Heat Waves Could Speed Up Aging
Long-term exposure to extreme heat can nudge bodies to age faster than their actual years.
Every summer, heat waves affect millions of people around the world. The World Meteorological Organization reported that at least 10 countries experienced temperatures higher than 50ºC in 2023–2024. With the increasing frequency, duration, and magnitude of heat waves comes the elevated burden of non-communicable diseases. Exposure to high temperatures can exacerbate illnesses like cardiovascular disease, diabetes, mental health, and asthma, leading to higher mortality and disability rates.1
Most studies have focused on the health consequences of short-term exposure to heat waves. Now, researchers found that individuals who lived through heat waves over an extended period showed signs of accelerated aging.2 Coupled with a previous report that highlighted the negative impact of prolonged high temperatures on brain development in children, these findings call attention to the long-term consequences of heat waves on the body.3 The team published their results in Nature Climate Change.
Several of the co-morbidities associated with heat exposure are also linked to aging—a process of physiological changes at the tissue, cellular, and molecular level. The differences in the rates of these changes can create discrepancy between a person’s actual chronological age and biological age. Understanding the relationship between heat waves and aging could help researchers and clinicians decipher the mechanism by which high temperatures worsen age-related conditions.
To do so, Cui Guoan environmental epidemiologist at the University of Hong Kong, and her colleagues analyzed data from more than 24,000 adults in Taiwan, over a period of 15 years (2008–2022). They obtained results of various medical tests, such as inflammation, cholesterol, diverse organ functions, and blood pressure, among others, to calculate each individual’s biological age. They compared this to the adults’ chronological age to obtain their biological age acceleration. The team also acquired a history of heat wave exposures in the two years before a person’s medical screening visit, which included measures such as sum of temperatures across all heat wave days, total number of heat wave events, and duration of each spell.
Guo and her colleagues observed that people who experienced higher cumulative temperatures also displayed a corresponding increase in biological age acceleration. With each interquartile range increase in the cumulative heat exposure, aging accelerated by 0.023–0.031 years. The team noticed the heat waves affected manual workers, rural residents, and individuals from areas with fewer air conditioners more adversely.
While the mechanisms by which heat waves hasten aging remain to be fully understood, the researchers hinted at potential pathways based on previous studies. They speculated that elevated temperatures could reduce telomere lengths, disrupt redox homeostasis, cause DNA damage, and lead to mitochondrial fragmentation, all of which are strong contributors to cellular senescence.4–6 Further studies could help identify which of these are pertinent to heat-driven accelerated aging.