How Hot Is Too Hot? Here’s What to Consider When Exercising in the Heat

• There is no single temperature that automatically makes exercise unsafe because humidity, direct sunlight, and airflow often influence heat stress as much as the temperature itself
• Your body maintains a core temperature near 98.6 degrees F, but exercise and hot weather together increase heat production, raising the risk of heat-related illness when heat builds up faster than your body can release it
• Early warning signs such as headaches, dizziness, muscle cramps, weakness, and unusual fatigue often appear before a heat emergency develops, giving you an opportunity to cool down and recover before the situation becomes dangerous
• Most people adapt to exercising in hot weather within about four to 14 days, making gradual increases in workout duration and intensity one of the most effective ways to improve heat tolerance
• Simple strategies such as exercising during cooler hours, staying hydrated throughout the day, wearing lightweight clothing and responding quickly to warning signs help you stay active safely even during the hottest months of the year