Looking at the perspectives of Donguibogam through modern science reveals clear parallels. How does modern medicine explain that hair, described as the surplus of blood, depends on nighttime sleep? A primary factor is cortisol, the stress hormone.
When sleep is insufficient, the body enters a state of severe stress. In response, the adrenal gland secretes excess cortisol. This hormone promotes a systemic inflammatory response, impairs blood circulation, and causes DNA damage to hair follicle cells. Chronically elevated cortisol levels disrupt the hair growth cycle, prompting strands in the anagen phase to transition prematurely into the telogen phase. This constitutes a primary mechanism behind telogen effluvium. Finding excess hair on the pillow each morning or losing strands while washing hair often reflects elevated cortisol caused by stress and sleep deprivation.
Growth hormone and melatonin also play essential roles. Growth hormone, secreted predominantly during deep non-REM sleep stages, is crucial for cellular regeneration and tissue repair throughout the body, directly influencing hair growth and maintenance. When growth hormone is deficient, hair becomes fine, breaks easily, and grows more slowly. Melatonin, while recognized for regulating sleep, also provides powerful antioxidant activity that shields the scalp and hair follicle cells from oxidative stress. Insufficient melatonin secretion leaves hair follicle cells vulnerable to damage, which can lead to alopecia or gray hair. It also directly stimulates hair follicles to support growth.
Sleep is equally vital for circulation. During sound sleep, the parasympathetic nervous system predominates, allowing blood vessels to relax and circulation to flow smoothly. This supplies adequate nutrients and oxygen to the scalp to sustain healthy hair follicles. Conversely, inadequate sleep keeps the sympathetic nerve active, which constricts blood vessels and decreases microvascular blood flow to the scalp. Deprived of adequate nutrition, hair inevitably thins and weakens. Decreased immunity presents further difficulties; sleep deprivation impairs the immune system, worsening scalp inflammation or conditions such as seborrheic dermatitis, which can trigger a cycle of alopecia.
Sleep serves as a biological restorative process. Donguibogam's focus on replenishing blood aligns with modern medicine's emphasis on hormonal balance, cellular repair, improved circulation, and immune support. Sleep is essential not merely for cosmetic reasons, but for systemic health.
