Barroggi Constantino Débora, Lederle Katharina A, Middleton Benita, Revell Victoria L, Sletten Tracey L, Williams Peter, Skene Debra J, van der Veen Daan R
Chronobiology Section, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
Geroscience. 2025 Jan 17. doi: 10.1007/s11357-025-01506-y.
Low indoor light in urban housing can disrupt health and wellbeing, especially in older adults who experience reduced light sensitivity and sleep/circadian disruptions with natural aging. While controlled studies suggest that enhancing indoor lighting may alleviate the negative effects of reduced light sensitivity, evidence for this to be effective in the real world is lacking. This study investigates the effects of two light conditions on actigraphic rest-activity rhythms and subjective sleep in healthy older adults (≥ 60 years) living at home. Two photon-matched lights were compared; a control white light (4000 K) and a blue-enriched white light (17000 K) at two different intensities (300-450 lx and 1100-1200 lx respectively). Participants (n = 36, 25 female) completed an 11-week randomized, cross-over study, comprising 1 week of baseline, 3 weeks of self-administered light exposure (2 h in the morning and 2 h in the evening), and 2 weeks of washout for each light condition. Participants completed sleep diaries, wore a wrist actigraph and a light sensor necklace, and collected urine to measure 6-sulphatoxymelatonin. Longer duration of morning blue-enriched light significantly improved rest-activity rhythm stability and decreased sleep fragmentation. More time spent above 2500 lx increased actigraphy amplitude, daytime activity, and advanced bedtime. Evening light exposure, however, increased sleep latency and lowered sleep efficiency. Our findings show morning blue-enriched light is beneficial whereas evening light should be avoided. Optimal timing of self-administered light interventions thus may offer a promising strategy to improve sleep and rest-activity rhythms in older adults in real-world settings.
城市住宅中室内光线昏暗会影响健康和幸福，尤其是对老年人而言，随着自然衰老，他们对光线的敏感度会降低，睡眠/昼夜节律也会受到干扰。虽然对照研究表明增强室内照明可能会减轻光线敏感度降低的负面影响，但缺乏在现实世界中有效的证据。本研究调查了两种光照条件对居家健康老年人（≥60岁）活动记录仪记录的休息-活动节律和主观睡眠的影响。比较了两种光子匹配光；一种是对照白光（4000K）和一种蓝光增强白光（17000K），强度分别为两种不同水平（分别为300 - 450勒克斯和1100 - 1200勒克斯）。参与者（n = 36，25名女性）完成了一项为期11周的随机交叉研究，包括1周的基线期、3周的自我光照暴露（早上2小时和晚上2小时），每种光照条件有2周的洗脱期。参与者完成睡眠日记，佩戴腕部活动记录仪和光传感器项链，并收集尿液以测量6 - 硫酸氧褪黑素。早晨蓝光增强光照射时间越长，显著改善了休息-活动节律稳定性，并减少了睡眠片段化。在2500勒克斯以上花费的时间越多，增加了活动记录仪记录的活动幅度、白天活动量，并使就寝时间提前。然而，晚上光照暴露增加了入睡潜伏期并降低了睡眠效率。我们的研究结果表明，早晨蓝光增强光是有益的，而晚上应避免光照。因此，自我光照干预的最佳时机可能为改善现实环境中老年人的睡眠和休息-活动节律提供一种有前景的策略。
