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Home > Hair Growth & Hair Types > Seasonal Variations
The normal human hair on the scalp consists of about 100,000 hair follicles. Each healthy hair follicle is capable of hair re-growth innumerable times in its lifetime. The normal rate of hair shedding is about 50-100 hairs a day, but some seasonal changes can trigger the hair shedding to occur even two times faster.
Studies are still being carried out to find out the role of seasonal changes in hair re growth. According to researchers, hair grows steadily in winter while shedding starts increasing in spring and reaches its maximum in fall to have 100 hairs shed in a day. The shedding also affects rate of hairregrowth.
The rate of seasonal hair shedding and hair re growth can vary from person to person. Some people are prone to shed large amounts of hair but they soon can have their hair growth restored through quick hair re growth with the change of season.
Reasons of seasonal changes in hair re-growth
Though the reasons for hair growth due to seasonal changes are quite ambiguous, the following facts try to infer some meaningful information from these.
The recognized reason of hair shedding is the Anagen cyclical phase. In summer 90% of hair on the scalp is in the anagen phase. While in September soemwhat fewer follicles remain in the growing (anagen) phase. The ratio of hair in the telogen (resting) phase increases to about 10 or 20% more when compared to the summer time.
Researchers had observed that the plasma testosterone in European males fluctuates seasonally. Testosterone is an essential hormone which is regulates hair re-growth on the scalp. Imbalance in the level of hormones leads to pattern baldness in men and women. Besides pattern baldness, hormonal imbalance causes even thinning of hair in the over all scalp of a woman.
So the researchers are of the view that an imbalance in the level of testosterone may also be the major cause of seasonal hair re growth variations. It is also observed that the diameter of the growing hair remained unaffected during these seasonal fluctuations.
Exposure to daylight
Experimental studies suggest reducing exposure to daylight may prevent seasonal hair shedding. It has been observed that minimal exposure to daylight hours modifies the melatonin secretion rate from the pineal gland, and this in turn affects hormones and their receptors that are present in the skin of the scalp. Since hormone receptors play a major role in hair loss, exposure to day light has some role to play in hair shedding.
A fluctuation in hair growth or shedding due to seasonal variations is a normal process. The seasonal changes in hairregrowth or shedding are replaced as soon as there is a change in the season. This temporary hair loss is evident in every human being and it not only affects the scalp hair growth but also hair growth on the thighs, beard etc.
Though the seasonal variation is not of much concern from the point of view of the pathology of hair loss, relating it to the structure and function just provides better insight for understanding the hair loss.
Understand the biology of hair follicle, physiology of hair re-growth and the hair loss causes and try them to relate to your condition of hair loss, and help your self to take good care of your hair.