Loud noises are more than just annoying — they can affect you at a cellular level, a new study has revealed.

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Much like air pollution, noise pollution also increases the risk of disease, but there’s still a lot of controversy around how it does so.

Plenty of anecdotal and empirical evidence has linked environmental noises to a series of health issues. More than simply disrupting our sleep and moments of relaxation, constant noises also seem to take a significant toll on our body.

Traffic noise, for instance, has been linked to an increase in the risk of heart disease, but no mechanism has been discovered that explains this increased incidence. Now, in a new review, scientists describe how that happens.

Thomas Munzel, lead author of the study, believes there is now plenty of evidence that noise makes you sick. After carrying out a review of previous studies, he and his team concluded that noise induces a stress response through the sympathetic nervous system — the system which activates the so-called fight or flight response. In turn, this increases hormone levels, which ultimately leads to vascular damage and several other metabolic abnormalities.

If this is the case, then it supports the idea that transportation noise contributes to the development of heart disease risk factors such as hypertension and diabetes. This was previously suggested in both animal and human studies.

However, this is still an open debate, as the effect of noise pollution is extremely difficult from other influences. For instance, people living next to noisy roads are also more exposed to noise pollution, but houses near such roads also tend to be cheaper, which means that, on average, the occupants of the houses have lower incomes and therefore might not be able to afford healthier foods. It’s a complex issue, but at least for now, increasing evidence seems to indicate that noise is indeed a cause of health concern.

The World Health Organization calls noise pollution “an underestimated threat” that can cause “sleep disturbance, cardiovascular effects, poorer work and school performance, hearing impairment.” The agency recommends less than 30 A-weighted decibels in the bedroom for a good night’s sleep.

Researchers also suggest that this is something policymakers should work towards fixing, as more and more of the population is exposed to transportation noise.

“As the percentage of the population exposed to detrimental levels of transportation noise are rising, new developments and legislation to reduce noise are important for public health,” Münzel concludes.

Journal Reference: Thomas Münzel, Frank P. Schmidt, Sebastian Steven, Johannes Herzog, Andreas Daiber and Mette Sørensen. Environmental Noise and the Cardiovascular System. DOI: 10.1016/j.jacc.2017.12.015