Effects of personal control over hospital noise on sleep.
Critical Care Unit (CCU) sound levels, subjective stress due to noise, and sleep were studied in 105 female volunteers in a simulated hospital environment. Subjects were randomly assigned to instruction in personal control over noise via the availability of a sound conditioner, no instruction in personal control over noise, or quiet conditions. Subjects in the two noise conditions heard audiotape-recorded CCU nighttime sounds while attempting to sleep overnight in the laboratory. The intervention did not facilitate better sleep as measured by polysomnograph equipment and self-report. However, the results provided strong support for a causal relationship between CCU sounds and poorer sleep. When compared to the quiet condition, subjects in the noise conditions had poorer sleep efficiency; more difficulty falling and staying asleep; more difficulty progressing from one stage of sleep to the next; more intrasleep awakenings; spent less time in Rapid Eye Movement sleep; and poorer sleep via self-report (all ps less than .03). As predicted, scores for subjective stress due to CCU sounds yielded significant relationships with 9 of 16 measures of sleep (all ps less than .01). Hierarchical multiple regressions showed that 13% (p less than .001) and close to 6% (p less than .05) of the variance in sleep efficiency was accounted for by CCU sound levels and noise-induced subjective stress, respectively. Thirty-eight percent (p less than .001) of the variance in Rapid Eye Movement sleep was accounted for by CCU sound levels.
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School of Nursing, University of Colorado, Denver.
D000328:Adult; D005260:Female; D006760:Hospitalization; D006801:Humans; D007362:Intensive Care Units; D009622:Noise / Q000009:adverse effects*; D012893:Sleep Wake Disorders / Q000209:etiology*; D013315:Stress, Psychological