What if everything we thought we knew about who’s most at risk during extreme heat was wrong? A shocking new study turns conventional wisdom on its head, revealing that in Mexico, it’s actually young people – not the elderly – who are dying more frequently from heat exposure.
The research shows that 75% of heat-related deaths occur among people under 35 years old, with many victims being otherwise healthy young adults. “It’s a surprise. These are physiologically the most robust people in the population,” says study coauthor Jeffrey Shrader of Columbia University’s Climate School. “I would love to know why this is so.”
For decades, scientists and public health officials have focused their heat-protection efforts on elderly populations, believing them to be most vulnerable to temperature extremes. However, the study’s analysis of death records in Mexico revealed something unexpected: between 1998 and 2019, the country experienced about 3,300 heat-related deaths each year, with nearly a third occurring in people ages 18 to 35. Even more surprising, people aged 50 to 70 – who were thought to be highly vulnerable – actually had the lowest rates of heat-related deaths.
The researchers focused on something called “wet-bulb temperature,” a measurement that combines heat and humidity to show how well our bodies can cool themselves through sweating. They found that people under 35 may be most likely to die from heat, particularly due to their work conditions. “These are the more junior people, low on the totem pole, who probably do the lion’s share of hard work, with inflexible work arrangements,” explained Shrader. Young adults typically fill jobs in construction, farming, and factory work – occupations that often involve intense physical activity in hot environments with little flexibility to take breaks or avoid the hottest parts of the day.
The study’s findings have significant implications, as global temperatures continue to rise. “We project, as the climate warms, heat-related deaths are going to go up, and the young will suffer the most,” said the study’s co-lead author, R. Daniel Bressler, a PhD candidate in Columbia’s Sustainable Development program. The high death rate among young adults stems largely from their work conditions, which often involve intense physical activity in hot environments with limited flexibility to take breaks or avoid the hottest parts of the day.
The research is relevant to other countries with large young populations and hot climates, such as many in Africa and Asia. The findings also raise important questions about how we value temperature-related deaths in policy decisions and the need for age-specific climate adaptation strategies. As Shrader noted, “I would love to know why this is so.”