Heatwaves are making nights warmer than ever: Why it's dangerous for our health

India Today

22-05-2025

A new study has revealed that nearly 76% of India's population is now living in districts marked as "high" or "very high" heat risk zones.The report, released by Delhi-based think tank Council on Energy, Environment and Water (CEEW), highlights the increasing danger caused by extreme heat and humidity across the country.The study, which assessed 734 districts using 40 years of climate data (1982–2022), found that 417 districts, which is more than half of India, are under high to very high heat risk.advertisement
These include major states and union territories like Delhi, Maharashtra, Goa, Kerala, Gujarat, Rajasthan, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, and Uttar Pradesh.NIGHTS BECOMING HOTTER THAN DAYSWhile daytime temperatures continue to rise, the report also found that very warm nights, when minimum temperatures exceed the 95th percentile of historical norms, are increasing even faster than very hot days.This has serious implications for health.
While daytime temperatures continue to rise, the report also found that very warm nights, when minimum temperaturesexceed the 95th percentile of historical norms, are increasing even faster than very hot days. (Photo: Reuters)
High night temperatures can be more dangerous because the body doesn't get a chance to cool down after daytime heat exposure.advertisement"The rise in very warm nights is most noticeable in districts with a large population," the study noted, citing cities like Mumbai, Bengaluru, Bhopal, Jaipur, Delhi, and Chennai, where summer nights have become significantly hotter over the past decade.IMPACT OF HEAT ON HEALTHDoctors have warned that prolonged exposure to high heat and humidity is taking a visible toll on people's health."We are seeing a spike in cases of persistent headaches, dizziness, fatigue, muscle cramps, dehydration, and poor sleep quality," said Dr. Arunesh Kumar, Senior Consultant, Respiratory Medicine, Paras Health, Gurugram.People with chronic conditions like asthma are particularly vulnerable, since the heavy, moisture-laden air can worsen respiratory discomfort.
Doctors have warned that prolonged exposure to high heat and humidity is taking a visible toll on people's health. ()
High humidity also interferes with the body's natural cooling mechanism by limiting the evaporation of sweat, which leads to overheating and increases the risk of heat exhaustion or even heatstroke.The CEEW study further found that summer humidity in northern parts of the country has climbed from 30-40% to 40-50% in the last decade, making early mornings feel warmer and worsening heat stress, especially for outdoor workers in the Indo-Gangetic plain.advertisementRECORD-BREAKING TEMPERATURES AND EARLY HEATWAVESThe year 2024 was the hottest on record in India and worldwide, and 2025 isn't far behind.The country experienced its first heatwave this year as early as February 27–28, more than a month earlier than the previous year.According to the World Health Organisation, over 1.66 lakh people died globally due to heatwaves between 1998 and 2017.
According to the World Health Organisation, over 1.66 lakh people died globally due to heatwaves between 1998 and 2017. ()
In India alone, over 48,000 heatstroke cases and 159 deaths were reported in 2023, although experts believe the actual numbers are likely higher.HEATSTROKE HAS LONG-TERM EFFECTSHeatstroke is often viewed through a narrow lens: a medical emergency requiring quick hydration and cooling.But this dangerous condition doesn't end when the fever breaks or the pulse stabilises, according to Dr. Vikram Vora, Medical Director, International SOS.advertisement"What it leaves behind, both mentally and physically, can quietly compromise an individual's ability to work, focus, and live well," Dr. Vora told IndiaToday.In.Dr. Vora added that many survivors suffer from fatigue, chronic dehydration, muscle cramps, and even cognitive issues like memory loss or difficulty concentrating.This has major implications for workers in both outdoor and indoor settings.
Heatstroke is often viewed through a narrow lens: a medical emergency requiring quick hydration and cooling. (Photo: PTI)
"Over time, the psychological strain of working in relentless heat, or the trauma of having experienced heatstroke, can lead to chronic anxiety, irritability, and depression. Workers report feelings of dread before each shift, knowing what's in store," he said.He recommended that employers invest in shaded break zones, water stations, and restrooms, and include heat-exposed workers in mental health and wellness programs.HOW TO STAY SAFE FROM HEATSTROKEAs temperatures soar, the risk of heatstroke also increases.Dr RS Mishra, principal director, internal medicine at Fortis Hospital, outlined key strategies to prevent heat-related illnesses:advertisementStay hydrated with water and electrolyte-rich drinks.Wear light, breathable clothing and use accessories like hats and sunglasses.Avoid outdoor activity during peak sun hours (10 am – 4 pm).Take frequent breaks if working outside, and stay in the shade.Know the symptoms of heatstroke, like dizziness, cramps, and confusion, and seek immediate help if they occur.Use cooling methods such as fans, cold showers, or wet clothes on pulse points.Eat light, water-rich foods and monitor at-risk groups like the elderly and children.As India battles growing heat stress, both individuals and policymakers will need to take urgent action to adapt and protect public health.