Related to body temperature regulation
We must know that the body constantly generates heat during metabolism to maintain body temperature, which is also transmitted to the surface of the body through blood circulation. Conduction, convection, and evaporation are continuously released to the outside world.
People with strong body resistance have normal body temperature regulation. By adjusting, the two processes of heat production and heat dissipation are balanced, that is, when the body temperature tends to decrease, the heat production increases, the heat dissipation decreases, and the body temperature is lowered. Still maintained at around 37 °C.
However, for people with weak body resistance, their ability to automatically adjust body temperature makes the body maintain normal body temperature, so when the whole body or a part of the body is cold, it is easy to catch a cold.
After we wash our hair with hot water, the scalp capillaries expand due to the warming effect, and the heat of the body to the surrounding radiation increases. At the same time, since the hair is wet after shampooing, a large amount of water evaporates. Also take a lot of heat. Generally, one gram of water is evaporated to take away 500 calories. As the heat is increased, the body is frozen, so that the upper airway capillaries are reflexively contracted, the local blood flow is reduced, and the resistance of the upper respiratory tract is reduced, so that the virus or bacteria already existing in the local area are taken in, grow and multiply, resulting in Respiratory infections, resulting in cold symptoms such as runny nose, stuffy nose, headache and even fever.
And if the baby is asleep while the hair is not dry, the adjustment function of the temperature regulation center is low, and the cold is more likely to occur.
Therefore, in general, it is best not to wash your hair before going to sleep. If you want to wash, use a dry towel to dry, then use the air tube to dry your hair before you sleep. I have a cold. I fell asleep when my hair was not dry, and I was prone to catch a cold.