How sunlight can be harmful for your hair? : Dr.Shivani Pandey

Yes, of course and that too because of the UV components of sunlight. The midday sunlight which reaches the earth surface comprises of approximately 95% with UVA radiation while, 5% with UVB radiation.

UVC and the majority of UVB are absorbed by ozone layer present in the stratosphere.  Thus, ozone layer really protects and helps us a lot to get rid from those harmful radiations but, due to the global warming (which is causing the ozone layer depletion); day-by-day we are getting more exposure to such radiations.

Does UV radiation have any effect on the human hair?

Out of the terrestrial radiations, UV radiations which are harmful for the human hair are UVB which causes protein loss and one is UVA which changes the colour of the hair strands. There are some of the photosensitive amino acids present in the human hair which gets degraded by the sun exposure and hence, produces free radicals as well as cysteic acid after break down of the disulphide bonds. The free radicals and cysteic acid are responsible for the damage of the keratin protein of your hair.

Can your hair naturally prevent the effect of these harmful radiations? 

 Yes! the melanin pigment present in the hair does a protective work by partially immobilising the harmful free radicals formed by UV radiations and also by preventing its entry in the keratin matrix. Melanin pigment is really important for your hair as it absorbs the harmful UV radiations and filters them too. Thus, melanin pigment functions well by protecting your hair protein, through direct and indirect method.  

The hair strands have one outermost layer called as cuticle layer. This layer protects the hair from any kind of damage and imparts shine; when they are in a healthier condition. They make the hair strands water repellent as well as smooth to touch when, the cuticles are in a closed condition.

One more thing works best in case of Asian population and we are fortunate to be a part of Indian population. According to one research article, the African and European hair can get more severely damaged in comparison to Asian hair as they have lesser lipid content in integral part of the hair especially, free fatty acids. In this study, these three hair types were exposed to UVA and UVB radiation for 12 and 48 hours’ interval which showed that Asian hair got lesser damage due to the presence of more lipid content. The African hair suffered severe surface damages and were less resistant to UV radiations. UVB radiations caused much severe damage and breakage of the cuticles in comparison to the UVA radiations.

What measures you can do to protect your hair from UV damage?

Everyone here there mentions about the skin protection against UV rays and sunlight. But, hair damage due to UV rays or sunlight is always hidden or unknown or left unnoticed because the skin damage is noticed very easily while, hair damage is noticed later. Skin conditions like sunburn, suntan, blemishes, hyperpigmentation can be seen and noticed while, hair damage is always difficult to notice.

It is important to check whether your hair gets prolong exposure to the sun. If, it undergoes prolong exposure then, the cuticle of your hair can get damage through UVA or UVB rays. This kind of prolong exposures can cause damage to the shaft of your hair which may lead to discoloration, greying of the hair at an early age, increased brittleness of the hair strands, breakage of hair leading to split ends, thinning of the hair strands and increase in frizzy texture. The heat generate during the sun exposure can make the scalp area sweaty which worsens the condition.   

Does Ayurveda explain anything about Sun damage?

In Ayurveda classical text, it is not directly mentioned that excessive Sun exposures can lead to hair damage. Although, he has mentioned that excessive Pitta dosha in the body can lead to Palitya (hair discoloration), hair thinning and Khalitya (Alopecia) like conditions. As Pitta dosha can be aggravated by any factor which increases the body heat in a person and Sun is the biggest source possible which is responsible to provide heat and energy on earth. Acharya Charaka mentions that when Teja guna (comprises of Pitta dosha and Agni mahabhuta) along with aggravated Vata dosha reaches the blood vessels of the scalp (Shira kapala). Then, it increases the hair fall as it responsible for the damage to hair follicle by causing Dahana to the Romakoop of the Kapala.

How to prevent your hair from Sun damage?

1. Try to cover your hair whenever you get sun exposures. Either wear hat, scarfs, etc before getting exposed to the Sun rays.
2. Apply Coconut oil after the Sun exposure as it will reduce the amount of Pitta dosha accumulated in the scalp.
3. You can go through the Nabhi oiling or nasya procedures with the help of any Ayurvedic doctor. Performing Nasya procedures are good for the growth of your hair.
4. Wash your hair with Amla, Reetha, Shikakai mixtures or you can use freshly prepared aloe gel.
5. Trim your hair at an interval which can help you to get rid of the split ends and thus, prevents any hair fall due to the frizzy hair.

REFERENCES:

1. Jeon SY, Pi LQ, Lee WS. Comparison of hair shaft damage after UVA and UVB irradiation. J Cosmet Sci. 2008 Mar-Apr;59(2):151-6. PMID: 18408872.
2. Ji JH, Park TS, Lee HJ, Kim YD, Pi LQ, Jin XH, Lee WS. The Ethnic Differences of the Damage of Hair and Integral Hair Lipid after Ultra Violet Radiation. Ann Dermatol. 2013 Feb;25(1):5460. https://doi.org/10.5021/ad.2013.25.1.54
3. https://www.vogue.in/beauty/content/heres-how-you-can-protect-your-hair-from-sun-damage-this-summer
4. Charak Samhita chikitsa
5. https://www.researchgate.net/publication/340250248_CONCEPT_OF_HAIR_AND_HAIR_DISEASES_IN_AYURVEDA