India´s record temperature was a sensor error. It was only 49,1C which is bad enough...
https://www.nu.nl/buitenland/6315160/indiase-recordtemperatuur-ontstond-door-storing-niet-529-maar-491-graden.htmlHeat kills at least 15 in India as temperatures near 50C
https://www.bbc.com/news/articles/czddy30ezd5oThe human body has a very narrow range of temperature it finds ideal. It works best when the temperature is between 36C to 37.5C, or 96.8F to 99.5F. Anything over this is dangerous.
Ambient air temperature of 18-24C is good for most people, although people who are healthy and more well adapted to heat can sustain slightly higher temperatures.
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For most people but especially the vulnerable, prolonged exposure to temperatures above 40C causes heat stress as the body starts to struggle to cool itself down.
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When the temperature rises above 46C, cells, the tiny building blocks of our body, start getting damaged or destroyed.
The body’s inability to regulate its temperature can also worsen existing chronic conditions like cardiovascular, respiratory and cerebrovascular diseases and ailments related to diabetes, according to the National Institute of Environmental Health Science in the US.
A recent analysis suggested that increasing heat can also worsen certain brain conditions.
Role of humidity
Air temperature alone doesn’t tell the full story. Humidity is an important factor in how we feel the heat, especially when it is as hot as 50C.
High humidity prevents the body from cooling itself by sweating, raising the risk of heatstroke and other potentially fatal conditions.
Humidity in the air is measured as “wet bulb temperature”, so named as it is measured by wrapping a wet cloth around a thermometer and seeing how much cooler it gets.
A wet bulb temperature of 32C is usually the maximum a human body can endure. This is equivalent to a dry temperature of 55C. The theoretical maximum wet bulb temperature is 35C, which means most humans are likely to suffer heatstroke at this level.
When air temperature is 46.1C and relative humidity is 30 per cent, the wet bulb temperature is 30.5C. But when air temperature is 38.9C and relative humidity is 77 per cent, the wet bulb temperature is about 35C.
Heat in India, as in much of South Asia, is extremely humid. The average relative humidity of Delhi is 67 per cent, which makes higher temperatures particularly dangerous.
Studies have shown that when air temperature reaches 35C and is accompanied by high humidity, it becomes risky for our health. Once 40C is reached, the heat can be dangerous even with low humidity levels.
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Night temperatures
It’s not just daytime heat that is scorching South Asia. Night temperatures have been as high as 36C in some places in northern India, which is particularly dangerous since it means people cannot cool off at night to fall asleep.
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https://www.independent.co.uk/climate-change/news/india-temperature-weather-heat-stroke-human-body-b2554016.html
