Tips for Running in the Heat

Written by the rescuers and doctors of the Trail des Passerelles du Monteynard.

A few days before your next summer goal at the Trail des Passerelles du Monteynard, and before the announcer asks you “Are you ready?”, we wanted to share some thoughts on managing heat during running.

🥵 Hyperthermia: the main risk

One of the main risks when running in hot conditions is hyperthermia, which is an excessive rise in body temperature. This can lead to exhaustion, heat stroke, and in severe cases, neurological damage, organ failure, coma, or even death.

Warning signs include: headache, nausea, dizziness, chills, hot dry skin, rapid heartbeat – all signals that should alert you to slow down, cool off, and seek help immediately.

👥 Tips for the days before the race

Are we all equally affected by heat? No. Several risk factors for exertional heat stroke exist.

✅ Short-term modifiable factors:

Do not consume alcohol in the 48 hours before the race
Do not skip meals in the 24 hours before
Get proper sleep
Avoid sunburns before race day

⚠️ In case of:

Widespread sunburn
Fever or diarrhea in the days prior
👉 It is better to avoid starting the race

🚫 Painkillers:

Taking painkillers (especially anti-inflammatories) is linked to a higher risk of heat stroke.
If you need medication to run, it means you are not fit to run and should skip the race.

🏃‍♀️ Race day: what to do?

🎧 Listen to your body

Excessive pace is a major factor for heat stroke.
Do not aim for a personal record: moderate your effort and adjust your speed.
If you notice your heart rate rising or unusual shortness of breath, slow down, take a break in the shade.

👕 Clothing tips:

Wear light-colored, breathable clothing
Avoid materials that trap heat and moisture, and long clothing.

💦 Cooling down

Sprinkle water on your head, neck, and torso regularly
Wet your cap or neck gaiter
Wear technical clothing that promotes evaporation

⛑️ Follow mandatory gear rules

Refill your water supply at every aid station
Checks before and during the race will be carried out by the organization.

🤝 Help each other

If you encounter a runner in difficulty:
- Contact the rescue center
- Provide their bib number and your exact location (kilometer mark, GPS coordinates, or topographic landmark)

🥤 Hydrate and eat properly

💧 Drinking:

Regularly, in small amounts
Thirst remains a good indicator

🧂 Mineral intake:

Drink mineral-rich drinks (water like St-Yorre, electrolyte powder, sports drinks).
Eat salty foods during the race.
(drinks alone do not replace lost minerals)

⚠️ Caution:

Be careful not to drink too much, which can cause hyponatremia (too little salt in the blood).

🔍 Hyponatremia symptoms:
- Aversion to water
- Reduced alertness
- Balance issues

🚫 Do not take anti-inflammatories

Before, during, or after the race: there is no good reason to take an anti-inflammatory.
Sports are beneficial for health, as long as they are progressive and respect your body’s signals.
Using medication to “push through” is never a solution.

🧃 What about pre-race drinks?

It’s impossible to be “over-hydrated”
It’s important not to arrive dehydrated at the start area
Caffeine, having a diuretic effect, should be avoided before the start
Reserve caffeine supplements for very long efforts or technical sections

💬 In summary:
Adjust your pace, stay hydrated, listen to your body, follow instructions, and help each other.
Running in extreme heat is not about pushing for performance at all costs; it’s a challenge to manage wisely.

Dear trail runners, during this heat period, we call for vigilance, common sense, and listening to your body: stay alert, adjust your effort, and always prioritize safety over challenge.