The urgent need to tackle heat stress effects — not just heat — this summer Premium

Rising temperatures in India pose serious health risks, urging experts to call for better heat stress monitoring and prevention measures.

A sweltering April is almost here, and temperatures across India are steadily rising this summer, a year after the hottest recorded year on Earth so far, that also saw heatwaves arrive early and for longer durations.

Heat can have a number of effects on the human body. Experts are now calling for close monitoring of the heat stress index in order to frame policies to safeguard public health.

Heat stress happens when the body cannot get rid of excess heat, causing its’s core temperature to rise, and the heart rate to increase. High temperatures combined with moisture can make it feel even hotter, as increased humidity makes it harder for the body to cool itself through sweating.

A study published in Natural Hazards by T.V. Lakshmi Kumar, who is now with Jawaharlal Nehru University, found that coastal cities in India are more vulnerable to heat stress due to climate change. Cities like Chennai, Nellore, Puducherry, and Kochi are expected to see a drop in work performance in the coming decades. People working in these cities may need longer breaks during work hours to prevent heat-related issues.

Experts note that while the India Meteorological Department defines heatwaves based on temperature, there isn’t enough focus on heat stress, which involves both temperature and humidity. For instance, the wet-bulb temperature, one of the measures that combines both the air temperature and humidity, provides an indication of heat stress on the human body.

While we usually cool down by sweating, when the wet-bulb temperature reaches a certain point, this method no longer works effectively. As a result, our body temperature continues to increase. This marks the threshold beyond which humans cannot adapt to extreme heat. If we can’t escape these conditions, our core temperature can rise to dangerous levels, potentially leading to organ failure.

Vidhya Venugopal from Sri Ramachandra Institute of Higher Education and Research, who studied occupational health risks for outdoor workers, explains that heat stress occurs when the body fails to control its internal temperature.