The NHS is urging people to think carefully about what they drink as Britain faces its hottest day of the week, with temperatures forecast to climb as high as 37C and even 38C in some areas. An amber extreme heat warning has been issued by the Met Office for parts of England, warning that the scorching conditions could have serious impacts on health, travel and infrastructure.
NHS advice on drinks during extreme heat
While many people automatically reach for a cup of tea or coffee, the NHS advises avoiding both during periods of extreme heat because they contain caffeine. The NHS says: "Cool yourself down. Have cold food and regular cold drinks. Drink extra fluids but avoid alcohol, caffeine and hot drinks, and have a cool shower or put cool water on your skin or clothes."
Caffeine acts as a mild diuretic, meaning it can increase how much water your body loses through urination. During a heatwave, when your body is already losing fluids through sweating, this can make it harder to stay properly hydrated and increase the risk of dehydration.
Why hot drinks can be counterproductive
Hot drinks can also make you feel even warmer. Although they can trigger sweating, which may help cool the body in certain conditions, this effect is much less effective during humid weather because sweat cannot evaporate as easily. Instead, the additional heat from a hot drink can add to your body's heat load when it is already working hard to stay cool.
Experts also warn that caffeine is a stimulant that can temporarily raise your heart rate and blood pressure. During very hot weather, your heart is already working harder to pump blood around the body to help release heat through the skin, meaning caffeinated drinks can place additional strain on the cardiovascular system.
Recommended alternatives and precautions
Instead, the NHS recommends drinking plenty of water and other cold drinks to stay hydrated throughout the day. People are also advised to stay in the shade where possible, avoid strenuous exercise between 11am and 3pm, eat cold foods, take cool showers, wear light clothing and keep curtains closed in rooms that face the sun to help keep homes cooler.
