Modern medicine articulates the insights of Donguibogam through scientific mechanisms. The caffeine consumed daily in coffee exerts a potent effect on the nervous system. Caffeine works by blocking adenosine receptors in the brain. Adenosine is a compound that promotes feelings of tiredness and supports sleep onset. When caffeine occupies these receptors, the brain cannot readily detect fatigue signals and remains in an aroused state.
Beyond this, caffeine stimulates the sympathetic nervous system, prompting a fight-or-flight response. When the sympathetic nerve is activated, the adrenal medulla releases catecholamines, specifically epinephrine and norepinephrine. These hormones increase heart rate, elevate heart contractility, and constrict blood vessels to raise blood pressure. This physiological shift is why coffee can produce noticeable palpitations. While this state may temporarily sharpen focus, prolonged elevation places measurable strain on the cardiovascular system.
When sympathetic hyperactivity continues unchecked, the hypothalamic-pituitary-adrenal axis remains persistently engaged. This elevates stress hormones such as cortisol and can contribute to persistent anxiety, restlessness, and sensations similar to a panic attack. Ongoing palpitations, chest tightness, and hand tremors frequently stem from this heightened sympathetic activation.
Caffeine also significantly alters sleep architecture. Its stimulating effects can persist for hours following consumption. Coffee consumed in the late afternoon or evening suppresses melatonin secretion and reduces sleep quality, contributing to insomnia. It impairs deep sleep and alters the cycles between non-REM sleep and REM sleep, leaving people feeling unrefreshed and chronically tired despite resting. This often leads to a cycle of consuming more caffeine the following day.
The body is built to remain active during the day and recover at night. When caffeine continually drives the heart during daytime hours and compromises rest at night, autonomic nervous system regulation gradually weakens, potentially leading to broader concerns. Hypertension, arrhythmia, digestive disorders, and feelings of lethargy or low mood can all be connected to an autonomic nervous system imbalance triggered by caffeine.
