Why can running in hot weather be dangerous?
Summer makes you want to push yourself to the limit: the trails are dry, the scenery bright and the outings longer. But when the temperature rises, your performance is affected and the dangers appear.
Exercise-induced hyperthermia: definition and risks
When you run, your body heats up. That's normal. But sometimes you get too hot.
Usually, you get rid of it by sweating, breathing and circulating your blood. But when the air is hot, humid and windless, this regulation is no longer enough.
That's when exercise-induced hyperthermia sets in. Your internal temperature rises above 39°C, your body goes into overdrive, you sweat profusely... your performance plummets, your head spins, and you sense that ‘something's not right’.
If you ignore the signals, you fall into a second, much more dangerous stage: heatstroke. Your nervous system starts to malfunction, and you may stop sweating, feel nauseous, have headaches, lose coordination and even lose consciousness.
The consequences can be serious if you don't stop immediately, cool down and sometimes seek further treatment.
Other symptoms you should never ignore
Other symptoms, sometimes more discreet, may appear during your outing, and it's important to pay attention to them when it's hot.
- An unusual sensation of heat inside, even at a moderate pace
- A reduction in your ability to concentrate
- Shivering, paradoxically, or hot but dry skin
- An abnormally high heart rate at rest
- Persistent cramps, even after hydration
If you experience one or more of these symptoms, stop immediately. Drink, find shade, cool off and get help if you need it.
Running in the heat: precautions to take
As you will have realised, running in temperatures of over 30°C takes preparation. Here's how to continue enjoying the trails while limiting the risks.
Plan Ahead to Cope Better
When the temperatures rise, every run requires a bit of strategy.
- Adjust your schedule: run in the morning or evening. Between 11am and 5pm is a no-go.
- Favour short, low-intensity outings, especially during the first hot spells.
Hydrate and Fuel Smartly
Water is essential, but not always enough. And most importantly, it should come before thirst strikes.
- Drink regularly, every 15 to 20 minutes. Even if you’re not thirsty.
- Add electrolytes (or a pinch of salt) to make up for lost minerals.
- Don’t forget carbs on long runs: your body uses up more energy in the heat.
Mistakes to Avoid
Heat can be trickier than the terrain. So be careful with:
- Overdressing: opt for breathable, light-coloured and ultra-light fabrics.
- Running alone without telling anyone: always let someone know, and carry a phone.
- Ignoring warning signs: dizziness, nausea, disorientation… your body is speaking to you — listen.
- Sticking rigidly to your training plan: the weather doesn’t follow any plan — adapt, or it’ll hit you back.
Gearing Up for Summer: Your Best Ally Against the Heat
Over 30°C, choosing the right gear isn’t about comfort — it’s about strategy. So prioritise:
- Sahara cap: it protects your head, but most importantly your neck — a key zone for regulating body temperature. Forget the look, think survival.
- Sunglasses : not just for style. They reduce eye fatigue, lower the risk of headaches, and protect against UV rays on long outings.
- Breathable technical fabrics: choose ultra-light materials that wick away sweat, dry fast, and don’t cling to your skin. A t-shirt that holds moisture turns into a mobile oven.
- High-protection sun cream: especially for ultras or exposed terrain. Think it interferes with sweating? Poor excuse. Second-degree burns will slow you down far more.
Raidlight’s Commitment
At Raidlight, we design each product with one goal: to help you go all the way, no matter the weather. Whether you're on a morning 10K or enduring a blazing ultra, we're here to kit you out.
From the Moroccan desert to the GR20 in the height of summer, our gear has proven itself in the toughest races. Just ask Merile Robert — 7-time finisher and 2-time podium on the Marathon des Sables®. He knows what we’re talking about.
What we prioritise:
- Lightweight, breathable, and durable materials
We use antibacterial and antistatic materials, combined with Quick-Dry technology to wick sweat more effectively, keep you cool, and limit odours.
Our most technical fabrics go down to 65g/m², with some shirts under 50g — no compromise on lightness or durability.
Such density, combined with polyester, also allows for ultra-fast drying.
- Ergonomic design
Our textiles are never meant to get in your way — we favour a close fit without compression, seamless finishes, and micro-perforations for maximum breathability where your body heats up most.
- Eco-conscious commitment
We incorporate recycled materials in an increasing share of our products. Our Made in France collection grows each year to ensure quality, durability, and short supply chains.
Conclusion: Heat or Not, You Keep Moving Forward
Running in the heat isn’t madness — it’s a choice. But it’s a choice that demands more awareness, and most importantly, gear that keeps up.
