Heat exhaustion is more common in Olympic athletes who use nicotine, says Brock expert – The Brock News

Olympic athletes with a nicotine addiction, watch out!

A new study led by Brock has found that consuming nicotine – whether by smoking, chewing, vaping or even wearing a patch – increases the risk of heat exhaustion during intense exercise, especially in a hot environment.

The latest study by Brock University kinesiology professor Toby Mündel, conducted alongside an international research team, comes just days before the opening ceremony of the 2024 Summer Olympics in Paris. The findings are particularly relevant because Mündel’s previous research has shown high levels of nicotine use among elite athletes.

“In addition, climate change has increased summer temperatures in the Northern Hemisphere,” says Mündel, Canada’s research director for extreme human environmental conditions.

He says the last Summer Olympics in Tokyo, Japan, were “the hottest and wettest Olympics ever,” and the upcoming Games in Paris could potentially break those records again, according to forecasts.

Holding the Olympic Games in an urban environment with little green space and lots of asphalt and concrete – which absorbs heat – increases the risk of heat stroke for athletes and spectators, he says.

Toby Mündel, Professor of Kinesiology at Brock University and Canada Research Chair in Extreme Human Environments.

Mündel and his team wanted to find out whether nicotine increases body temperature – measured by the temperature of the gastrointestinal tract – mainly by increasing metabolism or by reducing blood flow to the skin.

Mündel based his argument on studies that showed that former smokers tend to gain weight when they quit smoking. According to Mündel, they concluded that “nicotine seems to speed up a person’s metabolism, essentially increasing the number of calories burned.”

Other studies have also found that nicotine constricts blood vessels, reducing blood flow to the skin. Blood flow to the skin allows the body to release heat and provides the fluid for sweat. When this is restricted, the body can overheat, he says.

Ten male study participants who had never used nicotine wore a nicotine patch overnight and then repeated this with a placebo patch. Neither the participants nor the researchers knew when they received active and inactive patches.

The next day, the participants cycled for an hour at 20 °C and then again at 30 °C. After each trial, the researchers measured the participants’ gastrointestinal and skin temperatures. The experiment was repeated four times.

Two participants had to leave the nicotine trials at 30 °C because one had reached the ethically maximum permissible limit for gastrointestinal temperature and the other discontinued due to “nausea and chills”.

Through various measurements of blood flow to the skin and gastrointestinal tract, the team concluded that nicotine consumption increases heat stress and thereby leads to heat exhaustion by reducing blood flow to the skin.

According to Mündel, the study’s findings are relevant not only for athletes, but also for other people who work in high-temperature environments, including the military, firefighters and some industries.

The team’s findings are described in their article “Nicotine exacerbates heat stress in trained men: A randomized, placebo-controlled, double-blind trial,” which was published online on July 4 in the Journal of Applied Physiology.

The study is funded by the Natural Sciences and Engineering Research Council of Canada of the Canadian federal government, the Canadian government-funded Canada Research Chairs program and a grant from the World Anti-Doping Agency.

Mündel says he is sometimes asked whether nicotine use should be partially or completely banned among athletes. He points out that nicotine stays in the body for a while, so a ban in the hours or days before a competition may not be effective.

It is crucial that athletes and spectators drink plenty of water and maintain a high hydration level, he says.