In humid air, sweat evaporates slowly, so your body struggles to cool down. The same run feels much harder at 2 pm than at 7 am, and that's not just in your head.
Train at the cooler ends of the day
Early morning or after sunset is best for outdoor running and sport. For midday sessions, go indoors or under a fan.
Drink before you're thirsty
- Drink a glass of water in the hour before training.
- Sip regularly during sessions longer than 30 minutes.
- For sweaty sessions over an hour, add electrolytes or a salty snack afterwards.
- Pale yellow urine is a good sign you're hydrated.
Ease off
Slow your pace by 10 to 20% on very hot days and judge effort by how you feel, not by your usual times. If you've just arrived from a cooler country, give yourself one to two weeks to adapt.
Know the warning signs
Heat exhaustion: heavy sweating, dizziness, headache, nausea, cramps, weakness. Stop, move somewhere cool, drink water and rest.
Heat stroke is an emergency. Confusion, slurred speech, fainting, or hot skin that has stopped sweating means call 999 immediately and cool the person down with water and fanning while you wait.