Unable to Sleep at Night: Could Your Brain Be Overheated from 'Upper Heat and Lower Cold'?

The imbalance of the 'triple energizer' and the symptoms of 'upper heat and lower cold' described in the Donguibogam are very closely linked in modern medicine to abnormalities in the 'autonomic nervous system', the core control system of our body. The autonomic nervous system consists of the sympathetic nerve and the parasympathetic nerve. The sympathetic nerve is responsible for the 'emergency mode' that makes us fight or flee when in danger. It accelerates the heart rate, tenses muscles, and heightens mental alertness. Conversely, the parasympathetic nerve handles the 'rest mode' that comfortably relaxes the body, aids digestion, and brings on sleep. These two nerves must maintain balance like a seesaw to preserve our body's homeostasis. However, modern people suffering from chronic stress and irregular lifestyle habits often develop sympathetic hyperactivity. 'Upward heat'—meaning that the head and chest become hot and one feels anxiety, insomnia, and chest tightness—is caused precisely by this hyperactivation of the sympathetic nerve. In the brain, excitatory neurotransmitters such as norepinephrine and glutamate are secreted excessively, placing the brain in an 'overheated' state, while melatonin secretion that induces deep sleep declines or the sleep cycle becomes disrupted. The secretion of cortisol, a stress hormone, also continues late into the night, keeping the body in a constant state of arousal. At the same time, 'lower body cold'—symptoms such as cold hands and feet or a chilly lower abdomen—may appear as peripheral blood vessels constrict due to sympathetic hyperactivity, shunting blood primarily to vital organs like the heart and brain. It is also related to decreased digestive function or slowed intestinal motility because the parasympathetic nerve cannot function properly. Such autonomic nervous system imbalance leads to dysfunction of the hypothalamic-pituitary-adrenal axis, causing hormonal imbalance and triggering a microinflammatory response throughout the body that can adversely affect brain function and emotional regulation. Ultimately, one falls into a vicious cycle where both body and mind become exhausted. Do not forget that sleepless nights and chest tightness are powerful warning signs sent by your body.