Heat related illness Doctor in Mumbai Exertional heat illness occurs when athletes or workers perform intense exercise in heat. The important risk factors include high ambient temperature and humidity, lack of acclimatization, dehydration, and poor physical fitness. A number of drugs and supplements, including alcohol and stimulants, increase the risk. Heat exhaustion is characterized by the inability to maintain adequate cardiac output due to strenuous physical exercise and environmental heat stress . There is high body temperature but the consciousness is not impaired. Exertional heat stroke is a multisystem, life threatening illness characterized by impaired consciousness and additional organ damage like liver and kidney. The rapid cooling of the body is paramount. Cold immersion therapy is highly effective. The preventive measures for heat related illness include maintaining a high level of fitness, frequent breaks for hydration and cooling, avoidance of activity during severe heat and / or humidity, wearing loose fitting, lightweight clothing, protection against sunburn, intake of plenty of fluids along with added salt and minerals, never any one in parked car. The guidance from a specialist doctor should be sought for prevention and treatment of heat related illness.