Heatwaves Are Harming the Young More Than the Elderly: Study Finds

Many recent studies assume that elderly people are at particular risk of dying from extreme heat as the planet warms. A new study of mortality in Mexico turns this assumption on its head: it shows that 75% of heat-related deaths occur among people under 35 -- a large percentage of them ages 18 to 35, or the very group that one might expect to be most resistant to heat.

The analysis found that from 1998 to 2019, the country suffered about 3,300 heat-related deaths per year. Of these, nearly a third occurred in people ages 18 to 35 -- a figure far out of proportion with the numbers in that age bracket. Also highly vulnerable: children under 5, especially infants. Surprisingly, people 50 to 70 suffered the least amount of heat-related mortality.

The researchers say several factors may be at work. Young adults are more likely to be engaged in outdoor labor including farming and construction, and thus more exposed to dehydration and heat stroke. The same goes for indoor manufacturing in spaces that lack air conditioning. Young adults are also more likely to participate in strenuous outdoor sports; the researchers point out.

Wet bulb temperatures are often converted by popular media into "real-feel" heat indexes on the Fahrenheit scale, where numbers can vary depending on the exact combination of heat and humidity. According to the study, wet-bulb temperatures of around 13 C are ideal for young people; in this range, they suffer minimum mortality. This study found that the largest number of deaths occurred at wet-bulb temperatures of just 23 or 24 C, in part because those temperatures occurred far more frequently than higher ones, and thus cumulatively exposed more people to dangerous conditions.

Using the same daily temperature and mortality data, the researchers found that elderly people died predominantly not from heat, but rather modest cold. Among other things, older people tend to have lower core temperatures, making them more sensitive to cold. In response, they may be prone to staying indoors, where infectious diseases spread more easily.

Reference: https://news.climate.columbia.edu/2024/12/06/high-heat-is-preferentially-killing-the-young-not-the-old-new-research-finds/