June 2

If the human body temperature is 37 degrees, why does a 37 degree summer day still make us feel so hot?


The metabolism in our body always generates heat equivalent to a 400 watt machine.

In the summer, temperatures reaching 37 degrees Celsius can make you cry out because of the heat. But on the contrary, have you ever seen God calling you when your body temperature is always at 37 degrees Celsius?

Unless the number goes up by 3 degrees. You will be at risk of going to heaven if your body temperature rises to 40 degrees Celsius without being able to lower it. The truth is that only a few elite athletes in the world (such as those participating in the Tour de France) can survive in these 40 degrees.

But going back to the 37 of the average person: When our body temperature and the temperature outside are equal, why do you still feel extremely hot and uncomfortable?

We are warm-blooded creatures, not lizards

Based on the characteristics of body temperature, animals are divided into 2 groups: Cold-blooded or thermogenic animals (such as fish, lizards, amphibians such as frogs and most invertebrates) body temperature varies significantly according to the external environment.

And the second group is warm-blooded animals, or endothermic, endothermic animals (like birds and mammals) that are able to maintain their body temperature at a constant threshold, regardless of the ambient temperature.

As you know, we humans belong to the second group.

To be able to maintain a body temperature of 37 degrees Celsius at all times, our body must constantly heat itself through metabolism. You can think of every cell in your body like a small chemical reactor. And they run 24/7, constantly generating heat, no matter what you’re doing, sitting around, taking a walk, doing intense exercise, or reading this article on your phone.

Even when you sleep, your brain cells are still active and your body is still metabolic, digesting food, breathing and circulating blood. All these ongoing processes still generate heat. The maximum temperature range that your body can lower by reducing metabolic processes is 1 degree Celsius. That is, when you sleep, your body’s lowest body temperature is still 36 degrees.

If somehow your body temperature drops below 35 degrees Celsius, a medical condition known as hypothermia will occur. It prevents your heart, nervous system, and other organs from working properly. If left untreated, hypothermia can lead to heart failure and respiratory failure, eventually leading to death.

A word of caution is that you can completely hypothermia while sleeping with air conditioning. I once lay on top of the air conditioner control while I was sleeping and the room temperature suddenly dropped to 16 degrees Celsius.

Fortunately, the human body always has unconscious defense mechanisms, when your body temperature drops too much, your first reaction will be to pull a blanket or anything that can warm you. But even if a thin summer blanket can’t keep you warm any longer, it will wake you up.

Your metabolism is boosted, your muscles convulsing and shivering continuously to generate heat. Or simply your brain needs to figure out how to get out of that cold environment.

We are not lizards that can casually bask in the midday sun or endure the cold at night in the swamp. I knew the only way to help me survive and get back to sleep was to find the AC control and turn it back up to 24 degrees.

Why does the outdoor temperature of 37 degrees Celsius still make us uncomfortable?

You should now be able to reason a bit to answer this question. When we say our body temperature is 37 degrees Celsius in the summer, we are actually running the cooler continuously to maintain that temperature threshold.

The metabolism in our body always generates heat equivalent to a 400 watt machine. And if not cooled in time, your body temperature will sooner or later rise a few degrees to the point of death.

To cool down, the body uses 4 main machines:

  1. Heat conduction: When you actually transfer your excess heat to a cooler object through contact (eg holding a glass of iced tea). The amount of heat transferred through conduction is only about 2% of the body temperature you want to cool down, so it’s negligible.
  2. Convection: The convection cooling mechanism accounts for a higher proportion, about 10%. That’s when you transfer heat directly to air or water, this stream of air and water is then blown or pushed away from you, replacing it with a stream of cooler air or water. Turn on the fan when it’s hot and take a cold shower, you’re cooling down by convection.
  3. Evaporation: About 35% of the heat lost from your body comes from evaporation. That’s when your body sweats, transferring heat to sweat so that when the sweat evaporates, they also carry your excess body heat away from your body.
  4. Radiation: This is the most effective heat dissipation mechanism, when radiation will transfer heat from a hot object to a colder environment. This amount of heat can account for about 65% of your total body heat loss.

Unfortunately, in the summer, when the ambient temperature rises to 37 degrees Celsius, it suppresses the most powerful cooling machine from radiation. When the outside temperature is the same as your body temperature, the body can no longer transfer heat to the outside.

Cooling machine number 4 is completely turned off, causing machine number 3 to work to increase capacity. You will have to sweat more to be able to cool down to 37 degrees (Please pay attention to drink more water to be able to maintain this cooling machine).

Either you will have to go into the air-conditioned room to restart the No. 4 cooler, or turn on the fan, take a shower to start up the No. 2 cooler. The No. 1 cooler basically doesn’t help much.

So a disabled cooling machine, causing a cooler to operate at increased capacity is the simple reason why you feel uncomfortable, even when the outdoor temperature is equal to your body temperature. friend.

A heat tip: It’s your body will feel most comfortable when the working speed of the 4th machine is equal to the body’s heat production rate. Then, you won’t have to start up the number 3 engine, which makes you sweat to cool down.

Studies show that the optimal heat difference for radiation from the body with its metabolic activity is between 13-19 degrees. That means the ambient temperature that the body is most comfortable with is between 18-24 degrees Celsius. Remember these two numbers to adjust the air conditioner this summer.


air conditioning, body temperature, hypothermia, summer, temperature, umd

You may also like

What if we spread solar cells to fill the Sahara?

Get in touch

0 of 350