Not everyone handles heat waves the same way. In the face of heat waves and climate change, humans respond in highly unequal ways.
A Complex Interaction
Thus, while some people weather heat waves without trouble, others quickly suffer from extreme fatigue or discomfort. To explain these differences, science has studied a multitude of biological mechanisms where age, physical condition, environment, and, increasingly, genetics intersect. The hypothesis of genetic influence should not be ruled out.
Indeed, according to a report by the PHG Foundation at the University of Cambridge, our genetic makeup probably plays a role in our tolerance to heat, even though its exact impact remains hard to measure. Researchers agree that our biological response to extreme temperatures results from a complex interaction between our genes and our physiological functions, though the genetic contribution remains to be explored further.
Cellular Sensory Receptors
Among the genetic avenues explored by research, the gène TRPV1 draws particular attention. This gene codes a receptor present on our sensory neurons, which activates both during a sharp rise in temperature and during the consumption of chili peppers. A 2025 study suggests that TRPV1 participates in the body’s thermal regulation, though its direct influence on our ability to withstand a heat wave has not yet been fully demonstrated.
Another promising and better-documented avenue concerns heat shock proteins, known as Heat Shock Proteins (HSP). These cellular shields are produced in large quantities by the body when body temperature rises to protect and repair cells damaged by thermal stress. Scientists are now trying to determine whether individual variations in the production of these proteins explain differences in resilience from person to person.
The Power of Acclimatization
Beyond DNA, acclimatization remains the best-proven tolerance factor by science. Indeed, after a few days of exposure to intense heat, the body actively adapts: it increases its blood volume, sweats more quickly, and retains sodium better. This self-defense mechanism explains why populations living in hot regions or accustomed to high temperatures fare much better than others.
Finally, general health and age play a decisive role in thermoregulation. Advanced age, obesity, diabetes, cardiovascular diseases, or the use of certain medications reduce the effectiveness of the body’s cooling mechanisms, increasing the risk of complications. In the end, genetics is only one piece of a large puzzle; better combining it with other factors will, in the future, help us identify vulnerable individuals more accurately and refine prevention plans.
