Seniors with chronic diseases have a significantly higher risk of death—up to 92%—during a heat wave. A recent Canadian report examines why.

Many lab tests find that seniors are less able to detect heat than are younger adults. In turn, the body’s cooling responses, like sweating, are slower to kick in, according to the report. Similarly, seniors take longer to respond to thirst, and are more susceptible to dehydration. Obesity, diabetes and other chronic conditions that typically affect seniors have an impact as well, researchers say. Heart disease raises the risk of fatal heatstroke by 30%, while obesity increases the risk by roughly 350%, the report shows. Other factors, such as economic station and level of education, can come into play, researchers say. Poorer seniors may live in low quality housing with inadequate ventilation, which could contribute to heat deaths.  

Researchers at the University of Ottawa say research should focus more on understanding seniors’ physiological responses to high heat to determine better ways to help them cope. The review appears online in the Canadian Medical Association Journal.