Heat stroke vs heat exhaustion: Understanding the more dangerous summer threat

As large parts of India continue to reel under an intense heatwave, health experts are warning.

That prolonged exposure to extreme temperatures can quickly become dangerous if early warning signs are ignored. With temperatures crossing 45°C in several regions, the India Meteorological Department (IMD) has repeatedly cautioned people about severe heatwave conditions across north, central and eastern India.

Cities and states including Delhi, Rajasthan, Haryana, Punjab, Uttar Pradesh, Madhya Pradesh and Vidarbha have witnessed soaring temperatures, raising concerns over dehydration, heat exhaustion and heat stroke cases. Medical professionals say many people fail to recognise the difference between heat exhaustion and heat stroke — a distinction that can prove life-saving during extreme summer conditions.

WHAT EXTREME HEAT DOES TO THE BODY

The human body naturally regulates temperature through sweating. However, during prolonged exposure to excessive heat, especially when humidity is high, the body can struggle to cool itself effectively. This can lead to dehydration, electrolyte imbalance, reduced blood circulation and added stress on vital organs.

According to public health expert Dr. Sameer Bhati, even mild dehydration can begin affecting the body before obvious symptoms appear.

“Fatigue, dizziness, dry mouth and reduced urination are often early indicators that people ignore. If dehydration worsens, it can impact circulation and organ function significantly,” he explained.

Doctors say the body loses both water and essential salts through sweating, making hydration critical during heatwave conditions.

HEAT EXHAUSTION VS HEAT STROKE

Heat exhaustion is considered an early warning stage that develops when the body loses excessive fluids and salt. While serious, it can usually be reversed quickly if treated in time.

Common symptoms include:

• Excessive sweating
• Weakness and fatigue
• Headache
• Dizziness or fainting
• Nausea or vomiting
• Cool or clammy skin

Body temperature that remains below dangerous levels
If left untreated, heat exhaustion can progress into heat stroke — a medical emergency where the body loses the ability to regulate temperature.

Heat stroke symptoms include:

• Body temperature above 104°F (40°C)
• Hot and dry skin
• Confusion or slurred speech
• Rapid heartbeat
• Seizures
• Loss of consciousness

Doctors warn that heat stroke can lead to organ failure or death if emergency treatment is delayed.

WHEN IS IT MOST DANGEROUS TO GO OUTSIDE?

Health advisories recommend avoiding direct sun exposure between 12 PM and 4 PM, when temperatures peak and the risk of heat-related illness rises sharply. Some experts advise limiting outdoor activity even earlier, between 11 AM and 4 PM, especially for children, elderly people and those with medical conditions.

People working outdoors are encouraged to take frequent breaks, remain hydrated and monitor for early symptoms such as dizziness or unusual fatigue.

HOW TO RESPOND DURING A HEAT EMERGENCY

For heat exhaustion:

• Move the person to a cool or shaded area
• Loosen or remove excess clothing
• Apply cool cloths or fan the body
• Give cool water or oral rehydration fluids
• Allow the person to rest and elevate their legs
• Seek medical attention if symptoms persist

For suspected heat stroke:

Call emergency medical services immediately
Move the person out of direct sunlight
Cool the body rapidly with cold water, ice packs or wet cloths
Place ice packs around the neck, armpits and groin
Avoid giving fluids if the person is unconscious or confused

HOW TO STAY SAFE DURING HEATWAVES

Experts recommend simple but effective precautions during extreme summer conditions:

• Drink water regularly, even if you are not thirsty
• Consume electrolyte-rich fluids such as coconut water or buttermilk
• Wear loose, light-coloured cotton clothing
• Use hats, umbrellas and sunglasses outdoors
• Avoid strenuous activities during peak heat hours
• Keep homes well-ventilated and cool
• Never leave children, elderly people or pets inside parked vehicles

As heatwaves become more frequent and intense across India, health experts stress that awareness and early action remain the best defence against potentially life-threatening heat-related illnesses.