How to cool down quickly: 4 surprising, science-backed ways to cope with a heatwave

Admit it: you’re currently feeling somewhere between uncomfortably warm and on the verge of spontaneously combusting. Not that we’re judging, mind. This week, temperatures are soaring in the UK, with many parts of the country experiencing an early September heatwave.

Inevitably, this heat has created a work environment that humans simply aren’t adapted for. “We’re essentially tropical animals that have evolved to be mostly naked and resting in a climate of around 26°C. We’re just not designed to be doing manual work in protective clothing in these temperatures, or sitting in stuffy offices in suits,” says Professor Mike Tipton from the Extreme Environments Laboratory at the University of Portsmouth.

So, bar turning up to work in a loincloth, how do you cool down in a heatwave? You're likely familiar with the basic tips: drink plenty of water, stay in the shade and close your curtains if things get particularly hot.

However, there are plenty of other simple, scientifically supported techniques that will help you handle the heat. Here are four of the best.

1. Cool your hands first, not your face

If you’re feeling the heat and somebody offers you a fan, it’s likely that you’ll try and cool your face first. However, according to Tipton, this is far from the quickest way of lowering your body temperature.

“Certainly, all that breeze on your face will simulate cold receptors there, which will give you a very powerful sensation of comfort. But actually, it’s not going to extract the heat from your body,” he says.

Instead, a better cooling strategy is to immerse your hands in cold water for 15 to 20 minutes. “Your hands have a high surface area to mass area – they have lots of blood flowing in them when you’re hot. If your core temperature is hot, your body will send blood to the extremities in order to lose heat,” explains Tipton.

“Immersing your hands in cold water won’t feel as nice, but it’ll cool you much faster than even an ice bath! It’s so important to make a distinction between things that make you feel cooler and things that actually make you cooler.”

2. Avoid cold showers

Sure, jumping into a chilly shower may seem tempting on a scorching summer’s day. However, abruptly immersing your entire body in chilly water is, as strange as it sounds, a very slow way of cooling your body during a heatwave.

“Putting one area of your body in cold water is fine, but cover too much surface in it, and your body will actually constrict the amount of blood that reaches your skin,” says Tipton. “The secret to cooling down is to deliver blood to your skin’s surface and then gently take away the heat.”

In short: skip the ice bath and opt for a tepid shower instead. The ideal temperature will depend on your body and the heat outside, but Tipton suggests that water that feels relatively warm is the best option.

“You want water that will achieve and maintain maximum skin flow,” he says. “You need to maximise the temperature difference between your body and the water without shutting down blood flow to the skin.”

Read more:

• UK heatwave: Are these searing temperatures the future of summers in the UK?
• Warmer weather due to climate change is eating away at our sleep

3. Opt for hot drinks

Yes, the old wives' tale is true: sipping a warm drink will cool you down faster than knocking back icy water.

“It’s not about trying to cool your body directly, but activating the systems – such as sweating, moving blood to your skin – that will,” Tipton says. “Eating a hot curry will chill your body in the same way.”

This isn’t to say that you should only drink hot fluids – staying hydrated with water of any temperature helps to cool the body through perspiration and transferring heat from active tissues to the skin. Just know that gulping down that oh-so-refreshing fridge water is unlikely to douse your internal temp quickly.

“Think about it: around 60 per cent of the human body is water – that's around 40 litres. Adding one glass of cold fluids isn’t going to make much difference. It’s a drop in the ocean,” explains Tipton.

There’s one big caveat with this hot drinks tactic, however. If you do opt for a steaming beverage, best not to make it a coffee or tea. Caffeine, along with alcohol, can raise your body's metabolic rate, causing it to generate more heat. Moreover, caffeine acts as a diuretic, leading to a faster loss of fluids from your body compared to other beverages.

In other words, it’s time to rummage out that forgotten box of mint tea tucked away at the back of your cupboard.

4. Enhance your sweat with a breeze

We get it: ‘fan yourself when hot’ hardly seems like game-changing advice. However, it’s important you fan as wide an area of your body as possible (without getting any weird looks at the beach, of course).

Why? Well, a fan doesn’t cool your body just by displacing the warm air in contact with your skin – it helps sweat evaporate too. By only fanning your face, you are limited to enhancing evaporation in a very small portion of your body.

During an extreme heatwave, this can be a big problem. “When the temperature reaches around 35°C, the only real way to cool the body is through sweating,” says Tipton.

“This is because the evaporation of sweat isn’t actually reliant on temperature – it’s all about the water vapour pressure difference between the air and the skin. A breeze helps here.”

When possible, consider using a non-electric hand fan to generate a refreshing breeze or promote natural airflow by opening multiple windows. “Relying solely on air conditioning won't do much to mitigate climate change – it’s actually a huge part of the problem!” says Tipton.