Annie Thorén conquering the sunshine.

How to exercise in the extreme summer heat

© Pedro Gomez

Pro tips on how to go about training when summer temperatures are reaching new highs.

All over Europe, summer temperatures are reaching new highs and in many places it’s the hottest summer on record for hundreds of years. The blue skies and sunshine is to many people’s delight, but how do you go about training in such high temperatures? Is it dangerous? We caught up with Swedish triathlete Annie Thorén, someone more than used to long hours of exercise in extreme temperatures, to figure out the do’s and dont’s when exercising in the heat. Keep reading for her best tips.

Is it dangerous to exercise in the heat?

“Opposite to what many believe, it is not actually dangerous to exercise in the heat. What can be dangerous is HOW we handle the heat. Nutrition and preparation is key. Take Ironman Hawaii for example, people who bonk during the race are not doing it because they haven’t trained hard enough, it’s because they’ve got their nutrition plan wrong on the day and not had enough gels, salts and water for the body to keep functioning properly. As long as you plan your training regime properly, there is nothing stopping you from enjoying this summer’s hot weather.” – Annie Thorén
Running is one of the hardest things you can do in the heat.
Running is one of the hardest things you can do in the heat.


1. Plan when in the day to exercise

Maybe the most simple, but also important advice is to choose the right time of day to exercise. When temperatures are reaching high 20’s or even goes into their 30’s it is smart to either head out early in the morning or late at night when temperatures are lower, to avoid the midday heat.

2. Plan where to exercise

Always choose shaded areas over places with direct sunshine. If you haven’t tried trail running yet for example, this is the perfect summer to give it a go.
“In cities the heat gets stuck in-between houses and temperatures rise even more, so I’d recommend heading into the forest instead of the road or the city if you’re going running”.

3. Keep your head cool

The most important body part to keep cool is the head, as otherwise you tend to get extremely tired. 
"A good tip is to use a cap that you soak in water every so often, to keep the head as cool as possible".
Annie trying to keep cool using a sponge with cold water.
Annie trying to keep cool using a sponge with cold water.

4. Plan when and what to drink

It is important to have a proper plan when and what to drink, especially if you’re doing long endurance-based sessions, but even if you’re just heading to the gym you should bring a drink with you when it is really hot outside. Since you’ll be sweating more than usual you should add extra electrolyte tablets, sport drinks or rehydration sachets to your water, to add salts back to your body.
“There are plenty of good options out there: sport drink companies have massive ranges of products that you can use and even the rehydration tablets you find at your local pharmacy are great for exercising”.

4. Add extra salt to food and drinks

Normally we are told to use less salt in our food, but during hot days, and especially when exercising regularly, it is actually smart to salt your food a little extra. You can even add normal salt to your water bottle, for an extra boost.
“Salt is really important as Sodium (found in salt) binds to water in the body and helps maintain the balance of fluids. If the salt levels are too low your body can’t bind to anything, which makes you tired and swollen – something that happens to women more often than men. So if you sweat a lot, don’t forget to keep your salt levels healthy”.

5. Drink 750 ml an hour

When out riding you should consume a big bottle every hour - that is 750 ml of fluids. A smart tip is to mount two bottle holders on your bike so that you don’t have to stop every hour for a refill.
“I tend to have one bottle with plain water and one with sports drink when I am doing big rides, but in this abnormally hot weather I have actually had one bottle with sports drink and another one with sports drink plus a rehydration tablet to keep the correct salt levels in my body level.”

6. If you sweat at night, drink more in the morning

Something many forget about is that during hot nights we sweat in our sleep, which means that we start our days on minus (on the hydration scale). Thus, you have to start the day with water – preferably with some kind of rehydration tablet as well.
“Normally, when it is less hot outside and we’ve had a good nights sleep and enough to eat and drink the day before, we start our day on plus. Then it is totally ok to go for a run before breakfast, but not when it is this warm - then you have to drink water with rehydration tablets before heading out”.

7. Avoid caffeine during training sessions

Never start a hot weather session with caffeine, as it is makes you pee more often. In hot weather your body needs to retain fluids, not get rid of them.
“During an Ironman for example, athletes tend to drink caffeine towards the last hour of the race to keep going, not at the start”.

8. Divide your long running sessions into shorter laps

Running is the hardest and toughest thing to do in the heat. It is not healthy to do long runs in one go, and it is important to have a drink plan in place before you head out. If you’re going to run 21 km, do it in three laps – so you run 7 km three times – and drink water in-between each lap.
“The other day, I set up a water stand at home and then ran past it three times during my run so that I could keep hydrating. I basically ran home, drank 5-6 big sips, and then headed out for the next lap. During any session longer than 5 km you need to drink water.”

9. Don’t bring water along if it affects your running technique

Why set up a water stand then - why not just bring water with you? Well, running with a heavy backpack, bottle or similar not only ruins the running experience it is also bad for your running technique.
“I see many people running with hydration packs or even with big heavy bottles in their hands, and I’ve never understood how they can do it. It is not only annoying but it also really bad for your body as it misaligns you when running. A bottle in one hand makes you wonky, and a backpack will change the position of your back – and it’s going to affect your running technique, which can lead to injury. If you’re going to be out running for 90 minutes, and have to bring water with you, my advice is to invest in a really good, ergonomic pack in that case. Otherwise, do shorter laps with water stops.”

10. Remember that you sweat when swimming

When temperatures on land reach new highs it is tempting to cool off with a swim rather than a run or cycle. It is important to remember, however, that you sweat even in the water (although you don’t feel it) so it’s equally important to keep hydrating when swimming.
It's important to hydrate when swimming too.
It's important to hydrate when swimming too.
“This summer all the lakes are so warm that you’ll actually end up sweating more than normal, and thus rehydration becomes even more important. It can be hard to rehydrate when swimming in open water, but if you’re doing laps in a pool always have a bottle of water with you that you can sip on during your session.”

Good luck and enjoy the weather while it lasts!

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