It’s been unbearable hot for days now, so I’ll keep this nice and cool. What in the living hell is the highest temperature the human body can endure?
NASA has spoken and found that June 2023 was the hottest June on record. According to its global temperature analysis, European Union’s Copernicus Climate Change Service and NOAA’s National Centers for Environmental Information June 2023 is by far the warmest in their records.
The answer is scientifically straightforward: a wet-bulb temperature of between 34 C to 36.5 C degrees (rounded at 35 C), according to a 2020 study published in the journal Science Advances.
And WHAT is wet-bulb temperature? It’s not a “regular outside” temperature — it is measured by a thermometer covered in a water-soaked cloth, so it takes into account both heat and humidity.
As one may already know, the higher the humidity (more water in the air), it’s harder for our natural cooling mechanism — sweat — to evaporate off the body and cool us down.
But, even if the wet-bulb temperature is high with low humidity or vice versa, the wet-bulb temperature probably won’t be near the human body’s tipping point, said Colin Raymond, a postdoctoral researcher at NASA’s Jet Propulsion Laboratory who studies extreme heat.
But when both the humidity *and* the temperature are very high, the wet-bulb temperature can go to dangerous levels.
Raymond gives Live Science an example: when the air temperature is 46.1 C and the relative humidity is 30%, the wet-bulb temperature is about 30.5 C.
But when the air temperature is 38.9 C and the relative humidity is 77%, the wet-bulb temperature is about 35C.
The reason humans can’t survive in high heat and high humidity is that we can’t keep up with regulating our internal temperature.
If the wet-bulb temperature rises above the human body temperature, you can still sweat, but you’re not going to be able to cool your body to the temperature that it needs to operate at physiologically.
At this point, the body becomes hyperthermic — above 40 C. This can lead to rapid pulse and arrhythmia, a change in mental status and cognition, a lack of sweating, faintness, and coma, according to the National Institutes of Health.
A wet-bulb temperature of 35C won’t cause immediate death, however, it would probably take about 3 hours (even though there’s no way to know the exact time) for that heat to be unsurvivable.
The studies have tried to estimate the time we can adequately function in high temperatures by immersing human participants in hot water tanks and removing them when their body temperatures began to rise uncontrollably.
Although no one can live at a wet-bulb temperature higher than about 35 C, there are a lot of other reasons people die in slightly lower temperatures than that.
Exercise and exposure to direct sunlight make it easier to overheat. Older people; people with certain health conditions, such as obesity; and people who take antipsychotics can’t regulate their temperature as well, so it’s easier for heat to literally kill them.
Luckily, there’s air conditioning, for all of us privileged souls.
Few locations have hit a wet-bulb temperature of 35C in recorded history, according to the above-mentioned Science Advances study.
Since the late 1980s and 1990s, hotspots have been the Indus River Valley of central and northern Pakistan and the southern shore of the Persian Gulf.
Locations that are at risk of extreme temperatures in the next 30 to 50 years include northwest Mexico, northern India, Southeast Asia, and West Africa.
With global warming, the list of regions with deadly temperatures will continue to get bigger.
No pressure, but brace yourselves and hydrate regularly (check the color of your urine iykyk) in the coming days, months, and years.