A must for nature lovers, hiking is hugely popular in summer. Yet heatwaves can pose real dangers. Taking the necessary precautions is essential to enjoy the trails safely. Here is everything you need to know about hiking in the heat.
What are the risks of heat when hiking?
Hiking in high temperatures, especially during a heatwave, presents several hazards. The most serious is heat stroke, or hyperthermia. It occurs when the body can no longer regulate its temperature, causing high fever, severe headaches, nausea, vomiting, and confusion. Without prompt treatment, it can lead to fainting, loss of consciousness, or even death.
In high heat, your body loses large amounts of water through sweat while hiking. Without adequate hydration, you risk suffering from dehydration. Symptoms vary in severity and typically include intense thirst, unusual fatigue, dizziness, or headaches.
Another less common risk is hyponatraemia, caused by a lack of salt. It can occur if electrolyte loss is not replenished. Although rare, it is dangerous and can affect brain function.
Finally, sunburn poses a real danger to your skin. Beyond the immediate discomfort, it can cause long-term health issues, including premature skin ageing and an increased risk of skin cancer.
When should you set off to avoid the heat?
To beat the heat while hiking, we recommend adjusting your summer schedule. Temperatures typically peak between 12 pm and 4 pm, when the sun is highest and the air is warmest.
The best way to avoid the heat is to set off very early and finish your hiking trip before midday. You’ll benefit from cooler air and quieter trails, while significantly reducing the risk of feeling unwell.
Another great option is to set out in late afternoon or early evening—just remember to bring a headlamp and monitor the time so you are not caught out after dark. Heading out at these unusual hours is a fantastic way to experience the mountains from a fresh perspective.
If you’re hiking all day, take a break in the shade in the early afternoon to recover and let your body temperature drop before setting off again.
During a heatwave, it may be wiser to cancel your hiking trip. If temperatures exceed 30 or 35°C, the route has long stretches in direct sun, or some participants are not in good physical condition, we suggest postponing your outing for safety.
How to stay safe from the heat when hiking?
Along with adjusting your departure times, several practical tips will keep you safe from the heat when hiking. Adapt your route, fine-tune your gear, stay well hydrated, and protect your skin.
Apply SPF 30 to 50 sunscreen regularly to every part of your body exposed to the sun. Don’t forget areas often missed, such as your ears, neck and the backs of your knees. As well as drinking frequently, take time to cool down while hiking. For example, dip your forearms or the back of your neck in a stream, or wet your cap, hat or neck gaiter.
The best way to protect yourself from the heat when hiking is to adapt your route. Choose a circuit with plenty of shaded areas. In summer, woods provide the perfect protection against the sun. You can also walk near a stream or lake to cool down if needed. Remember to take frequent breaks in the shade.
To avoid unnecessary risks, adjust your route to the temperature. Skip steep climbs and demanding hikes in favour of gentler walks at a moderate pace.
How to stay properly hydrated when hiking?
Staying hydrated is vital in high temperatures, especially when hiking. Drink enough water before you set off and identify water sources along your route. As well as carrying enough water for your hike — at least 2 litres — you can take a filter bottle, purification tablets or a water filter.
Throughout your effort, remember to drink regularly in small sips. Never wait until you feel thirsty to hydrate: thirst is already a sign of dehydration. We recommend using a hydration bladder or an easily accessible water bottle so you can drink continuously on the trail.
When choosing what to drink, stick to water and avoid sugary drinks or alcohol. To prevent hyponatraemia, add a pinch of salt to your water or take isotonic drinks or electrolyte tablets to replace lost minerals.
For a long day of hiking, prepare light meals that are easy to digest. Pack snacks with a high water content (fruit, fruit purées) and quick-release sugars (dried fruit, cereal bars).
After hiking, drink mineral-rich drinks, sparkling water or diluted fruit juice to help you recover.
What clothes should you wear in a heatwave?
Clothing can help protect you from the heat when hiking. It should be lightweight, breathable and offer good coverage to shield you from the sun. Light-coloured fabrics are generally recommended because they reflect light rather than absorb it.
Choose breathable technical T-shirts that cover your shoulders. If you expect prolonged sun exposure, long sleeves are a good alternative. Lightweight synthetic fabrics or merino wool help wick away sweat, while cotton should be avoided. For extra protection, you can also choose UV-protective clothing designed to shield you from the sun’s rays.
Your bottoms should be comfortable and airy. Wear shorts or lightweight trousers, depending on your exposure to the sun, brush, and ticks. Convertible trousers are a great compromise in summer. In all cases, opt for stretch, breathable fabrics.
To protect your head, hiking caps and hats are essential. Wide-brimmed hats also cover your face and neck. Category 3 or 4 sunglasses are essential for protecting your eyes.
Finally, do not forget technical-fibre socks. They wick away sweat and reduce friction. Choose low-cut hiking shoes and avoid waterproof models, which tend to retain heat.
As you can see, hiking in the heat is completely doable, as long as you prepare properly. Adjust your schedule, gear, and route to make the most of the trails. In extreme heatwaves, do not hesitate to postpone your hike for safety.
