Repeated exposure to heatwaves, which are growing more frequent due to climate change, may accelerate ageing, particularly among manual workers, a new study warns.
Although previous research showed heatwaves had negative effects on the health of older people, it primarily focused on short-term exposure to sustained heat. The new study, published in the journal Nature Climate Change, assessed the potential long-term impact of heatwaves on health and ageing.
Researchers analysed data from 24,922 adult people in Taiwan with an average biological age of 46 years to assess how heatwaves influenced ageing.
They defined rapid ageing as the difference between biological and actual age and assessed its association with heatwave exposure.
Biological age is a measure of how well the human body functions at the molecular and organ levels compared to its chronological age based on the birthdate.
People with a greater biological age than their chronological age are at a higher risk for disease and mortality.
By analysing patient data from 2008 to 2022, the researchers found an increase in cumulative heatwave exposure was associated with a rise in age acceleration.
Though the participants appeared to adapt to heatwave conditions over the 15-year period, the harmful health effects did not disappear.
Manual workers, rural residents and people in communities with fewer air conditioning units were more susceptible to the impacts of heatwaves on ageing, the study found.
The findings suggest people living in places that experience more days of high heat show greater biological ageing on average than those in cooler regions.
“Here we analysed data from 24,922 adults in a longitudinal cohort in Taiwan and used linear mixed models to show heatwaves accelerate ageing,” the researchers said.
The new study calls for policies to reduce environmental inequalities and improve heatwave resilience, especially among vulnerable groups. It also underscores the need for targeted protection and efficient healthcare resource allocation.
The researchers call for more studies involving more diverse groups and assessing other important factors like time spent outdoors, household environment, and usage habits of air conditioners. They caution that a combination of hot conditions like during heatwaves and high humidity poses a particular risk for older adults as human beings gradually lose the ability to regulate their body temperature through sweating.
