Heat stroke while running: what to know

Running produces internal heat, while humidity and heavy clothing can limit cooling. Heat stroke may cause confusion, unusual behaviour, poor balance, hot skin, headache, nausea, or collapse. It can happen even to a fit runner, and sweating may be present or absent. Heat Exhaustion has overlapping symptoms but is less severe; confusion or reduced alertness makes the situation an emergency.

Stop running and move the person to a cool place. Remove excess clothing, apply cool wet cloths or water, and fan the skin. Call emergency services and keep checking breathing. Do not let the runner return to exercise or drive themselves. Offer small sips only when fully alert and able to swallow; avoid forcing fluids during vomiting or confusion. Hospital teams may provide IV Fluid Therapy and observation.

Call immediately for confusion, collapse, seizure, breathing difficulty, repeated vomiting, or inability to drink safely. Do not wait for a watch, thermometer, or pulse reading to confirm the problem. A runner who improves after cooling still needs medical advice when heat stroke was suspected, because symptoms can recur or organ injury may not be obvious at first. Fever-like warmth after exertion is not a safe reason to observe at home.

Ask when training can restart, how to adjust pace and clothing for heat, whether medicines or illness alter risk, and which early symptoms should end a run.