Running in the heat

Heat makes your heart work harder for the same pace: slow down and run by effort or heart rate, not by pace.

• From about 20 °C you slow down; beyond 25 °C, 20 to 30 seconds per km slower is normal, more if it’s humid.
• Run early in the morning or late in the evening, in the shade, in light-coloured clothing, with a cap and sunscreen.
• Drink to thirst, carry water beyond about 45 minutes and add salt if you sweat a lot.
• Your body adapts after 10 to 14 days of regular runs in the heat.

Stop and cool down at once if you feel dizzy or nauseous, or get a headache or chills: these are signs of heat illness. Confusion or fainting calls for emergency help.