Up until a decade ago, it was believed that the average person shed 100 hairs a day. As a means of measuring natural hair fall, the 60-seconds comb-through test is now preferred, with the results suggesting hair loss of just over ten hairs when combed for a minute.
Why does hair fall out?
Hair fall can occur for numerous reasons. Intense medical treatments such as chemotherapy are well known to have hair loss side effects, as well as conditions like male pattern baldness, its female equivalent androgenic alopecia, and telogen effluvium (temporary hair thinning in patches) which occurs after the body goes through a considerable shock (pregnancy, surgery, drastic weight loss etc.). Hair falling out has also been linked to vitamin imbalances (vitamins B, A and E have all been linked to hair loss), as well as protein deficiency and anaemia.
Your hair fall isn't necessarily related to medical conditions. Even simply over-styling can result in hair falling out. If you regularly tie your hair in tight hairstyles that pull on the scalp, over time you'll weaken the follicle and the hair is more likely to fall out.
The natural process of aging is the main reason people start noticing hair fall or thinning hair. While researchers are not entirely sure why this is, the theory is that the stem cells responsible for producing new hairs gradually cease production. These stem cells also dictate the change in colour as we age: when they stop producing melanin, the hair grows out grey/white and, unfortunately, there's no going back (naturally).
Hair loss and hair growth cycle
Everybody loses hair every day: it's a normal part of the hair growth cycle, which is divided into four phases.
The first is called the Anagen phase, where the hair grows on average 1.25cm per month (depending on ethnicity) for between 2-7 years.
It then moves into the Catagen phase, a short transitional phase that lasts around ten days when the follicle stops producing new hair.
The third phase, Telogen, is when the follicle rests for about four months, and is followed by the shedding of the hair itself during the Exogen phase.
If you do notice thin patches, a visible scalp or a sudden increase in hair fall, it's recommended to visit a doctor to rule out any medical concerns.