Heat stroke and heat exhaustion: Early signs to watch for, plus preventive tips

Heat stroke health risks: It starts with dehydration, fatigue, and muscle cramps. If exposure continues, symptoms worsen into heat exhaustion, which includes nausea, vomiting, heavy sweating, and weakness

With climate change becoming a cause of concern, India is facing longer, harsher, and more dangerous summers. The frequency and severity of heatwaves are rising each year, pushing public health systems to the edge. From dehydration and heat stroke to long-term cardiovascular stress, the impact on human health is growing rapidly.

India’s heatwaves, once restricted to the northern plains, are now a pan-India threat. Climate change is no longer just an environmental concern, it is a growing public health emergency, says Dr Sandeep Gore, Director-Emergency Medicine, Fortis Hospital Mulund & Chairman, Emergency Medicine Council, Fortis Healthcare. “Even traditionally cooler coastal cities like Mumbai have witnessed an alarming rise in heat emergencies. Last April, our emergency department received patients with heat stroke, a condition previously rare in Mumbai. These emergencies require quick recognition and immediate treatment, as delayed intervention can lead to severe complications and very high mortality,” he cautions.

The India Meteorological Department (IMD) defines a heatwave as temperatures above 40°C in plains, 37°C in coastal regions, and 30-32°C in hilly areas. “In Mumbai, humidity worsens the risk, because it hinders the body's natural cooling through sweat evaporation, leading to heat retention and increased internal body temperature.”

Also read | Heatwave alert: 9 tips to avoid heatstroke, stay healthy as temperature crosses 42°C

Warning signs to emergencies:

Heat-related illnesses develop in stages. At first, people may feel dehydrated, tired, and suffer muscle cramps, these are signs of heat cramps. “If exposure continues, symptoms worsen into heat exhaustion, which includes nausea, vomiting, heavy sweating, and weakness,” cautions Dr Gore. He adds that the most serious is heat stroke, where the core body temperature crosses 104°F (40°C), and the person may become confused, hallucinate, or even lose consciousness. “If heat exhaustion is treated promptly, it can prevent the progression to heat stroke,” he adds

Speaking about the vulnerable groups, Dr Gore says, “These include children, the elderly, obese people, outdoor workers, athletes, and those who consume excessive alcohol. With rising temperatures, these groups are at a higher risk, even during short exposures.”

Also read | Heat stroke: Nausea, vomiting, high blood pressure are symptoms of this condition

Dr Gore suggests tips to protect yourself during heatwaves:

• Avoid outdoor activities during peak hours (11:00 am to 4:00 pm)
• Stay hydrated with water, ORS, and natural juices
• Wear light-coloured, loose-fitting clothes
• Use air conditioning at home and in vehicles if available
• Never leave pets or people in parked cars with the ac off
• Plan your day smartly to avoid exertion when temperatures peak