The critical limit is lower than expected.
Scientists from the University of Pennsylvania decided to find out what is the maximum heat the human body can withstand without reducing normal daily activity. The result showed that the critical characteristic is lower than previously predicted, reports Science Alert.
Scientists note that the heat indicators go far beyond the numbers on the thermometer. The level of humidity is also important. And the combination of these two factors may be much more dangerous than previously thought. The impact of heat on the human body and the upper limit that it can withstand are of interest to scientists as average global temperatures increase and the frequency of combinations of high temperatures and humidity, which is called “wet bulb temperature”, increases.
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According to the authors of the paper, people often refer to a 2010 study that showed that a temperature of 35 degrees Celsius with 100% humidity and 46 degrees at 50% humidity is the limit beyond which the human body is no longer able to cool itself by evaporating sweat, maintaining a stable internal temperature
But recently this limit has been tested on humans in laboratory conditions. And the results of such testing showed an even more frightening result.
Young and healthy men and women participated in the experiment. Each of the volunteers swallowed a small telemetry pill that measured their internal body temperature. After that, they were placed in a climatic chamber, where they moved just enough to simulate the daily activities of a person: cooking or eating. Scientists slowly increased the temperature and then the humidity in the room, monitoring when the internal temperature of the body begins to rise.
The combination of temperature and humidity, at which the internal temperature of the human body increases, is called the “critical limit of the environment” . Below this limit, the body is able to maintain a relatively stable internal temperature, when it is exceeded, the temperature constantly rises, and with it the risks of developing heat-related diseases.
When the body overheats, the heart has to work faster to pump blood to the skin, and sweating reduces body fluid. In the most severe case, prolonged exposure to heat can lead to heat stroke, which requires immediate cooling of the body and treatment.
The experiment showed that the critical limit of the environment lies below 35 degrees Celsius. In fact, at 100% humidity, the critical temperature is 31 degrees Celsius, and at 60% – 38 degrees Celsius.
Scientists note that the current heat waves reach or even exceed the temperature values. But such a temperature is critical at high humidity. In dry conditions, sweat evaporates, allowing the body to cool itself. But the amount of sweat that can be produced by the body is limited.
In addition, the researchers note that the indicated temperatures are critical, but even lower temperatures and humidity can cause excessive strain on the heart and other body systems.< /p>
In the future, researchers want to test the effect of temperature and humidity on the elderly, since 80-90% of the victims of abnormal heat are on people over 65.
Scientists also emphasize that in the heat, especially it is important to drink enough liquid and find places where you can cool down at least for a short time.
Important! This publication is based on the latest and current scientific research in the field of medicine and has an exclusively general informational character. The publication cannot be the basis for establishing any diagnoses. If you are sick or need a diagnosis, see a doctor!
