Effects of a daylight intervention in the morning on circadian rhythms and sleep in geriatric patients: a randomized crossover trial
Abstract
PURPOSE: During hospitalization, circadian rhythms and sleep are often disrupted, which has negative effects on health outcomes. Therefore, we aimed to investigate whether a daylight intervention in the morning could improve the circadian rhythms of cortisol and melatonin and enhance objective and subjective sleep quality in geriatric patients.
METHODS: The present study is a randomized, two-period crossover trial conducted in a geriatric ward in 15 non-demented geriatric trauma patients with a mean age of 83.1 ± 5.4 years. All patients underwent a daylight intervention period, during which they were exposed to a daylight lamp from 8:00 to 13:00 h, and a control period of 6 days each. Cortisol and melatonin levels were measured on day 5 of each period. Objective and subjective sleep quality were assessed using actigraphy and questionnaires, respectively. Within-participant differences between periods were investigated for all parameters.
RESULTS: A trend towards improvement in cortisol and melatonin rhythmicity was found. An increase in mean melatonin levels from 0.3 ± 0.1 to 0.9 ± 0.8 ng/L was observed during the intervention period (p = .063). There was also a trend towards increased sleep efficiency, whereas subjective sleep quality tended to decrease. None of the results were significant.
CONCLUSION: A daylight intervention in the morning led to a positive trend in cortisol and melatonin rhythmicity, whereas no improvement in subjective sleep quality was found.
TRIAL…
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Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.
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