There are countless sweat glands and sebaceous glands on the scalp, and they often secrete sweat and grease and covered by your hair. It is also difficult for heat to dissipate, secretion will merge easily with dust and dandruff, thus will cause the growth of bacteria , damaging hair follicles and hair quality. The long-term exposure of hair to air, will result in bacteria within the air to come into contact with secretions from the sebaceous glands of the head, creating dandruff and dirt in the process. Therefore, you have to comb and wash your hair regularly, for it to stay healthy, shiny and elastic (people with oily scalp should wash their hair every day and those with very little oil generated on their scalp are to wash their hair 2 to 3 times a week at least).
It is most appropriate to wash your hair with lukewarm water. If the water temperature is too low, it would be difficult to remove grease; if the temperature is too high, it will also damage your scalp, worsening the dandruff problem. Most people with hair loss who use either hot water or cold water to wash their hair, it is a kind negative stimulus for both hair and scalp, worsening the problem of hair loss. After washing the hair, it is best to let it dry naturally.