Many areas are currently experiencing an intense heatwave, with temperatures in some places reaching nearly 40°C (104°F).
As a result, both the Met Office and the UK Health Security Agency have issued red heat warnings, according to Express.
Several schools have also been closed due to the extreme weather.
Authorities are urging people to stay in the shade, drink plenty of water, and avoid strenuous physical activity during the hottest hours of the day.
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The body has to work harder
When temperatures become very high, the body tries to cool itself by directing more blood to the skin.
This helps the body release excess heat.
According to BBC journalist and former weather presenter Lara Lewington, this also means the heart has to work harder.
That can place significant strain on the body, particularly on older adults and people with underlying health conditions, Express reports.
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The leading cause of death
Many people believe that heatstroke or dehydration is the greatest danger during a heatwave, but that is not the case.
According to Lara Lewington, heart failure is the most common cause of death during periods of extreme heat.
The additional strain on the heart can increase the risk of heart failure, blood clots, and stroke, particularly among vulnerable individuals.
She therefore recommends staying cool, drinking enough fluids, and paying special attention to older adults and other people who are especially at risk.
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