Patient support charity Kidney Care UK has also urged people to stay hydrated as the chances of suffering acute kidney injury (AKI) are more likely in hot weather.
AKI is a sudden drop in kidney function and can range from a small loss of function to complete kidney failure.
The charity said the risk increased alongside higher temperatures, particularly above 25C.
During a seven-day heatwave in July 2021, AKI diagnoses increased by 29%, the charity said.
It added that those most at risk of developing AKI are people with diabetes, high blood pressure, chronic kidney disease, heart failure and those over 65 years, although it can happen to anyone, especially if they are dehydrated.
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