Vasovagal Syncope: Understanding Causes, Symptoms, and Management in South Korea

[Hinews] [Physician's Column] By Seonhee Seok, Director, Haearim Korean Medicine Clinic, Jamsil Branch

Dizziness, headaches, or nausea during a crowded commute or in highly stressful situations may signal a condition known as vasovagal syncope. In 2022, about 22,000 South Koreans received medical care for vasovagal syncope, according to the Health Insurance Review and Assessment Service (HIRA). Experts note, however, that actual cases may be higher due to underdiagnosis and limited public awareness.

To understand vasovagal syncope, it’s essential to grasp the role of the autonomic nervous system, which comprises the sympathetic and parasympathetic nervous systems. These systems work in tandem to maintain the body’s homeostasis. The sympathetic nervous system activates during emergencies, dilating arteries and increasing heart rate, while the parasympathetic system lowers blood pressure and promotes digestion. When this system becomes imbalanced—a condition known as autonomic dysfunction (dysautonomia)—it can cause a wide range of symptoms, including headaches, dizziness, indigestion, dry eyes, excessive sweating, fatigue, insomnia, anxiety, and depression.

Vasovagal syncope specifically involves the vagus nerve, a key component of the parasympathetic system that regulates heart rate. When this nerve becomes overactive, it can cause a sudden drop in heart rate and blood pressure, reducing blood flow to the brain and leading to fainting. This condition often arises from an interplay between the sympathetic and parasympathetic systems, where their opposing roles in regulating organ function become disrupted.

Diagnosis typically involves autonomic function tests, such as the tilt-table test, which monitors heart rate, blood pressure, and symptom onset. Additional tests—such as electrocardiograms (ECG), echocardiograms, blood work, and brain MRI scans—are often used to rule out other potential causes of fainting.

Vasovagal syncope is commonly triggered in scenarios like standing for long periods in places such as military bases or schools, or in confined, oxygen-poor environments.It can also occur during prolonged urination, severe menstrual cramps, or while taking extended hot baths. Crowded public transportation during rush hour is a frequent trigger. If symptoms arise in such settings, experts recommend stepping off to breathe fresh air, drinking water, or resting briefly.

Stressful or frightening situations can overstimulate the sympathetic nervous system, prompting a compensatory overactivation of the parasympathetic system. This reaction can trigger a sudden drop in heart rate and blood pressure, briefly cutting off blood flow to the brain and causing fainting—the hallmark of vasovagal syncope.


Autonomic dysfunction can manifest as various clinical conditions, sometimes presenting with somatic symptoms. For instance, neurogenic gastrointestinal problems—such as indigestion or loss of appetite—may appear even when endoscopic exams show no structural abnormalities like gastritis or esophagitis. Poor blood flow to digestive organs or slowed gastrointestinal motility can cause post-meal bloating, gas, or abdominal distension. Conditions like gastroesophageal reflux disease, neurogenic gastritis, and irritable bowel syndrome are common.

Beyond digestive issues, dysautonomia may cause dizziness, sensory disturbances, tinnitus, headaches, mood disorders, and insomnia. Other possible symptoms include facial flushing, fatigue, recurrent infections (such as colds, cystitis, or vaginitis), numbness in the extremities, brain fog, head pressure, and menstrual irregularities such as dysmenorrhea, PMS, or menopausal complaints. These signs often point to autonomic nervous system irregularities.

When diagnostic tests show no abnormalities, patients may feel anxious or dismissed. Traditional Korean medicine approaches, including herbal treatments and acupuncture, are often used to help restore autonomic balance and support overall health. Lifestyle changes, such as avoiding stress and overwork, ensuring adequate sleep, and engaging in light exercise like walking, are also recommended to promote relaxation and well-being.