Noise pollution in hospitals is regularly exceeding international recommendations, according to new research.
The issue is a common concern among patients, families and staff, a study suggests.
It found four in 10 (40%) patients are bothered by noise at night, which can be loud even in intensive care units.
In an editorial published in the BMJ medical journal, researchers from King's College London and the University of the Arts London (UAL) argue it is a worsening problem.
They warned it can impact patients' ability to rest, heal and recover, as noise has been linked to hospital-induced stress, increased pain sensitivity, high blood pressure and poor mental health.
Lead author Dr Andreas Xyrichis said: "Even in intensive care units, which cater for the most vulnerable patients, noise levels over 100dB have been measured, the equivalent of loud music through headphones."
Noise in hospitals is also known to hinder communication among staff, causing annoyance, irritation and fatigue, detrimentally impacting the quality and safety of healthcare.
High noise levels and noise-induced stress can impact negatively on staff performance and well-being, compromising caring behaviour and contributing to burnout, they said.
Dr Xyrichis added: "We know hospital noise has disruptive consequences for sleep - machine sounds in particular have a greater negative effect on arousal than human voices.
"Post-hospitalisation recovery is also compromised.
"For example, coronary care patients treated during noisy periods were found to have a higher incidence of rehospitalisation compared to those treated during quieter periods."
Patients who are in hospital for several nights have spoken of feeling trapped and stressed, leading to requests for premature discharge and heightened risk of trauma and readmission.
The team said ways to measure patients' perceptions of noise up to this point have been limited and so more research is needed in this area.
They pointed out there are a number of potential sources of noise in hospitals - such as alarms, televisions, rattling trolleys and ringing phones, as well as staff, visitor, and patient conversations.
Not all of them are perceived as noise by patients - for example, some find the sound of the tea trolley pleasing, associating it with receiving a warm drink.
Dr Xyrichis said: "Measures to tackle this problem have included ear plugs, noise warning systems, acoustic treatment panels, educational initiatives and noise reduction protocols, which have provided some benefit.
"However, so far, patients have been seen as passive recipients of hospital noise rather than active participants in its creation.
"It is essential that future solutions should have greater patient participation as a key feature.
"Guides about potential ward sounds could also enhance patients' understanding of their surroundings and increase relaxation.
"Sound masking - the addition of background, broadband sound optimised for particular environments to reduce noise-induced disturbance - has also been used widely in open-plan offices for many years and has recently shown promise for improving sleep in hospitals."
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Peter Byrne / PA Wire.