Study debunks water myth
Stephen Cheung had no preconceived notions when he began researching his latest project.
The 46-year-old professor at Brock University wasn’t quite sure what he and his research team would come up with when they went to work on the belief that dehydration curbs the strength of athletes in hot conditions.
“You always go in with an idea of what might happen, but at the same time, you are still surprised at the end at just how little impact that dehydration had on you,” Cheung said. “I’m a competitive cyclist and I hear the message of hydrate, hydrate, hydrate.”
Cheung went into the study without any particular bias and was surprised with the results.
“We just wanted to be good scientists and objectively test this idea.”
The research has debunked the widely held belief that dehydration saps the strength of athletes performing in hot conditions.
It is common to see distance runners or cyclists gulp water and other drinks during long races, trying to replenish fluids and avoid the loss of strength that has long been accepted as a consequence of dehydration.
But the Brock study, published this month in the Scandinavian Journal of Medicine and Science in Sports, concludes there is no such impairment.
Cheung started planning for the tests in late 2012 and early 2013. Most of the experiments were done in the summer of 2013 through the fall.
His team then spent last year analyzing the data before submitting it for publication and revising it.
“I’ve been studying hydration for a number of years. It was one of the topics of my PHD back in the mid ‘90s,” said Cheung, a Hong Kong native who grew up in Vancouver and moved to Brock eight years ago. “I wanted to look at the importance of hydration.
“We’ve been bombarded with the message that you need to hydrate, but yet, still you look at elite marathoners and they barely touch water at all during even competitions in the heat. Previous studies consisted of subjects getting hydrated one day and not the next. These studies manipulated the physical state of hydration as well as the perception and physiology.
“All existing studies manipulate hydration by giving or not giving water, so that manipulates both the physical state of hydration and also the perception of drinking and thirst. In other words, ‘I’m thirsty or upset that I don’t get to drink, so I’m not going to ride as hard,’ ” Cheung said.
His study involved 11 trained racing cyclists who wore IV drips while riding stationary bikes under competition-like conditions. Some cyclists had IV drips containing a saline solution to replenish fluids lost through sweat, but others had IV drips that were shams, providing no rehydration at all.
The cyclists were not told which type of IV drip they were wearing, and the researchers found there was virtually no difference in their performances.
“We’re the first study to separate the conscious awareness of hydration status to truly test that by itself,” said Cheung. “This includes all the studies used to develop current hydration guidelines.
Cheung wanted it made clear that despite his findings, he’s not anti-water.
“The message I want t o impart is that you can drink, but whether you do or not, is not really going to impact your performance, especially if you use it as a physiological crutch that I have to drink,” he said. “I’m not advocating or suggesting that on a day-to-day basis you don’t need to be drinking or you shouldn’t drink.”
Water is important for recovery and proper nutrition and is human’s most vital nutrient.
“If we don’t drink we’re dead in seven to 10 days,” Cheung said. “At the same time, for a one-off competition, you don’t need to stress about hydration.”
Cheung understands some will question his findings.
“There is that traditional backlash that will come but there are athletes and sports scientists out there who understand what we are talking about and they appreciate the science involved,” he said.
Cheung was assisted by Brock graduate students Greg McGarr, Matt Mallette, Cody Watson, Phil Wallace and Isabel Kim. Dr. Matt Greenway from McMaster University co-authored the report.