Singer Lee Sang-soon has stepped away from hosting his radio program after being told he has reduced vagus nerve function. The term is unfamiliar to most people, but a related condition — vasovagal syncope — is common enough that 20% to 30% of the population experiences it at least once in their lifetime. Symptoms range from sudden dizziness to a loss of consciousness in severe cases. So what exactly happens in the body?
Vasovagal Syncope: One in Three People Faint at Least Once
About 23,000 patients received hospital treatment for vasovagal syncope in 2025, according to data from the Health Insurance Review and Assessment Service. That is a slight increase from about 22,000 in 2022.
Vasovagal syncope is considered the most common type of fainting. Roughly half of patients who visit emergency rooms for fainting are diagnosed with it, and an estimated 20% to 30% of people worldwide experience it at least once in their lives. The condition occurs about 1.5 times more frequently in women than in men.
The vagus nerve runs from the brain to major organs including the heart, lungs and digestive tract, and serves as the core of the parasympathetic nervous system. It helps the body maintain a stable state by slowing the heart rate and regulating digestion.
Vasovagal syncope is one of the most common conditions linked to the vagus nerve. Triggers can include stress, pain, standing for long periods, sudden changes in posture, hot weather and dehydration.
When a specific trigger temporarily disrupts the balance of the autonomic nervous system, the heart rate slows and blood vessels dilate, causing blood pressure to drop. Reduced blood flow to the brain then leads to a momentary loss of consciousness.
Warning signs before fainting can include dizziness, blurred vision, cold sweats, nausea, pallor, palpitations and ringing in the ears. Most people recover quickly, but anyone who faints for the first time or experiences repeated episodes needs professional evaluation to rule out other heart or nervous system disorders.
Lee's Sudden Decline: 'I Will Come Back Recovered'
Lee, a singer and guitarist, recently underwent tests after a sudden deterioration in his health and was told he had reduced vagus nerve function, prompting him to suspend his activities.
His agency, Antenna, said on the 6th through its official social media account that Lee had received hospital treatment after a sudden decline in his condition and was resting on the advice of his medical team.
Lee posted on social media the same day, explaining that his condition worsened abruptly on the 26th of last month, making it difficult for him to host his radio show. He said he has since undergone multiple tests and consultations and is now waiting for the results of additional detailed examinations.
Lee had been hosting MBC FM4U's "A Perfect Day, This Is Lee Sang-soon," but has not appeared on any live broadcast since the 26th of last month, apart from a pre-recorded show that aired on the 29th.
"They tell me I can gradually recover if I get enough rest and stay stable," Lee said. "I want to take enough time on this occasion and come back after recovering my health more fully."
The agency said his future schedule would be adjusted according to his recovery and that it would support him so he can focus on treatment and rest.
Still, the reduced vagus nerve function Lee described cannot be equated with a diagnosis of vasovagal syncope. Because Lee said he is still awaiting detailed test results, the specific symptoms and underlying cause have not been confirmed.
Vasovagal syncope can be managed in most cases through lifestyle adjustments. It helps to sit or lie down immediately and raise the legs when warning signs appear, and to avoid standing for long periods and becoming dehydrated. Yoon Ji-eun, a professor of neurology at Soonchunhyang University Bucheon Hospital, advised that while most cases follow a benign course, a first episode of fainting should be checked by a specialist to rule out other serious causes.
