The normal cycle of hair growing lasts for 2 to 3 years. Each hair grows around 1 centimeter per month through this phase. About 90 percent of the hair on your scalp is rising at any one time. About 10 percent of the hair on your scalp, at any one time, is in a resting phase. After 3 to 4 months, the sleeping hair falls out and new hair starts to grow in its place.
It is normal to shed some hair each day as part of this cycle. However, some people may experience extreme hair loss. Hair loss of this type can affect men, women and children.