Heatwaves make you age faster, new research warns

Repeated exposure to heatwaves is accelerating biological aging in humans, according to a new study. The research, published in Nature Climate Change, indicates that the impact of heatwaves on aging is comparable to the effects of smoking, alcohol consumption, poor diet, or lack of exercise.

The study analysed data from nearly 25,000 adults in Taiwan over a 15-year period, examining the relationship between heatwave exposure and biological age — a measure of overall health determined through medical tests assessing blood pressure, inflammation, cholesterol, and organ function.

The findings revealed that individuals who experienced four additional heatwave days over a two-year period had a biological age increase of approximately nine days. Manual workers, who typically spend more time outdoors, were particularly affected, with their biological age increasing by 33 days during the same period.

Significant cumulative effect

While these increases may seem modest over two years, the researchers caution that the cumulative effects over several decades could be significant.

Dr Cui Guo, lead author of the study from the University of Hong Kong, emphasised that the health impacts could be much greater in the future, as heatwaves become more frequent and prolonged due to climate change. “If heatwave exposure accumulates for several decades, the health impact will be much greater than we have reported,” Dr Guo stated.

• How heatwaves affect the body

• Beyond accelerating biological aging, extreme heat stresses nearly every system in the body:

• Cardiovascular strain – Heat forces the heart to pump harder to keep the body cool, raising risks of heart attacks and strokes.

• Kidney stress – Dehydration from heat increases the risk of kidney stones and long-term kidney disease.

• Respiratory problems – Hot weather worsens air quality and can trigger asthma or chronic obstructive pulmonary disease (COPD).

• Neurological effects – Heat can cause confusion, dizziness, fainting, and in severe cases, heat stroke, which can be fatal.

• Mental health impacts – Studies link prolonged heat to increased anxiety, aggression, and higher rates of hospital visits for psychiatric conditions.

• Pregnancy risks – Heat exposure has been tied to higher risks of premature birth and low birth weight.

• Workplace injuries – Hot conditions increase fatigue and slow reaction times, raising the likelihood of accidents, especially in outdoor or manual labor jobs.

The study also highlighted that the total impact on global populations would be substantial, as everyone is affected during heatwaves. Higher biological age is a strong predictor of increased risk of death, making the long-term effects of heat exposure a significant public health concern.

'Paradigm shift'

Professor Paul Beggs from Macquarie University in Sydney, Australia, who was not involved in the research, described the findings as a “paradigm shift” in understanding the extent and severity of heat’s impact on health, the Guardian reported.

He noted that while many individuals may have experienced heatwaves without immediate harm, this research shows that exposure to heatwaves affects the rate at which we age.

The study’s results are particularly concerning in light of the ongoing climate crisis. Fossil fuel burning, the main driver of climate change, reached record levels in 2024, contributing to more frequent and intense heatwaves worldwide.

Health impact

These environmental changes are expected to exacerbate the health impacts on populations, especially among vulnerable groups such as manual workers and those with limited access to air conditioning.

The research underscores the urgent need for public health strategies to mitigate the effects of heatwaves. This includes improving access to cooling resources, enhancing public awareness about the health risks of heat exposure, and implementing policies to address the underlying causes of climate change.

As the global population ages and climate change accelerates, protecting individuals from the long-term health impacts of heatwaves is becoming increasingly critical.