India is experiencing a temperature of nearly 50 degrees, and even mosquitoes have disappeared! What will happen to people?

Recently, "India has seen a temperature of nearly 50 degrees Celsius, and even mosquitoes have disappeared" has become a hot search topic. The news pointed out that the temperature at the Indian monitoring station reached a maximum of 49.1 degrees Celsius, which is close to the limit of human survival, and even mosquitoes can't stand it.

Image source: Sina Weibo

What does a high temperature of 50℃ mean? What effects will it have on the human body? Let’s talk about it in detail today.

50℃ high temperature,

What does it mean?

Have you ever walked barefoot on the road in the summer sun?

Anyone who has tried it will understand the burning sensation. Its temperature is about 50 degrees Celsius or even higher. Such a temperature will not only cause pain and discomfort, but may also cause burns or scalds on the soles of the feet.

Have you ever been to a steam room?

After entering the steam room, people will immediately be surrounded by warm and humid air, and then every pore in the body seems to be opened instantly, and sweat will come out.

As time goes by, sweat will pour down from the forehead, nose and back like a waterfall, and people will gradually be engulfed by the heat wave, which makes it difficult to breathe, and even start to feel uncomfortable and dizzy. The temperature of a general steam room is about 40-50°C.

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High temperature to human body

What impact will it have?

The impact of ambient temperature on the human body is huge, and we feel very different at different temperatures.

The most suitable environmental temperature range for the human body is 20-25℃. At this time, the human body feels comfortable and the metabolic function is stable. It does not need extra energy to keep warm, nor does it need to dissipate heat through excessive sweating.

As the temperature gradually rises, it enters the body's thermal neutral zone. At this time, the body will dissipate heat through a series of physiological adjustments and behavioral changes to maintain a stable core body temperature:

Sweating: Increased activity of sweat glands produces sweat, which removes heat through evaporation, an effective heat dissipation mechanism.

Vascular dilation: The blood vessels of the skin dilate (vasodilation), increasing blood flow to the skin and thereby increasing heat loss through radiation, conduction, and convection.

Breathing faster: By increasing your breathing rate, you increase the amount of heat lost through exhaled air and evaporation of water from the walls of your respiratory tract.

Behavioral modifications: People may take actions to help dissipate heat, such as reducing activity, seeking shade, removing excess clothing, or increasing ventilation.

Metabolic rate changes: In some cases, metabolic rate may increase slightly, but this is usually not related to thermoregulation but may be related to increased cardiovascular and respiratory workload.

Evaporative cooling: Increased heat loss through evaporation of water from the skin and respiratory tract.

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People who spend long periods of time in warm or hot environments may develop heat acclimatization, a process that alters physiological and behavioral responses to improve adaptability and effectiveness in hot environments.

There is currently no consensus on the upper limit of the thermoneutral zone, and the highest value in the research data is 40-50°C.

If the temperature exceeds 50℃, people will feel like they are in a scorching oven, surrounded by scorching heat waves, and every breath is as hot as inhaling flames.

At the same time, sweat pours out from all parts of the body like a fountain, clothes stick to the body, sticky and not breathable, the burden on the human body is significantly increased, and heat stress, confusion, nausea, dizziness, headache and fainting occur. Studies show:

Compared to an environment with a temperature of 28°C and an air humidity of 50%, participants in the 50°C and 50% air humidity conditions sweated 74% more, their heart rate increased 64%, and their myocardial workload increased, which means their hearts needed more oxygen to maintain optimal function.

Respiratory rate also increased by 23%, the amount of air inhaled and exhaled per minute increased by 78%, and drinking water did not lower body temperature.

In this case, people are very likely to suffer from heat stroke, and in severe cases, they may die.

In addition, prolonged exposure to high temperatures of 50°C may also cause skin burns, breathing difficulties and other related health problems.

In short, with the continued impact of global climate change, high temperature extreme weather is no longer a rare phenomenon. Facing such a high temperature of 50℃, we must realize that it has a huge impact on our health. We must pay attention to high temperatures and take precautions.

References

[1] The difference between the weather forecast temperature and the actual ground temperature is 30°C? Here is the official answer: http://gaj.ningbo.gov.cn/art/2022/8/8/art_1229027022_58924139.html

[2] Koop LK, Tadi P. Physiology, Heat Loss. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541107/

[3] Pallubinsky H, Schellen L, van Marken Lichtenbelt WD. Exploring the human thermoneutral zone - A dynamic approach. J Therm Biol. 2019 Jan;79:199-208.

[4] Henderson MET, Halsey LG. The metabolic upper critical temperature of the human thermoneutral zone. J Therm Biol. 2022; 110:103380.

[5] Henderson MET, Brayson D, Halsey LG. The cardio-respiratory effects of passive heating and the human thermoneutral zone. Physiol Rep. 2021 Aug;9(16):e14973.

[6] Gonzalez-Rivas PA, Chauhan SS, Ha M, et al. Effects of heat stress on animal physiology, metabolism, and meat quality: A review. Meat Sci. 2020;162:108025.

Author: Jiang Yongyuan, Internal Medicine Doctor

Reviewer: Wang Qian, Chief Physician of the Emergency Department, the Third Medical Center, PLA General Hospital