TUESDAY, Oct. 13, 2015 (HealthDay News) -- The grueling mixed martial arts known as "cage fighting" may harm participants in ways spectators may not even realize, a new study suggests.

Researchers in Britain say their study of U.K. cage fighters found that many are resorting to drastic methods to quickly lose weight before a fight.

These practices "are dangerous to health, may contribute to death, and are largely unsupervised" in cage fighting, warned the researchers, led by Dr. James Morton, a sports and exercise scientist at Liverpool John Moores University.

Advertisement

As Morton's team explained, cage fighting has 11 different weight classes. And fighters often try to compete at the lowest possible weight by using chronic dehydration methods such as saunas, sweat suits, hot baths and pills that boost fluid loss (diuretics).

Two years ago, Brazilian cage fighter Leandro Souza died in a sauna after he tried to lose 20 percent of his body weight -- 33 pounds -- in seven days. And there have been several recent cases of fighters who had to withdraw from competition or retire due to problems caused by repeated rapid weight-loss methods, the researchers said.

In the study, Morton and his colleagues surveyed 30 U.K. cage fighters in five weight classes, and came up with what they called "alarming" results.

About two-thirds of the fighters used a weight-loss practice called "water loading," where fighters reduce their salt intake and boost their water consumption to about 6 gallons over three days.

Seventeen percent of the fighters used commercial products to increase their sweating -- either by stimulating circulation or blocking pores. Also, 37 percent took prescription and/or over-the-counter diuretics, and 13 percent used intravenous lines and glycerol to rehydrate after a weigh-in. Weigh-ins typically occur 24 to 36 hours before a fight, Morton's team said.

The researchers also found that nearly three-quarters of fighters used nutritional supplements while losing weight, but 60 percent did not know if these had been tested for banned substances. All of the fighters either fasted completely or ate a low-carbohydrate diet in the three to five days before the weigh-in -- putting them at risk for energy depletion, the researchers said.

Only 20 percent of the fighters sought dietary advice from a qualified sports dietitian or nutritionist. Instead, most got dietary advice from coaches, other fighters or the Internet, according to the study published Oct. 13 in the British Journal of Sports Medicine.

In addition to other health dangers, rapid and extreme dehydration also boosts the risk that blows to the head during a fight will cause brain damage, the researchers said.

They made a number of recommendations, including adding more weight classes, shortening the time between weigh-in and competition, and offering fighters more education on how to lose weight safely.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases explains how to select a safe and successful weight-loss program.