Types of Heat Exhaustion

Early heat exhaustion may feel like unusual thirst, heavy sweating, tiredness, headache or muscle cramps. As fluid loss increases, dizziness, nausea, weakness, a fast heartbeat and dark urine may appear. Heat intolerance can make hot environments harder to tolerate, but it does not by itself confirm heat exhaustion.

The illness can develop during exercise, outdoor work, travel or time in a hot room. Dehydration makes cooling harder, especially when sweating is heavy. Heat exhaustion is different from heatstroke: confusion, collapse, seizures or a very high body temperature are emergency signs rather than symptoms to manage at home.

Stop the activity and move to a cool, shaded or air-conditioned place. Loosen extra clothing, rest and cool the skin with a fan, cool wet cloths or a lukewarm-to-cool shower. Sip water or an oral rehydration drink if you are awake and able to swallow.

Do not return to strenuous activity while symptoms remain. Someone should stay with the affected person and watch for worsening alertness, vomiting or inability to drink. Children, older adults and people with long-term illnesses may need earlier medical advice.

Call emergency services for confusion, fainting, seizure, severe weakness, breathing problems, inability to drink or a suspected heatstroke. Get medical advice if symptoms do not improve after cooling and fluids, or if vomiting prevents rehydration. Dark urine that persists can also indicate significant fluid loss.

Ask whether medicines or a health condition increase your heat risk, how much activity is sensible while recovering, and which fluid replacement option is appropriate for you.