Why do people feel hot at 37℃ and cold when taking a bath?

In summer, it is hot and dry. If you are outdoors at 37℃, you will sweat for a few minutes. But when we take a bath, even in hot summer, the water temperature of 37℃ will feel cool. It's obviously 37℃. Why do we feel different?

We know that people are warm-blooded animals, and the core temperature is around 37℃, which is the temperature inside the human body, not the surface temperature. The surface temperature of the human body is about 33.5 degrees Celsius lower than the internal temperature. When the temperature reaches 37℃, the difference between the human body surface temperature and the air temperature will be reduced, the cooling rate of blood breathing will be slowed down, and the brain will be stimulated, resulting in a sweating sequence. At this time, we will feel hot

What about when we were in the water? The heat transfer capacity of water is 25 times that of air, and the heat loss rate of water body is 25 times that of air. If the heat dissipates quickly, you won't feel it naturally. Flowing water will accelerate the transfer of temperature. The temperature in the air will also decrease accordingly. Just like when we are hot, we put water on the ground. So it will feel a little cold if you wash it.

Generally speaking, the most comfortable temperature of human body is between17 and 24℃, and the most suitable temperature is between 36 and 42℃. I don't feel hot or cold. The human body temperature of 37 degrees refers to the temperature in the human body. The rectal temperature is closest to the body temperature that can be directly measured. But in any case, the body surface temperature is lower than the body temperature. When the ambient air temperature is higher than 35℃, it is generally higher than the skin surface temperature, resulting in poor evaporation of water on the skin surface, and the heat generated in the body is not suitable for discharge, so it is necessary to "feel" the heat. In short, if the heat of the skin is not suitable for loss, it is "feeling" to be hot, and if the heat of the skin loses quickly, it is "feeling" to be cold (you can feel it by applying a small amount of alcohol or high-concentration white wine to the skin). There is no absolute relationship with the external environment temperature.