Running in humidity can make the heat feel worse, posing challenges for runners. Runstreet reports that high humidity intensifies heat and makes it harder for the body to cool down. This can slow down pace and increase the risk of heat-related illnesses.

Marnie Kunz, a certified run coach, emphasizes the importance of understanding how to run in humid conditions. She has studied humidity extensively and offers guidelines to help runners calculate when it's too hot and humid to run outside. Scaling back workouts or proceeding with regular training depends on these factors. Read more travel coverage.

Kunz advises runners to be aware of the effects of humidity on their bodies. High humidity can make runs feel more difficult and increase the toll on the body. By following her tips, runners can stay safe and maintain their performance even in challenging conditions. Related: Summer Running Tips to Stay Motivated and Cool.

This original Runner World brief is based on reporting from Runstreet. Visit the source for its complete reporting, context and any later corrections.