Every athlete has dealt with the pesky condition—muscle cramps impact affects about 39% of marathon runners, 52% of rugby players and 60% of cyclists.
The causes of muscle cramps are likely to be multifactorial, but dehydration and electrolytes deficits are considered key factors. With that in mind, researchers from Edith Cowan University (ECU) tested the hypothesis that post-exercise muscle cramp susceptibility would be increased with spring water ingestion, but reduced with oral rehydration solution ingestion during exercise.
The study was published in the Journal of the International Society of Sports Nutrition.
The study involved 10 men who ran on a downhill treadmill in a hot, 95ºF room for 40 to 60 minutes to lose 1.5-2% of their body weight through sweat in two conditions.
The participants drank plain water during and after exercise for one condition and took a water solution containing electrolytes in the other condition.
The men 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.
The researchers found that drinking electrolytes instead of pure water can help prevent muscle cramps.
"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 lead researcher Professor Ken Nosaka, from ECU's School of Medical and Health Sciences. "This indicates that muscles become more prone to cramp by drinking plain water, but more immune to muscle cramp by drinking the electrolyte water."
Nosaka, who began researching muscle cramps after his own bout with cramps during tennis, said the study builds on the evidence that a lack of electrolytes contributes to muscle cramps—not dehydration.
Oral rehydration solutions
Oral rehydration solutions, commonly found in pharmacies, contain electrolytes in specific proportions and can be made with water, salt and sugar. The solution returns the amount of fluids, sugars and electrolytes in the body back to normal levels.
Professor Nosaka said electrolytes have many benefits for both athletes and the general population.
"Electrolytes are vital to good health—they help the body to absorb water more effectively than plain water and replace essential minerals lost through sweat or illness," he said. "People should consider drinking oral rehydration fluids instead of plain water during moderate to intense exercise, when it's very hot or when you are sick from diarrhoea or vomiting."
“It should be further investigated as to what and how much electrolytes should be contained in the beverage, and whether commercially available sport drinks that contain some electrolytes are as effective as OS-1 [oral rehydration solution] in reducing muscle cramp susceptibility,” the researchers concluded.
In addition to further research to find out the optimal amount of electrolytes to prevent muscle cramps, Nosaka is planning to investigate how electrolytes could help the elderly and pregnant women.
Source: Journal of the International Society of Sports Nutrition
2021; 18 (1) DOI: 10.1186/s12970-021-00414-8
“Effect of oral rehydration solution versus spring water intake during exercise in the heat on muscle cramp susceptibility of young men”
Authors: W. Lau et al.