Lead researcher Professor Ken Nosaka, from ECU’s School of Medical and Health Sciences, in a prepared statement said that many people think dehydration causes muscle cramps “and will drink pure water while exercising to prevent cramping”.

But the researchers found that “people who solely drink plain water before and after exercise could in fact be making them more prone to cramps”.

This was likely because “pure water dilutes the electrolyte concentration in our bodies and doesn’t replace what is lost during sweating,” Professor Nosaka said.

Professor Nosaka said he began researching the causes of muscle cramps after regularly suffering from them while playing tennis.

The sweaty experiment

According to a statement from ECU:

• The study involved 10 men who ran on a downhill treadmill in a hot (35ºC) room for 40 to 60 minutes to lose between 1.5 and two per cent of their body weight through sweat in two bouts.
• They drank plain water during and after exercise for one bout and took a water solution containing electrolytes in the other.
• The participants were given an electrical stimulation on their calves to induce muscle cramp. The lower the frequency of the electrical stimulation required, the more the participant is prone to muscle cramp.

“We found that the electrical frequency required to induce cramp increased when people drank the electrolyte water, but decreased when they consumed plain water,” said Professor Nosaka.

“This indicates that muscles become more prone to cramp by drinking plain water, but more immune to muscle cramp by drinking the electrolyte water.”