Heart Thumping: For You Whose Heart Races from Stress

Modern medicine explains the connection between the heart and the mind described in Donguibogam through the action of the autonomic nervous system. When we feel stress or anxiety, our body instinctively initiates a fight-or-flight response to cope with threats. The sympathetic nervous system plays the leading role in this process. When the sympathetic nervous system is activated, the hypothalamus immediately stimulates the adrenal gland to secrete hormones called epinephrine, also known as adrenaline, and norepinephrine. These hormones sharply increase the heart rate and strengthen cardiac contractility to pump blood faster and more forcefully, as if an alarm sounded in the heart. Blood pressure also rises, and muscles throughout the body enter a state of tension. This was a survival response for ancient humans to quickly flee or prepare to fight when encountering wild beasts. In modern society, however, psychological stress such as reprimands from a supervisor, exam pressure, and worry about the future triggers the exact same biological response. Chronic stress goes beyond momentary sympathetic activation and continuously stimulates the hypothalamic-pituitary-adrenal axis. Because of this, the stress hormone cortisol is secreted at high concentrations over a long period, disrupting the body's balance. Cortisol affects several organs including the heart, further amplifies anxiety, and can place a long-term burden on the cardiovascular system, creating a situation where the heart is constantly overloaded. In addition, the parasympathetic nervous system, represented by the vagus nerve, functions to lower heart rate and relax the body. Under chronic stress, the function of this parasympathetic nerve weakens, preventing the body from properly switching into rest mode. Much like a car where the accelerator is pressed without applying the brakes, the heart continues running at high speed. This autonomic nervous system imbalance also becomes a major cause of various mental health issues such as anxiety disorder and panic disorder. Palpitations may also be a sign of underlying conditions such as heart disease, hyperthyroidism, and anemia, so if symptoms are severe or recurring, consulting a healthcare professional for an accurate diagnosis is essential. Attending to the body's small signals is an important first step toward sustaining health.