Dangers of vaping in hot weather

A new study shows that vaping can increase the risk of deadly heat exhaustion as summer temperatures rise.

An international team of researchers recruited 10 men who smoked e-cigarettes and gave them a nicotine patch to wear overnight.

The next day, they were all asked to exercise on an ergometer for 60 minutes without stopping, in rooms with temperatures between 20 and 30 degrees Celsius.

The research team then measured the volunteers' internal temperatures, using a temperature-testing "pill" that was swallowed and then transmitted the data wirelessly to an app.

The day after the experiment, they were given a placebo patch without nicotine and repeated the entire exercise. Two participants had to leave the nicotine patch experiments in the 30°C rooms, one because he "reached his maximum gastrointestinal temperature", and the other stopped because of "nausea and chills."

The researchers concluded that nicotine use increases "heat stress" during muscular exertion, leading to heat exhaustion, by reducing blood flow to the skin.

Nicotine speeds up a person's metabolic rate, essentially increasing the number of calories they burn, said study leader Toby Mundell, a physiologist at Brock University in Canada. 

Other studies have found that nicotine constricts blood vessels, so less blood flows to the skin. This flow is necessary for the body to release heat and sweat, so restricting it can raise body temperature.

The findings linking nicotine to heat exhaustion also raise concerns about the upcoming Olympic Games, set to begin in Paris next week , Mundel said , especially since he found that from urine tests collected during international sporting events between 2012 and 2020, 55% of baseball players, 43% of hockey players and 42% of soccer players were nicotine users, according to elevated levels in their samples.

Mundel said the findings of his study are relevant not only to athletes, but also to people who work in high-temperature environments, including firefighters.