Extreme heat affects your brain more than you think – here’s how experts say you can protect it

If you’ve been feeling a little off during the heatwaves, you’re certainly not alone. And with the UK now sweltering through another heatwave, you’ve had plenty of opportunity to notice it.

Perhaps you’re finding it harder to concentrate, simple tasks are taking a little more effort or you’ve walked into a room only to completely forget why you’re there. As temperatures climb, our brains have rather more pressing business to attend to than keeping us feeling sharp.

That’s because hot weather can have a major effect on the brain’s ability to function normally. Behind the scenes, it’s working overtime to keep the body cool – and regulating our temperature is considerably more complicated than simply flipping a switch.

“We sweat more, lose water and salts and send more blood towards the skin so that heat can escape,” explains Dr Ramon Velazquez, a neuroscientist and scientific advisor at Mind Lab Pro. And all of that requires a huge amount of energy.

With so much of the brain’s resources being directed towards keeping us cool, other functions can start to feel the squeeze. So if your thinking feels a little foggier when the mercury rises, there’s a very real reason why – and, importantly, there are things you can do to help protect your brain in the heat. We asked three brain experts about what is going on in our heads, how this relentless hot weather affects our brain and exactly what we can do to keep it working next time the temperatures soar?

Experts:

• Dr Ramon Velazquez, a neuroscientist and scientific advisor at Mind Lab Pro
• Dean Burnett, neuroscientist
• Eloise Skinner, psychotherapist and author

How does the hot weather affect the brain?

When we get really hot, our concentration often suffers first, Dr Velazquez explains. Maybe you read something and immediately forget what it said or you open your phone and can’t remember what you were going to do next. Studies have confirmed that this is because heat impacts short-term memory.

“When you’re hot, it is a constant sort of irritant,” neuroscientist Dean Burnett explains. “The brain is just focused on the fact that you are hot.” And so, we just don’t have the bandwidth for much else. Similar to if you’re experiencing the searing pain of a twisted ankle – it’s very hard to focus on what’s going on around you.

Feeling a little grouchy in the hot weather? Heat can also shorten people’s patience. Again, this is a case of the brain not having enough power to regulate our normal functions – including regulating our emotions. As our brain tries to cool down the body, stress hormones (cortisol) is also released, heightening emotions further.

Author and existential therapist, Eloise Skinner adds that moodiness can also be exacerbated if we’re struggling to sleep in the heat. The hot weather can mean we have less effective sleep levels. And when we don’t sleep as well, our brains struggle to regulate our emotions as effectively and we become more reactive.

Thankfully there are some methods we can implement to reduce the effects of the hot weather on the brain.

How can you keep your brain working when it’s hot outside?

As much as we might like to, it might not be practical to keep an ice pack attached to your head as you go about your day. But you can still protect your brain by assisting your body in managing the heat.

1. Take breaks from the sun

As our brain is busy with other things, the heat can slow down our reactions. This can really matter if you are driving, working outside, exercising or using dangerous equipment, Dr Velazquez says.

“People sometimes try to push through because they want to finish what they started. That is exactly when errors happen,” Dr Velazquez says. The longer you stay out in the sun, the less reliable your brain will be.

And so it’s important to take lots of breaks and move into the shade if need be.

2. Keep a water bottle handy and consume water-dense foods

Your garden might be parched, but you don’t have to be. Drinking enough water during a heatwave is very important to reduce the risk of dehydration, which is closely linked to the health of your brain.

“Since the brain is around 75 per cent water, it relies on sufficient hydration to operate well,” Skinner explains. “In summer, even losing small amounts of fluids can be enough to experience an impact in cognitive performance and general mental health.” Dehydration can negatively impact tasks involving attention, executive function and motor coordination, she adds.

Dr Velazquez advises keeping water where you can see it, adding: “A bottle hidden in a bag is very easy to forget.”

Eating water-rich foods like fruit and salad like cucumbers can support hydration too, Skinner adds.

3. Eat enough key nutrients

We often lose our appetites when it’s hot outside as the body is shifting energy towards cooling the body down and away from digesting food – so we feel fuller for longer.

But it’s important we eat enough of the key nutrients including carbs for energy and omega-3 fats for supporting cell health in the brain. When we don’t eat enough key nutrients, the brain can’t work at full capacity. You might struggle to sit down to a big lunch or dinner when the heat is sweltering, but try eating smaller, more regular meals to keep your nutrients up.

Check out our no-cook recipes for some summer inspiration, all simple assembly jobs that are perfect for heatwave dining.

4. Get a fan

Fans sometimes get a bad press because they just “move the hot air around”. However, Burnett points out that good fans do actually provide cooling benefits. “That movement is actually the important part,” he explains. “It takes the sweat off your body, which causes you to cool down.”

It works the same as a lowering your car window as you drive – the temperature outside isn’t necessarily cooler than inside the car, but it creates a breeze. This moving air helps the body manage the heat and protects the brain’s functioning ability.

5. Prioritise ‘thinking’ work in the morning

Keep your brain from working too hard by keeping ‘thinking’ or creative work to the earlier, cooler parts of the day when possible, Dr Velazquez says. This can help your brain from being overworked when it’s too hot and your brain is struggling to keep up.

“When you notice yourself making silly mistakes, take that as a sign to cool down rather than forcing your brain to keep going,” he adds.

6. Keep your bedroom cool as possible

To be able to drift off to sleep, our bodies need to drop slightly in temperature. When we’re hot, and our homes are hot, that becomes difficult. And a lack of sleep can only worsen the effects the hot weather can have on the brain. This becomes especially notable when heatwaves last for multiple days, as the UK has experienced this summer.

There are simple, familiar tips to help keep cool at bedtime. Dr Velazquez recommends closing the curtains while the sun is strongest and then opening the windows when the air outside becomes cooler.

You should also use light bedding and sleep in the coolest room available. “Even one night of better sleep can make the next hot day feel more manageable,” he adds.

Be wary of serious effects

While many of the cognitive effects of hot weather are common and temporary, we do need to keep an eye out for serious effects that heat can cause.

“Sudden confusion, slurred speech, fainting, a seizure or an extremely high body temperature is different,” Dr Velazquez says. “Those signs may point to heatstroke and require emergency medical help.”

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