Normal healthy people lose 50-150 hairs each day usually seen in the comb, brush, sink or pillow. This is a result of the normal hair cycle. Hair grows for several years, rests for several months, sheds and re-grows. Telogen is the name of the resting stage of the normal hair growth cycle.
In a normal person, the majority of the hair follicles are actively growing while only about 15% are in the resting state. When hairs are in this resting or telogen state, they will shed or fall out. If there is a stress to the body such as a physical or emotional trauma, as many as 70% of the scalp hair roots are pushed prematurely into the resting state causing a sudden increase in hair loss; this is known as telogen effluvium.