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If the sweltering nights and sweaty commutes weren't bad enough, Britain's scorching summer could also be speeding up how fast your body ages, according to a new study.

Researchers have discovered that intense, prolonged heatwaves appear to push the body's internal clock forward by up to half a year.

People with higher BMIs and those living in cities are most affected, the findings revealed.

And it could be because heat triggers a range of internal disruptions, putting our cells under increased stress and throwing the body's metabolism off balance.

'As global warming intensifies, heatwaves are becoming increasingly frequent, prolonged and severe, thereby amplifying their associated health burdens,' the team wrote in the journal Cyborg and Bionic Systems.

'We found that heatwave exposure was associated with accelerated biological ageing among middle–aged and older adults.'

They added that it 'highlights the vulnerability of ageing populations to climate–related thermal stress'.

The findings have been published amid a slew of heatwaves in the UK. The June heatwave was particularly exceptional, with temperatures soaring to 38°C in Lingwood as England recorded its hottest June on record.

The study showed that each heatwave (HW) was linked with an increase in biological age. Intense, prolonged periods of heat appeared to push the body's internal clock forward by as much as half a year

The findings have been published amid a slew of heatwaves in the UK. Pictured: A woman uses a fan to shelter from the sun in London

For the study, the team, from Zhejiang University, analysed data from more than 2,300 adults across China. Measurements of their biological age were taken in both 2011 and 2015.

Their heatwave exposure was measured using weather data from the 12 months before each biological assessment.

In the study, a heatwave was defined as at least four consecutive days where temperatures exceeded the hottest 2.5 per cent of days typical for that city.

Analysis revealed each additional heatwave was linked to a 0.531–year increase in biological age. People who experienced more intense heatwaves appeared to age at a quicker pace than those who experienced milder heat.

Further investigations revealed extreme heat appears to put the body under a form of prolonged physiological stress.

When temperatures soar, the body has to work harder to maintain its normal internal conditions, placing extra strain on processes that control how cells produce energy and use fats and sugars.

The researchers found signs that this may disrupt the body's metabolism, with repeated heatwave exposure linked to higher levels of cholesterol and HbA1c – a measure of average blood sugar levels.

This matters because keeping blood fats and blood sugar under control is an important part of maintaining healthy cells and organs as we get older.

Repeated heatwave exposure was linked to higher levels of cholesterol and HbA1c – a measure of average blood sugar levels

Britain has already endured four distinct heatwaves since late spring, making 2026 an unusually hot year. Pictured: Parched fields at Newlands Corner, near Guildford

The team also found evidence in older mice that heatwave exposure altered genes involved in lipid metabolism and insulin resistance – processes that help the body handle fats and regulate blood sugar.

Heat can also trigger oxidative stress, mitochondrial dysfunction and strain within the cell's protein–making machinery, according to the researchers.

Mitochondria are essentially the tiny power stations inside cells, so disrupting their function could make it harder for cells to maintain their normal operations.

Meanwhile, problems with the systems responsible for making and folding proteins could make it more difficult for cells to repair and maintain themselves.

Over time, these kinds of metabolic and cellular stresses could contribute to the gradual loss of physiological resilience that occurs with ageing.

The researchers therefore suggest that repeated heatwaves may act as an additional environmental stressor, potentially nudging the body's biological ageing process forward.

'These results suggest that recurrent heatwave exposure may contribute to accelerated biological ageing, potentially through metabolic disruption,' they concluded.

They added that heatwaves may 'influence ageing trajectories through long–term physiological damage'.

Britain has already endured four distinct heatwaves since late spring, making 2026 an unusually hot year.

The first struck in late May, followed by another in June, a third in early July and one last week, according to the Met Office.

The Met Office also noted that 2026 has been exceptional for heat, with 35°C or higher recorded in May, June and July for the first time in UK weather records.

England and Wales have also recorded their driest July in 190 years, with some places experiencing no rainfall for more than 45 days.