As a dangerous heat wave grips much of Ontario and Quebec, with alerts extending east to the Maritime provinces, a University of California professor warns that using fans in sweltering conditions may actually harm rather than help.
Fans Can Raise Body Temperature
Stefano Schiavon, a professor at the University of California, explained that in extreme heat, fans can increase body temperature by blowing hot air onto the skin rather than providing cooling relief. “It actually harms you,” Schiavon said, emphasizing that fans are only effective when the air temperature is lower than body temperature.
According to Schiavon, when ambient temperatures exceed 35°C (95°F), fans can accelerate heat gain through convection and dehydration. This contradicts common belief that fans always cool the body. The warning comes as heat warnings remain in effect across Canada, with temperatures soaring above 30°C in many regions.
Heat Wave Impacts Across Canada
The heat wave is affecting millions, with severe thunderstorm watches also in effect in some areas. In Ottawa, thunderstorms grounded Prime Minister Mark Carney’s plane, canceling a planned trip to Alberta. Canada Day celebrations proceeded under extreme heat, with events in Calgary, Winnipeg, and Regina drawing large crowds despite the weather.
In Ontario, the city of London is enforcing fireworks bylaws, while Windsor police charged a teen after a hit-and-run. The heat has also contributed to power outages in the northeast, affecting hundreds of residents.
Expert Advice on Cooling
Schiavon recommends alternatives such as air conditioning, cool showers, or damp cloths. He advises against relying on fans when the heat index exceeds 37°C (99°F). Public health officials echo this, urging people to stay hydrated and avoid strenuous activity during peak heat hours.
The warning is particularly relevant for vulnerable populations, including older adults and those with chronic conditions. In Guelph, a brewery closed temporarily due to a fire, but heat-related incidents continue to rise. A seven-year-old child remains missing in a Hamilton conservation area, and a kayaker died in a separate incident.
