Soaring temperatures eased Wednesday in parts of British Columbia, Yukon and Northwest Territories, but were expected to remain in high in eastern British Columbia and the Prairies for several days. Parts of New Brunswick and Nova Scotia were also under heat warnings Wednesday.
People used to high heat in Arizona, for example, can withstand temperatures similar to what British Columbia is experiencing, but extreme heat is more abrupt for those living in usually mild climates. A heat wave in June in certain areas can also be more striking than one in August, after months of acclimatizing to higher temperatures.
High overnight temperatures that don't allow a reprieve while the sun is down can make things worse, Schwandt added, saying heatstroke "does accumulate over time." Social vulnerabilities, including living in an apartment without air conditioning, also impacts who might fall ill to a heat-related condition.
"When you get heatstroke it actually starts to impact our basic function, so it can mimic signs of a stroke -- slurred speech, seizures, imbalanced or irregular walking," Gaco said. "It can also affect how we generate energy in the body ... and that can cause muscle breakdown and liver or kidney injury."
While blood vessel dilation helps cool the body, Jacobs said it can be problematic for people who are active outside in high-temperature conditions, where the heart has to work harder to supply blood to muscles. Gordon McBean, a climatologist with Western University, said B.C.'s heat wave feels more excessive because of the presence of a "heat dome" -- hot air that isn't circulating around it. While the heat wave is moving east, temperatures in other provinces aren't expected to reach the record-highs seen in British Columbia because weather patterns evolve as they shift.