Features
More Water With Your Ice?
CBS prof's research among first to look at dehydration rates in elite hockey players
BY DEIRDRE HEALEY
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| Prof. Lawrence Spriet is working with members of the Guelph Storm to test the impact of dehydration on their on-ice performance. Photo by Grant Martin |
Prof. Lawrence Spriet, Human Health and Nutritional Sciences, has to strap on his ice skates to do his current research. He's testing how dehydration affects the performance of elite hockey players — and what better way to do that than on the ice?
Using players from the OHL Guelph Storm team, Spriet is measuring the on-ice performance of players when they're properly hydrated compared with when they're dehydrated. He's also measuring the effects of dehydration on the body, including core temperature and heart rate. He's doing the testing at the Sleeman Centre in downtown Guelph before and after practices.
Spriet's research, which is among the first to look at the dehydration rates of hockey players, has recently captured media attention, with a number of national newspapers and TV news stations coming out to the rink to catch his field study in action.
The current testing is a followup to previous research that found about one-third of elite hockey players are significantly dehydrated while on the ice. Those findings are based on a three-year study that tested the dehydration rates of players on the Canadian World Junior teams from 2005 to 2007.
“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,” says Spriet, who worked on the study with PhD student Matt Palmer. “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. It 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. That's a concern because at that level of dehydration, you're probably hurting your on-ice performance. The players think they are 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 says.
“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 has conducted similar dehydration testing on the NHL New York Rangers and the Toronto Raptors, then helped players adjust their liquid intake to ensure they're getting enough fluids.
“Being properly hydrated is just one more thing elite athletes can have in their arsenal.”