Preventing heat exhaustion

Heat exhaustion happens when the body loses too much fluid and salt through sweating and cannot cool itself effectively. Hot, humid conditions, direct sun, heavy clothing and strenuous work increase the load. Dehydration, certain medicines and health conditions can make heat harder to tolerate. Heat intolerance can also have causes unrelated to weather, so repeated difficulty coping with ordinary temperatures deserves assessment.

Plan outdoor work and exercise for cooler periods when possible. Rest in shade or air conditioning, wear light loose clothing and use a hat or umbrella in direct sun. Drink regularly rather than waiting for excessive thirst, and replace fluids after heavy sweating; ask a clinician what is suitable if you have heart, kidney or fluid-balance problems. Never leave a child or dependent adult in a parked vehicle. Build up activity gradually during hot weather and check on older people, babies and anyone working outdoors.

Move to a cool place, loosen clothing, apply cool wet cloths and sip fluids if someone develops excessive sweating, headache, dizziness or marked thirst. Get urgent help if the person becomes confused, faints, has a seizure, cannot drink, or remains unwell after cooling; these signs may indicate life-threatening heatstroke. Dark urine, worsening weakness or persistent symptoms also need medical assessment.

Ask whether your medicines or health conditions affect heat tolerance, how much fluid is appropriate for you, and which symptoms should trigger urgent care.