The wisdom of Donguibogam contains remarkable insights that can also be explained by modern medicine. The mechanism by which stress disrupts sleep is explained very clearly in neurological and endocrinological terms. When we experience stress, the brain's hypothalamic-pituitary-adrenal axis is activated, excessively secreting stress hormones such as cortisol that trigger the fight-or-flight response. Cortisol is originally secreted at its highest level in the morning to give us energy for daily activities, but under chronic stress, its levels remain high even at night, keeping our body in a continuous state of tension. This is a decisive factor that prevents the brain from preparing for sleep.
In addition, stress excessively activates the sympathetic nervous system. The sympathetic nervous system plays a role in keeping us aroused and boosting energy, but when it remains hyperactivated into the night, heart rate accelerates, blood pressure rises, and muscles tense up. Conversely, the activity of the parasympathetic nervous system, which relaxes us and supports rest, is suppressed. This imbalance inhibits the secretion of melatonin, the hormone that induces sleep, and makes it difficult for the brain to enter a relaxed state characterized by alpha waves. Ultimately, this makes the cycles of REM sleep and non-REM sleep irregular, disrupts deep sleep, and causes a sharp drop in sleep quality.
Furthermore, stress adversely affects the balance of neurotransmitters in the brain. The function of gamma-aminobutyric acid, which relieves anxiety and tension, declines, and problems can arise in the secretion of serotonin, which is crucial for mood and sleep regulation. The sense of stuffiness from liver qi depression can be neurologically related to decreased frontal lobe function, and disquieted heart-spirit can be linked to hyperactivation of the amygdala. These complex factors prevent our brain from resting each night, ultimately creating a vicious cycle that leads to chronic insomnia and anxiety disorders. Going beyond merely being unable to fall asleep, because the brain does not get sufficient time to recover and process information, this can spread to various problems during the day such as impaired concentration, memory impairment, and difficulty regulating emotions, so it must never be taken lightly.
