Theoretically, with hot shower, the skin pores open while cold shower closes them. It is good to close your pores to prevent the pores from being easily clogged by dirt and oil. Aside from this, cold shower is great for blood circulation
, stimulates the nervous system and said to make the hair look healthier and shinier. It closes the hair cuticle which makes the hair stronger and also prevents dirt from easily accumulating within the scalp.