Road traffic noise at night is not music to the ears - and the heart.Exposure to night-time road traffic noise (RTN) appears to adversely affect cardiovascular (CV) health, according to a study.
“Even a single night of RTN stressed the CV system. We did not expect to find such consistent biological changes in people exposed to noise levels typical of someone living near a road,” explained lead author Dr Omar Hahad from the University Medical Center of Johannes Gutenberg-University, Mainz, Germany, in a press release.
Seventy-four healthy participants were exposed to three overnight conditions: no noise (control), and 30 and 60 recorded RTN events. The average sound pressure levels were 30.70, 41.36, and 44.13 dB, respectively. The primary endpoint was endothelial function evaluated by flow-mediated dilation (FMD) the morning after each night. A subgroup of participants was given vitamin C to evaluate the involvement of oxidative stress. [Cardiovasc Res 2026;doi:10.1093/cvr/cvag028]
Compared with the control arm, the 30-event arm had significant reductions in FMD (8.19 percent vs 9.35 percent; mean difference [MD], 1.16 percent; p=0.005), as did the 60-event arm (7.73 percent vs 9.35 percent; MD, 1.63 percent; p<0.0001).
“The observed reduction in FMD following both event exposures confirms the sensitivity of endothelial function to short-term environmental noise exposure,” the investigators explained in the published manuscript. The results align with evidence showing impaired FMD due to aircraft or train noise. [Eur Heart J 2013;34:3508-3514a; Clin Res Cardiol 2015;104:23-30; Cardiovasc Res 2021;117:1382-1390; Basic Res Cardiol 2019;114:46]
In the subgroup analysis, a trend was observed with 60 events (MD, 1.02 percent; p=0.0856), implying a potential, albeit inconclusive, vascular benefit, the researchers said. “The absence of a significant effect may reflect suboptimal timing, insufficient dosage, or the dominance of nonoxidative mechanisms such as inflammatory or neurohormonal activation in acute RTN responses.”
RTN exposure was associated with a substantial increase in RTN annoyance and deterioration across all dimensions of subjective sleep quality evaluated: reduced sleep quality, depth, and duration, and increased restlessness, difficulty falling asleep, and morning exhaustion.
Sleep was rated as less restful and worse than normal under both noise conditions. According to the researchers, the number of movements during sleep and the perception of sleep as more exhausting and stressful increased with RTN exposure.
“Even when we are asleep, our bodies are still listening. Repeated activation of stress responses night after night may help explain why people exposed to long-term RTN have higher rates of high blood pressure and heart disease,” Hahad said. “Protecting our sleep by tackling noise pollution should be part of how we think about preventing CV disease in towns and cities around the world.”
Heart rate (HR) was markedly elevated in the 60-event vs the control arm (average: MD, 1.23 bpm; p=0.04; maximum: MD, 7.95 bpm; p<0.001). Noise exposure also increased the odds of post-noise HR peaks (odds ratios, 1.89 and 2.42 for 30 and 60 events, respectively). “The increased night-time HR under RTN conditions reflects acute autonomic activation in response to repeated noise events,” said the researchers.
However, given the young, healthy study population, the findings may not be extrapolated to older cohorts or those with comorbidities. The short study duration also warrants longer-term studies to ascertain the cumulative impact of long-term exposure.
“[Nonetheless,] given that endothelial dysfunction is an established precursor to atherosclerosis and predictive of future CV events, these findings carry direct clinical relevance. This highlights the need for precise preventive strategies that address environmental determinants of CV health,” the researchers noted.
The results reinforce evidence that environmental noise is not just a nuisance but a modifiable CV risk factor, support calls by the WHO and European Society of Cardiology for stricter noise regulation, and underpin the need for urban planning to protect sleep and vascular health in highly noise-polluted environments, they stressed.
“The biggest positive impact would come from structural and societal measures, such as reducing traffic at night, quieter road surfaces, better urban planning, and good building insulation,” Hahad noted.
The researchers also recommended personal noise-mitigation strategies for city dwellers to cope with the concrete jungle noise.
“Reducing bedroom noise exposure where possible is a reasonable measure, by moving bedrooms away from the road or [by insulating] windows,” Hahad said. Although evidence is lacking, earplugs may be worth considering for reducing the RTN burden. Lifestyle shifts (healthy diets, exercise) may also be protective, he added.