Terror Arriving in Sleep, 'Nocturnal Panic Attack': Could It Be You Too?

The instability of the 'spirit' governed by the 'heart' described in Donguibogam can be understood in modern medicine as dysregulation of the central nervous system and autonomic nervous system. The amygdala serves as the core brain region processing fear and anxiety. Under chronic stress or excessive arousal, this structure becomes hypersensitive, much like an alarm system ringing loudly at the slightest sound. When we fall asleep or enter deep sleep, our body rests, yet the brain remains active, cycling through various sleep stages. During the transition from NREM sleep to REM sleep, or when brief arousal occurs during deep NREM sleep, a hypersensitive amygdala can misfire and trigger a sudden fear response. This leads to a rapid surge of stress hormones such as norepinephrine and cortisol, producing classic panic symptoms including palpitations, rapid breathing, and cold sweats. An impaired autonomic nervous system balance also plays a significant role. Cardiac function should maintain a relaxed state through parasympathetic nervous system dominance. When the sympathetic nerve becomes excessively heightened, it burdens the cardiovascular system by reducing heart rate variability and elevating blood pressure. This state correlates with a decline in stress resilience, the modern counterpart to the classical concept of courage. Innate temperament or prolonged stress can erode this resilience, leaving one prone to feeling anxious over minor triggers. Furthermore, when accompanied by other sleep disorders such as sleep apnea or restless legs syndrome, the brain cannot rest adequately and experiences stress from hypoxia or frequent arousal, increasing the risk of nocturnal panic attacks. These occurrences are complex signals where the heart, brain, hormones, and nervous system interact closely, showing that a harmonious recovery of both body and mind beyond simple insomnia is needed.