Summer heat is no reason to stop running. But high temperatures change the way your body responds to exercise: your heart rate rises faster, you lose more fluid, and the risk of overheating increases. In this article, we’ll look at the key steps that can help you adapt to hot-weather conditions and keep your training both safe and effective.
Why Running in the Heat Feels Harder
When you run, your body cools itself through sweating. In hot weather, your heart has to work harder to deliver blood to your muscles while also helping regulate your body temperature. As a result, even your usual training pace can feel more demanding.
Fluid and electrolyte loss can also make fatigue set in sooner, reduce endurance, and increase the risk of heat exhaustion. To make hot-weather running more comfortable and safer, follow these key recommendations.
1. Schedule Your Runs for the Cooler Parts of the Day
The best time to run is before 9:00 a.m. or after 7:00 p.m., when the sun is less intense. If the air temperature reaches 30°C or higher and humidity is above 70%, it’s better to move your daytime workout to a cooler time.
In high humidity, sweat evaporates more slowly, which makes it harder for your body to cool itself efficiently. That’s why 28°C with humidity above 80% can feel much more challenging than the same temperature in dry conditions.
2. Choose Gear That Helps Keep You Cool
What a Basic Runner’s Kit Looks Like
For summer runs, technical apparel made from polyester, polyamide, or other synthetic moisture-wicking fabrics is the best choice. Unlike cotton, these materials do not hold on to sweat, dry faster, and help your body maintain a more comfortable temperature. Look for labels such as moisture-wicking, Dri-FIT, HeatGear, ClimaCool, Aeroready, or similar performance technologies.
If you run in direct sunlight, choose lightweight, light-colored clothing with UV protection instead of an open singlet. Don’t forget a cap, sunglasses, and SPF 30–50 sunscreen.
3. Choose a Shaded Route with Access to Water
In direct sunlight, asphalt can heat up to 50–60°C even when the air temperature is around 30°C. That’s why running in a park or wooded area, where there is more shade, often feels much more comfortable. If you’re planning a long run, think ahead about where you can refill your water or cool down along the way.
4. Adjust Your Running Pace
Don’t compare your summer runs with your spring or autumn training. In hot weather, your pace will naturally slow down, and you should be prepared for that. Focus on how you feel or use your heart rate as a guide. If your heart rate is already 5–10 beats per minute higher than usual at the start of your run, reduce the intensity or shorten the distance.
5. Give Your Body Time to Adapt
If the heat arrives suddenly or you’re returning to running after a break, don’t start with high-intensity workouts. Full heat adaptation usually takes 7–14 days.
Begin with shorter runs or reduce your intensity by about 20–30%. For example, if you normally run 10 km, cut the distance to 7–8 km during the first few hot days, or slow your pace. Once your body adapts, you can gradually build back up to your usual training load.
6. Don’t Wait Until You Feel Thirsty
Maintaining proper fluid balance before and after your run is important. Image from pexels.com
Start your workout without feeling thirsty — this is one sign that you are adequately hydrated. About 15–20 minutes before your run, you can drink around 200–300 ml of water. After runs lasting up to an hour, water is usually enough. If your workout lasts 60–90 minutes or you sweat heavily, make sure you also replace electrolytes.
Electrolytes are minerals — mainly sodium, potassium, and magnesium — that your body loses through sweat. You can replenish them with:
- isotonic drinks, such as Powerade, Gatorade, or Isostar Hydrate & Perform;
- dissolvable electrolyte tablets, such as SIS Hydro, High5 Zero, or Nuun Sport;
- powders or sachets, such as Precision Fuel & Hydration, Maurten Drink Mix, or Isostar.
Choose the format that works best for you, but remember: electrolytes do not replace water. They help restore the minerals lost through sweat.
How to Recognize Overheating During a Run
In hot weather, it’s important not to ignore your body’s warning signs. If you notice any of the following symptoms while running, stop your workout immediately:
- dizziness or loss of balance;
- a severe headache;
- nausea or vomiting;
- sudden weakness or a feeling that your legs “won’t respond”;
- muscle cramps;
- chills or hot, dry skin;
- confusion or disorientation.
These symptoms may be signs of heat exhaustion or heat stroke. If this happens, move to a cool or shaded area, stop all physical activity, drink cool water in small sips, and try to cool your body with cold compresses or a damp towel. If you don’t start to feel better within 15–30 minutes, or if your symptoms get worse, call emergency medical services.
On the IKS blog, we regularly share running tips, advice for athletes, insights for sports event organizers, and useful content for anyone who leads an active lifestyle. Read our latest articles and stay up to date with the world of sport.
