We already know that lack of sleep has negative effects on the skin. However, it also impacts the condition and health of our hair. Let's focus on these potential effects.
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The consequences of a lack of sleep on your hair
Summary
- Lack of sleep causes scalp itchiness
- Lack of sleep impacts hair growth
- Lack of sleep promotes the appearance of white hair
- Sources
Published March 6, 2024,
updated on October 9, 2024,
by
Kahina, Scientific Editor
—
5 min read
Lack of sleep causes scalp itchiness
Lack of sleep directly impacts the health of the skin and therefore the scalp. It's worth recalling that in an experiment conducted in 2019, Elma D. BARON and her colleagues found that night shift workers were more prone to skin conditions accompanied by itching, particularly seborrheic dermatitis . This skin disease is characterised by red patches covered with flakes on the scalp.
Indeed, a lack of sleep increases the levels of pro-inflammatory cytokines such as TNF-α, which promote cell differentiation, oncogenesis, and the pathogenesis of inflammatory skin conditions. Additionally, reactive oxygen species (ROS) will be produced. All cellular macromolecules, including lipids, proteins, nucleic acids, and polyunsaturated fatty acids of cell membranes, can be affected by excess oxidants which will carry out an electron transfer. This then triggers a chain reaction that causes cellular damage, inflammation, and itching.
Furthermore, skin dryness can induce itching. Numerous cellular functions are orchestrated by the circadian rhythm, which is the internal clock synchronised with the light-dark cycle of the environment. Sleep creates a micro-environment conducive to the migration, differentiation, and proliferation of cells. Circadian clock genes (CLOCK) or hormones, such as melatonin and cortisol, mediate these effects. Consequently, poor cell regeneration results in an accumulation of dead cells on the skin's surface. The sensations of irritation and itching are exacerbated by this situation.
Lack of sleep impacts hair growth
Cortisol, the primary stress hormone in humans, is typically secreted more during the day in response to everyday stressful situations. However, an abnormally high level of cortisol at night can be caused by a stress factor during sleep, which disrupts its smooth progression.
A team led by Dr. Ya-Chieh Hsu from Harvard University has studied the mechanisms that link stress, including lack of sleep, to hair growth. The researchers tested the role of the adrenal glands, which produce corticosterone in rodents and cortisol in humans. The removal of these glands in mice led to rapid cycles of hair regrowth. The stem cells of the hair follicles continued to grow and regenerate the hair follicles. This situation returned to normal after administering corticosterone to the mice. Furthermore, by subjecting the mice to mild stress for several weeks, corticosterone levels increased and hair growth was reduced.
By eliminating the corticosterone receptor in various cells, scientists have determined that the hormone acts on a group of cells located beneath the hair follicle, known as the dermal papilla. Studies have revealed that corticosterone prevents the dermal papilla from secreting GAS6, a molecule they have shown can activate the hair follicle's stem cells. Administering GAS6 into the skin restored hair growth in mice fed corticosterone or subjected to chronic stress. These findings collectively confirm the role of corticosterone in theinhibition of hair regrowth and thus the negative impact of stressors such as lack of sleep on hair growth.
Lack of sleep promotes the appearance of white hair
As previously mentioned, lack of sleep promotes the production of ROS, thus inducing oxidative stress. Experimental evidence supports the hypothesis that oxidative stress plays a major role in the ageing process. With age or during stress such as sleep deprivation, the production of free radicals increases, while endogenous defence mechanisms decrease.
This imbalance leads to a gradual deterioration of cellular structures, which is likely the cause of the phenotype of hair ageing that manifests as a decrease in the function of melanocytes, through the reduction of the activity of tyrosinase, a key enzyme in the melanogenesis process. This then results in hair greying. Fatigue due to lack of sleep thus results in a loss of hair colour.
Sources
TERLECKY S. R. & al. Reactive oxygen species in tumor necrosis factor-α-activated primary human keratinocytes: Implications for psoriasis and inflammatory skin disease. Journal of Investigative Dermatology (2008).
TRÜEB R. M. Oxidative stress in ageing of hair. International Journal of Trichology (2009).
BARON E.D. & al. The effect of shift work and poor sleep on self-reported skin conditions: A survey of call center agents in the Philippines. Clocks and Sleep (2019).
STAUBACH P. & al. Sleep disturbance in patients with urticaria and atopic dermatitis: An underestimated burden. Acta Dermato-Venereologica (2020).
HSU Y. C. & al. Corticosterone inhibits GAS6 to govern hair follicle stem-cell quiescence. Nature (2021).
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