A single night of noise exposure can do more than just disrupt sleep — it can damage blood vessel health, according to a new study. The finding that common urban traffic noise may be directly linked to cardiovascular disease risk is raising the issue to a public health concern.
◇ Even One Night Impairs Vascular Function
A research team at Johannes Gutenberg University Mainz in Germany analyzed the effects of nighttime traffic noise on 74 healthy adults, according to a study published in the international journal *Cardiovascular Research*.
The study was conducted using a randomized, double-blind crossover design. Participants experienced three separate nights: one with no noise, one with 30 traffic noise events, and one with 60 traffic noise events. The noise was played using recordings from actual roads at a maximum level of approximately 60 decibels (dB) — a level commonly experienced in urban apartments or homes near roadways.
The results were clear. Flow-mediated dilation (FMD), a measure of blood vessels' ability to expand, averaged 9.35% after the silent night but dropped to 8.19% after 30 noise events and 7.73% after 60 events. Reduced FMD means blood vessels fail to relax properly, which is directly linked to increased cardiovascular disease risk.
The researchers said "endothelial dysfunction" was observed after just a single night of exposure. The vascular endothelium regulates contraction and relaxation of blood vessels and suppresses inflammation. When its function deteriorates, it can lead to atherosclerosis, hypertension, myocardial infarction and stroke.
◇ "Already Exceeding Standards" — Korea Is No Exception
The problem is not confined to specific regions. The European Environment Agency (EEA) estimates that approximately 150 million people — about 30% of Europe's population — are chronically exposed to traffic noise exceeding the World Health Organization (WHO) guideline of 55 dB.
Korea faces a similar situation. A 2025 joint study by the Seoul Metropolitan Government Research Institute of Public Health and Environment and the University of Seoul found that daytime noise levels in major urban areas including City Hall Station, Sinchon Station, Sinsa Station and Seongsu-dong ranged from 66 to 72 dB, consistently exceeding the WHO guideline of 60 dB. Nighttime noise also ranged from 61 to 69 dB, far surpassing the recommended level of 50 dB.
The study also found that areas where daytime noise exceeded 70 dB showed a relative risk of myocardial infarction more than 20% higher than areas at 60 dB or below.
Experts stress that nighttime noise should be treated not as a mere lifestyle inconvenience but as a public health risk factor. They point to the need for structural measures such as low-noise road pavement, traffic volume management and expanded urban green buffer zones.
At the individual level, recommendations include positioning bedrooms on the side opposite to roads, installing soundproof windows, and using earplugs or noise-blocking curtains. However, the researchers emphasized that "the most effective solution lies in societal and environmental improvements, not individual action."
The study has limitations, as it was a short-term experiment involving young, healthy adults. The research team noted that "further studies are needed to determine how changes in blood protein levels translate into long-term cardiovascular disease."