Anyone who has ever stayed overnight in a hospital will know how difficult it can be to sleep, surrounded by staff, machinery, trolleys and telephones. In the UK, 40% of hospital patients are bothered by noise at night, according to in-patient surveys. But it’s not only the patients’ wellbeing that may be affected – high noise levels can also have an impact on staff performance and burnout rates. Researchers from King’s College London say noise levels in intensive care – where the most vulnerable patients are looked after – regularly exceed 100 decibels. That’s the equivalent of loud music being played through headphones. And it’s not just the frustration of being unable to hear each other speak or the fatigue and irritation sparked by poor sleep that are causing concern. At that level, noise pollution has been implicated in the development of a condition known as intensive care psychosis – a form of delirium where patients experience anxiety, become paranoid, hear voices and see things that are not there. Increased stress, greater pain sensitivity, high blood pressure, and poor mental health are also possible side-effects. It means patients often decide to leave hospital before they are completely better – only to be re-admitted at a later stage. Coronary care patients treated during noisy periods were found to have a higher incidence of rehospitalisation, compared with those treated during quieter periods. “People leave early, and long after discharge the trauma remains. It puts patients off coming back,” Dr Andreas Xyrichis, lead author of the report, told the BBC. For staff, a noisy working environment is unavoidable – but the consequent stress can affect their performance, while the difficulties of hearing each other and patients speak can compromise the quality and safety of healthcare.