Music, White Noise and Nature Sounds May Help Hospital Patients Sleep Better, Review Finds

Hospital rooms are supposed to be places of healing, yet for millions of patients every year they become environments of relentless sensory assault. Alarms shriek, monitors beep, staff conversations echo through corridors at all hours, and fluorescent lighting erases any meaningful distinction between day and night. Against this backdrop, a new systematic review published in iScience suggests that one of the simplest and cheapest remedies available to clinicians, therapeutic sound, may meaningfully improve the sleep of hospitalized adults. The review, led by Helga Rafael Henriques of the Lisbon School of Nursing and colleagues, pooled data from fifteen studies involving more than two thousand patients and found that sound-based interventions were associated with a large, statistically significant improvement in self-reported sleep quality.

The stakes of hospital sleep are far higher than mere comfort. Sleep is governed by a complex interplay of psychological, electrophysiological, neurochemical, endocrinological, immunological, and genetic factors, and it is essential for maintaining and restoring both mental and physical health. When that sleep is fragmented, the consequences cascade through the body: cardiovascular dysfunction, delirium and other cognitive disturbances, impaired psychomotor control that raises the risk of falls, heightened anxiety, increased pain perception, metabolic disruption, immune dysfunction, and proinflammatory states. Worryingly, research cited in the review indicates that sleep disturbance can persist for up to twelve months after a patient leaves the hospital, making the inpatient period a critical window for intervention.

The idea that the acoustic environment matters in hospitals is not new. Florence Nightingale wrote about the therapeutic hospital environment more than a century and a half ago, and early experimental work established that white noise could mask disruptive sounds and ease sleep onset. By the early 1990s, randomized trials were testing recorded nature sounds in hospitalized adults, including a study of ocean sounds in cardiac surgery patients. Yet despite decades of interest, no previous synthesis had quantitatively compared the major categories of sound-based interventions, music, white noise, and nature sounds, across both intensive care units and general wards, or examined how delivery format might moderate their effects. The new review was designed to close exactly that gap, and its protocol was prospectively registered with PROSPERO.

Methodologically, the team followed a structured PICO framework, searching five major databases, MEDLINE, CINAHL, the Cochrane Library, Web of Science, and Scopus, without temporal limits, and screening records in the Rayyan platform with at least two independent reviewers at every stage. From 1,524 initial records, the researchers ultimately included fifteen studies published between 2012 and 2026: ten randomized controlled trials and five quasi-experimental studies, encompassing 2,024 participants. The interventions ranged widely, from sedating piano music and Chopin Nocturnes to patient-selected playlists, traditional Chinese five-phase music, ocean sounds, and broadband white noise, delivered for anywhere between five minutes and an entire night, almost always in the evening hours before sleep.

Because the included studies measured sleep with different instruments, the reviewers used the standardized mean difference as their primary effect measure, pooling estimates with a random-effects DerSimonian-Laird model. The result was striking: sound-based interventions were associated with a large improvement in sleep quality, with a pooled standardized mean difference of 1.71 (95 percent confidence interval 0.96 to 2.46; p < 0.00001). A sensitivity analysis that excluded the lowest-quality study, a quasi-experimental trial of white noise in a coronary care unit that scored just 44 percent on the Joanna Briggs Institute appraisal checklist, yielded a somewhat smaller but still large and significant estimate of 1.54. Subgroup analyses confirmed the effect in both randomized trials alone (SMD 1.50) and quasi-experimental studies alone (SMD 2.08), suggesting the finding was not an artifact of pooling different designs.

The authors are candid about the caveats. Heterogeneity across studies was extreme, with an I-squared statistic of 96 percent, meaning nearly all of the observed variability in effect sizes reflected genuine differences between trials rather than chance. Those differences were substantial: interventions varied in type, duration, and delivery format; most studies took place in intensive care units while a handful occurred in surgical or cardiac wards; and in six studies patients chose their own music while in nine the investigators selected it. The largest individual effect size in the pooled analysis came from the lowest-quality study, and the appraisal scores ranged from 44 to 100 percent, with most randomized trials scoring between 62 and 77 percent. Common weaknesses included absent allocation concealment and a near-total lack of blinding, which is difficult when the intervention is audible, but not impossible with sham conditions such as silent headphones.

