Heat Stroke vs Heat Exhaustion: The Difference That Can Save a Life in Indian Summers

Every summer, Hyderabad's temperatures exceed 40–44°C, and heat-related illness sends hundreds to hospital. The spectrum ranges from heat cramps (muscle spasms from salt loss) and heat exhaustion (fluid and salt depletion) to heat stroke — a life-threatening neurological emergency with core body temperature above 40°C and brain dysfunction. Knowing the difference and knowing what to do can determine survival.

Heat Exhaustion — Warning Stage

Heat exhaustion is the body's decompensating response to heat and fluid loss — but the brain is still functioning. Features: heavy sweating; cool, pale, moist skin; fast, weak pulse; nausea or vomiting; muscle cramps; tiredness and weakness; dizziness; headache; fainting. Core temperature is elevated but below 40°C. The person is awake and mentally appropriate.

First aid for heat exhaustion: Move to cool, shaded or air-conditioned environment immediately. Lie down with legs raised slightly. Remove excess clothing. Cool the body: wet cloths on the neck, armpits, and groin; fan; cool water to drink if conscious and not vomiting. ORS solution or sports drink — replacing both water and electrolytes. Monitor closely. Most people recover within 30 minutes of cooling.

Heat Stroke — Neurological Emergency

Heat stroke occurs when core body temperature exceeds 40°C AND the brain is affected. It is a multi-organ emergency with mortality of 10–50% even with treatment. Two types:

Classic heat stroke: Occurs in vulnerable people during sustained heat (elderly, infants, those with chronic illness or on diuretics, psychiatric patients on antipsychotics). Skin is often hot and DRY (sweating mechanism fails). Mental confusion, slurred speech, seizures, or loss of consciousness.

Exertional heat stroke: Occurs in young, fit people during intense physical activity in heat — athletes, outdoor labourers, military recruits. Skin may still be sweating. Sudden mental status change during or after intense exertion in the heat.

Emergency response — call 108: Immediate aggressive cooling is the treatment — every minute of high core temperature causes more brain damage. Ice water immersion (most effective if available). Wet towels on the neck, armpits, groin. Fan vigorously. IV fluids. In hospital: cooling blankets, IV fluids, treatment of complications (rhabdomyolysis, DIC, acute kidney injury, seizures).

Brain Consequences of Heat Stroke

The cerebellum is the brain region most vulnerable to heat damage — surviving heat stroke patients sometimes have permanent cerebellar ataxia (coordination problems and balance difficulty). Early aggressive cooling dramatically reduces permanent neurological injury.

Prevention: stay hydrated (drink before feeling thirsty in the heat); schedule outdoor activity before 8AM or after 6PM; wear loose, light-coloured cotton clothing; never leave children or elderly people in parked cars. For neurological emergencies: Sri Anand CNC, Chanda Nagar, Hyderabad. Call +91 90633 66983.