Passengers on the London Underground during the heatwave on 26 June Guy Bell / Alamy
The heatwave that hit Europe at the end of June was the hottest ever and came less than a month after another record-breaking heatwave in May. Now, another heatwave has started that is forecast to last even longer, bringing temperatures of up to 34°C (93°F) to the UK.
To better understand the impacts of this heat, I visited the University of Brighton’s Environmental Extremes Laboratory, just across a field from the stadium of Brighton and Hove Albion Football Club, which has worked with the lab to assess players’ fitness. Spending just 10 minutes in a heat chamber was enough to show that as heatwaves get more frequent and intense, I’m not prepared – and you probably aren’t, either.
The heat chamber is a windowed room where researchers can control temperature, moisture and oxygen content, recreating the ambient conditions found at Mexico City’s high-elevation World Cup stadium or in a European city during a heatwave.
“[Heatwaves] are here to stay, and we’ve got to help people get used to preparing for heatwaves and dealing with it, not on an off-chance, but on a regular, every-year basis, on multiple occasions,” said lab director during my visit.
On a dial outside the door, Maxwell and his colleagues set the temperature to 35°C (95°F) and the humidity to 50 per cent, similar to London during the June heatwave. They measured my heart rate and blood oxygen level with a fingertip pulse monitor and my skin temperature with an infrared thermometer pistol. They also asked me to rate how hot I felt and my level of exertion.
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As we entered the chamber, the heat hit me like a wall, and I had a twinge of nervousness. What was I about to expose myself to in the name of science?
To simulate moving around outside, the researchers had me start walking on a treadmill set to a 1 per cent incline. I began to sweat, but because the high humidity was slowing evaporation, it didn’t cool me down much. In the oppressive heat, even this moderate walk became taxing.
After 5 minutes, the thermometer showed my skin temperature had risen from 33°C to more than 36°C. My body was shunting warm blood from my core to my skin to try to shed heat, explained Maxwell.
Reporter Alec Luhn in the heat chamber at the University of Brighton’s Environmental Extremes Laboratory Bill Norton
My heart rate had also jumped, from 72 beats per minute to 81 beats per minute. As I sweated out water, my blood was thickening, forcing my heart to pump harder.
After 10 minutes of plodding, I was feeling tired, and my heart rate had reached 95 beats per minute. I felt light-headed as Maxwell helped me off the treadmill and into a chair outside the chamber.
I asked him how I’d done. “You’re not heat-adapted,” he said. Even relatively healthy people can be at risk, he added.
Maxwell handed me a strawberry ice pop, which not only tasted heavenly, but also started cooling my body from the inside. Then he had me plunge my hands into a tub of cold water. The hands, feet and ears have dense concentrations of arteries, veins and capillaries. Targeting those areas can cool large flows of blood.
“We get people’s temperature to drop so much quicker by using that method,” said Maxwell.
Simple actions like taking a cool shower – not too cold, or the blood vessels will constrict – can be surprisingly effective. But surveys Maxwell and colleagues are doing show that only a small fraction of the UK population takes measures for protection from the heat. He pointed out that I had come without a water bottle, even though it was a warm day.
In the long term, we need to teach people how to improve their bodies’ heat tolerance, according to Maxwell. To start with, aerobic exercise like jogging makes your heart better at moving blood to the skin. Then there’s heat exposure. A one-person sauna tent was standing off to the side of the lab. Regular sauna sessions can teach your blood vessels to dilate quickly and your skin to sweat more. Your sweat even gets less salty, preserving your electrolyte levels.
“The narrative at the moment is [that] we’ve got to get rid of heat; heat is bad, bad, bad,” said Maxwell. “I think we need to change that narrative to: safe heat can actually be therapeutic.”
After I got home, my head hurt, and I felt hot and thirsty. I decided I need to go to the sauna more. As for the jogging, well, I’ll work on it.
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