Why might sound help at all? The review outlines three complementary mechanisms that likely differ by stimulus type. Masking sounds such as white noise are thought to raise the auditory arousal threshold: a continuous, non-alerting background reduces the acoustic contrast created by intermittent alarms and conversations, making the cerebral cortex less likely to register them as arousal-triggering events. Calming or preference-matched music, by contrast, appears to act through autonomic and neuroendocrine pathways, since auditory input projects not only to the auditory cortex but also to limbic structures involved in emotional regulation, promoting parasympathetic activation, dampening sympathetic arousal, and attenuating cortisol and catecholamine release. A third, more targeted approach, closed-loop acoustic stimulation timed to endogenous slow-wave oscillations, has been shown to directly enhance slow-wave activity, hinting at a distinct neurophysiological pathway that future hospital interventions might exploit.

The evidence on combining sound with other measures was more equivocal. Eight of the twelve pooled comparisons paired sound with an adjunct, earplugs, eye masks, massage, aromatherapy, relaxation exercises, or even intelligent noise-control technology, and these combined interventions produced effects ranging from negligible to enormous. Sound-alone comparisons were consistently positive but varied widely in magnitude. The only head-to-head comparison within a single sample, a crossover trial in India, found that earplugs plus an eye mask outperformed ocean sound alone. The authors caution that with so few studies per category, these patterns should be read descriptively rather than as proof of synergy; larger trials with common comparator arms are needed to determine whether bundling genuinely adds benefit beyond sound itself.

For clinicians, the practical implications are immediate and low-cost. The review proposes a stepwise nursing pathway: assess each patient’s sound preferences and any contraindications such as hearing impairment at admission; deliver preferred audio through headphones or bedside speakers to avoid disturbing roommates; schedule the intervention within the evening routine while clustering nursing procedures beforehand to minimize interruptions; document the intervention and the patient’s response; and reassess preferences periodically as hospitalization progresses. The authors also emphasize the broader environmental context. The World Health Organization recommends that hospital sound levels not exceed 35 decibels by day and 40 decibels at night, yet measured hospital noise routinely spans 37 to 88.6 decibels during the day and up to nearly 69 decibels at night, a gap that no playlist can fully bridge on its own.

Ultimately, the review lands on a message of cautious optimism. Sound-based interventions, whether classical music, relaxation melodies, nature sounds, or white noise, appear to offer hospitalized patients a real, drug-free boost to sleep quality, particularly when tailored to individual preferences, and they can be implemented by nursing staff without specialized equipment. But the field’s reliance on heterogeneous subjective questionnaires, none of the included studies used objective measures such as actigraphy or polysomnography as a primary outcome, and its patchy methodological rigor temper confidence in any single number. The authors call for larger, better-designed randomized trials that test each sound type in isolation, use validated instruments with appropriate recall windows, and report outcomes stratified by setting and selection method. Until then, the humble headphone may be one of the most underused tools in the hospital ward.

Subject of Research: Effectiveness of sound-based interventions for improving sleep quality in hospitalized adult patients

Article Title: The effectiveness of sound-based interventions on promoting sleep quality in hospitalized patients: A systematic review

Article References: Henriques, H. R., Silva, M. P., Guerreiro, R., Mendonça, S. C., Durão, C., Rosario Pinto, M., & Teixeira, J. (2026). The effectiveness of sound-based interventions on promoting sleep quality in hospitalized patients: A systematic review. iScience, 29(10), Article 117698. https://doi.org/10.1016/j.isci.2026.117698

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117698

Keywords: sleep quality, hospitalized patients, sound-based interventions, music therapy, white noise, nature sounds, intensive care unit, systematic review, meta-analysis, nursing, non-pharmacological interventions, delirium