Causes of heat stroke

Heat exhaustion can progress to heat stroke, but heat stroke may also appear suddenly during strenuous activity. The brain and nervous system are especially vulnerable: confusion, unusual behaviour, collapse, seizure, or loss of consciousness are danger signs. Skin may feel very hot and can be dry or sweaty, so sweating does not rule out heat stroke. Fever-like overheating can be part of the picture, but heat exposure and altered mental state make this an emergency rather than an ordinary infection. Vomiting can worsen fluid loss and make drinking unsafe.

Call emergency services immediately if heat stroke is suspected. Move the person to shade or air conditioning, remove excess clothing, and cool the skin with wet cloths, water, or cool packs while help is coming. Do not give drinks to someone who is confused, drowsy, vomiting, or unable to swallow safely. Do not leave the person alone. Hospital teams may use rapid cooling, monitoring, and [IV Fluid Therapy](/treatments/acute-and-urgent-care/iv-fluid-therapy/).

Treat confusion, fainting, seizure, severe weakness, collapse, or a very hot body after heat exposure as an emergency. Call for help even if the person briefly improves. Repeated [Vomiting](/symptoms/vomiting/), severe headache, or a high temperature after exertion also needs prompt assessment. [Heat Exhaustion](/conditions/heat-exhaustion/) symptoms should be assessed if cooling and rest do not bring clear improvement.

What made this episode more likely? How should I plan cooling, fluids, medicines, and exercise in hot weather? Do I need follow-up after emergency treatment?