Heatwaves are making people age faster, fresh study warns

Repeated exposure to heatwaves, which are growing more frequent due to climate change, may accelerate ageing, 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. It particularly affects manual workers.

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.

On the other hand, beyond the physical discomfort of being overheated and drained, these intense periods of heat are increasingly taking a toll on our mental well-being and mood.

So, how exactly does this intense heat affect our mood and our mental wellbeing? We spoke with Dr Ravi Gill, practitioner psychologist, to uncover the psychological impact of prolonged high temperatures and what we can do to stay balanced.

Can heatwaves impact our mood? Physiological changes in the body and brain due to heat can significantly affect mood during a heatwave. “Heat disrupts neurotransmitter systems (serotonin), impairs sleep and raises stress hormones like cortisol, which are key regulators of mood and impulse control,” says Gill.

The physical discomfort and disrupted sleep from heatwaves can also exacerbate mood instability, trigger anxiety spikes, or worsen irritability, says the psychologist.

“Lingering discomfort and environmental stress strains emotional resilience, making even minor irritants feel overwhelming,” adds Gill. “Heatwaves can also escalate social tensions – whether at home, in traffic, or public spaces – turning minor triggers into conflicts.” Research also suggests that people with pre-existing mental health conditions are more vulnerable during heatwaves.

What impact do sleep disturbances by heat have on our mood and minds? “High nighttime temperatures make it harder for the body to drop its core temperature, which is essential for initiating and maintaining deep, restorative sleep,” says Gill. “People wake more often, particularly during REM sleep, which is vital for emotional processing and memory consolidation. Difficulty falling asleep and staying asleep reduces overall rest.” This can have a profound impact on our emotional regulation.

“Poor sleep lowers activity in the prefrontal cortex (responsible for impulse control) and heightens amygdala reactivity (linked to fear, anger, and anxiety). This makes us more emotionally volatile,” explains Gill. “Lack of REM sleep amplifies stress responses and reduces resilience to everyday frustrations.

What impact can heatwaves have on our cognitive functions like memory, focus and decision-making? “Heatwaves can impact and impair core cognitive functions like memory, focus and decision-making, and the reasons are a mix of direct brain effects and secondary factors like dehydration and sleep disruption,” says Gill.

The Independent