A Third of Hockey Players Are Significantly Dehydrated, Researcher Finds

February 05, 2008 - News Release

About one-third of elite hockey players are significantly dehydrated while on the ice, a University of Guelph researcher has found.

Prof. Lawrence Spriet's research, which is among the first to look at the dehydration rates of hockey players, is based on a three-year study that tested the dehydration rates of players on the Canadian World Junior teams from 2005 to 2007. Spriet's work was covered by the Globe and Mail, Canadian Press, Global News Hour and CBC News at Six.

"It's thought that hockey players don't suffer from significant fluid loss through sweating as much as elite athletes in other sports do because they play in cooler temperatures," said the human health and nutritional sciences professor. "But in reality, they sweat more than some athletes because arenas aren't that cold, they wear heavy equipment and helmets, and the game requires high-intensity bursts of skating."

The study, which is to be published in Applied Physiology, Nutrition and Metabolism, was funded by the Gatorade Sports Science Institute of Canada and the Natural Sciences and Engineering Research Council of Canada and included 44 players who were tested during practices.

The pre-practice hydration status of the players was estimated through their urine, and the sweat rate was calculated based on the difference in their weight before and after practice and taking into account the amount of fluid they drank while on the ice. Sodium loss was calculated through sweat patches worn on the players' foreheads during practice as well as through their sweat rates.

Spriet found that more than 50 per cent of the players began practice mildly dehydrated and that, on average, players voluntarily replaced only 60 per cent of their sweat loss.

"But what was more alarming was that about one-third of the players lost between one and two per cent of their body mass in sweat during the practice," said Spriet who worked on the study with PhD student Matt Palmer. "That's a concern because at that level of dehydration, you are probably hurting your on-ice performance. The players think they're drinking enough, but they don't realize the magnitude of sweat loss."

Previous research suggested that losing one to two per cent of body mass through sweat can impair athletic performance, but this theory has yet to be proven in hockey players, he said.

"Sweating excessively without fluid replacement can limit performance because it decreases the plasma volume portion of the blood, which then impairs the body's ability to meet the blood flow needs of the contracting muscles. This also makes it more difficult for the body to circulate heat away from the core to the skin, where it dissipates. This causes the core temperature and heart rate to rise, leading to feelings of fatigue."

Spriet is currently conducting research to determine the level of impact dehydration has on elite hockey players' performance.

Using players from the OHL Guelph Storm team, he is measuring the on-ice performance of players when they are properly hydrated compared with when they are dehydrated. He is also measuring the effects of dehydration on the body, including core temperature and heart rate.

Prof. Lawrence Spriet
Department of Human Health and Nutritional Sciences
519-824-4120, Ext. 53745 or 905-525-9140, Ext. 22346 or cell 519-803-3624

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338, l.hunt@exec.uoguelph.ca or Deirdre Healey, Ext. 56982, d.healey@exec.uoguelph.ca.

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