India braces for 45°C heatwave in 2 days: What extreme heat does to your health

A strong heatwave is set to sweep across large parts of India over the next few days, with temperatures expected to rise sharply.

According to the India Meteorological Department, heatwave conditions will affect central and eastern regions from mid-April. Cities like Nagpur, Bhopal, Amravati and Bhubaneswar could see temperatures between 42 degrees Celsius and 45 degrees Celsius.

Delhi-NCR is also likely to cross 40 degrees Celsius for the first time this season, while parts of Uttar Pradesh and Rajasthan may touch 42-43 degrees Celsius.

WHAT HAPPENS TO YOUR BODY IN EXTREME HEAT

As temperatures rise, the human body comes under stress. Research from the University of Roehampton shows that once temperatures cross 35 degrees Celsius, breathing becomes faster and heart rate increases.

At around 40 degrees Celsius, the body works much harder to stay cool, increasing its energy use by nearly 35%. While core body temperature remains stable for a while, prolonged exposure can be dangerous.

Studies suggest that temperatures beyond 42 degrees Celsius can cause serious harm, including damage to the brain if exposure is prolonged.

HEAT CAN TRIGGER SERIOUS ILLNESSES

Doctors warn that heat can lead to a range of health problems. "From heat rash and cramps to severe dehydration and heatstroke, especially in people with conditions like diabetes or kidney disease that can happen during excessive heat,” Dr. Niveditha Alok Swamy, Consultant, Internal Medicine, SPARSH Hospital, told indiatoday.tech.

Heat exhaustion can cause heavy sweating, weakness, nausea and cramps.

If it worsens into heatstroke, when body temperature crosses 40°C, it can lead to confusion, seizures and even organ failure, requiring urgent medical care.

Excessive sweating can also cause dehydration and loss of essential salts, increasing the risk of dizziness and fainting.

Extreme heat can also quietly disrupt how your digestive system works. When temperatures rise, the body’s top priority is to stay cool. To do this, it sends more blood to the skin to help release heat through sweating.

This shift means less blood flows to the digestive system, slowing down digestion. As a result, people may experience a feeling of heaviness in the stomach, reduced appetite, acid reflux, or general indigestion.

Dehydration makes this worse. When the body lacks enough fluids, digestion becomes even slower, leading to issues like constipation and abdominal cramps. These symptoms are especially common among older adults and those who are not drinking enough water during hot weather.

IMPACT ON MENTAL HEALTH

High temperatures don’t just affect the body, they can also impact mental health.

Dr. Rahul Ratan Bagale, Consultant Psychiatrist, Apollo Clinic, Viman Nagar, said extreme heat can lead to sleep problems, irritability and difficulty concentrating.

“Prolonged exposure can also increase anxiety and depression, as people feel trapped indoors or unable to cope with the heat,” he said.

Studies have also linked hot days to higher hospital visits for mood disorders and other mental health conditions.

HOW TO STAY SAFE

According to WHO guidelines:

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1. Open windows at night, and close them during the day. Use blinds or curtains to block sunlight.
2. Turn off electrical devices to reduce indoor heat.
3. Use fans and AC wisely: Fans work best when temperatures are below 40C. Air conditioning should be set at 27C; using a fan alongside can make it feel 4C cooler and cut electricity usage by up to 70%.
4. Drink 2–3 litres of water daily. Avoid alcohol and caffeine which dehydrate the body. Include more fruits and vegetables in your diet.
5. Carry a bottle of ORS when stepping out in the heat. Make sure to rehydrate the body every 2 hours.
6. Wear light-coloured, loose-fitting clothes.
7. Regularly monitor children, the elderly, and those with chronic conditions.

As heatwaves become more frequent due to climate change, the need for awareness and early action is needed.