The Accelerating Effect of Extreme Heat on Human Biological Aging

It is a well - established fact that heat, through dehydration, can lead to physical exhaustion. However, the connection between heat and aging is a topic that has gained significant attention recently.

A recent study, published in the journal Nature Climate Change, has concluded that extreme heat accelerates the biological aging of the human body. This finding is particularly concerning given the escalating frequency of heatwaves, a consequence of climate change.

The researchers in this study were not focused on the impact of solar radiation on the skin. Instead, their concern was biological aging. Biological age differs from chronological age (the age one states when asked how old they are). Biological age reflects the functional status of cells, tissues, and organs within the body. It can be determined by assessing physiological and molecular markers, along with the use of various tests. Examples of such tests include measuring lung function, cognitive ability, or bone density.

The research, which analyzed the long - term medical data of 24,922 individuals in Taiwan collected between 2008 and 2022, found that over time, exposure to extreme heat can undermine bodily systems. This was evident in tests related to blood pressure, cholesterol, and blood function. In the long run, this exposure can heighten the risks of cardiovascular disease, cancer, diabetes, and dementia. The study also revealed that the aging effect of extreme heat was on par with other harmful behaviors like smoking or alcohol consumption.

During the study period, Taiwan experienced approximately 30 heatwaves, defined by the research team as periods of sustained high temperature over several days. First, the researchers calculated the biological age of each individual based on the results of multiple medical tests, such as those for liver, lung, and kidney function. They then compared the biological age with the chronological age to determine the relative speed at which an individual's biological clock was ticking. This information was cross - referenced with the individuals' likely exposure to heatwaves.

The results indicated a clear relationship: the more extreme heat events an individual experienced, the faster their biological age advanced relative to their chronological age. On average, within the studied cohort, exposure to heatwaves equivalent to two years added between eight and 12 days to a person's biological age.

Cui Guo, an environmental epidemiologist at the University of Hong Kong and the lead author of the study, stated in a Nature press release, "Although the numerical increase may seem minor, over time and across different populations, this effect could have substantial implications for public health."

The study also identified that individuals engaged in physical labor and those living in rural areas were more prone to accelerated biological aging, likely due to increased exposure to heatwaves. However, an unexpected positive trend was observed: over the 15 - year period of analysis, the impact of heat exposure on biological aging actually decreased. While the exact cause remains unknown, Guo suggests that the growing prevalence of cooling technologies, such as air - conditioning, may be a contributing factor.

This article was originally published on WIRED en Español and has been translated from Spanish.