The rhythm of modern people’s life is relatively tight. Work, activities, entertainment, etc. are not busy during the day. It is rare to be able to wash your hair comfortably at night.
After shampooing at night, if you have enough time to let your hair dry before sleeping, then of course it is best. But sometimes it was too busy. I washed my hair after 10 o’clock in the evening. After washing my hair, I was so tired that my eyelids were too heavy to open, so I fell asleep before the hair was dry. In doing so, the older generation will say that they will have headaches in the future. In fact, after research in modern science, people find that this is not unreasonable.
We must know that during the metabolic process of the human body, heat is constantly generated to maintain body temperature. This heat is also transferred to the surface of the body through blood circulation and is continuously released to the outside world through radiation, conduction, convection, and evaporation.
For people with strong body resistance, the body temperature regulation function is normal, and the two processes of heat generation and heat dissipation are balanced through adjustment. That is, when the body temperature tends to decrease, the heat production increases, and the heat dissipation decreases, so the body temperature is still maintained at about 37 ℃.
However, for people with weak body resistance, their ability to automatically adjust body temperature to maintain the body’s normal body temperature is poor, so it is easy to catch a cold when the whole body or a certain part is cold. After we wash our hair with hot water, due to the warming effect, the scalp capillaries expand, and the body radiates heat to the surroundings. At the same time, because the hair is wet after shampooing, a lot of water evaporates out, and it also takes a lot of heat. Generally, one gram of water takes 500 calories when it evaporates.
Due to the increased heat dissipation, the body is frozen, so the capillaries of the upper respiratory tract are reflexively contracted, the local blood flow is reduced, and the resistance of the upper respiratory tract is reduced. Respiratory tract infections, result in cold symptoms, such as runny nose, stuffy nose, headache, and even fever.
If you fall asleep when your hair is not dry, at this time the adjustment function of the temperature regulation center is low, and it is more likely to cause a cold.
Therefore, in general, it is best not to wash your hair before going to bed. If you want to wash it, dry it with a dry towel, and then use a hairdryer to dry your hair before going to sleep, so that you will not catch a cold.
Falling asleep with your hair dry, you may catch a cold easily.
