Fran and Lawrence Bloomberg Department of Obstetrics and Gynecology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
Chronobiol Int. 2013 Oct;30(8):951-62. doi: 10.3109/07420528.2013.789894. Epub 2013 Jul 8.
Circadian phase resetting is sensitive to visual short wavelengths (450-480 nm). Selectively filtering this range of wavelengths may reduce circadian misalignment and sleep impairment during irregular light-dark schedules associated with shiftwork. We examined the effects of filtering short wavelengths (<480 nm) during night shifts on sleep and performance in nine nurses (five females and four males; mean age ± SD: 31.3 ± 4.6 yrs). Participants were randomized to receive filtered light (intervention) or standard indoor light (baseline) on night shifts. Nighttime sleep after two night shifts and daytime sleep in between two night shifts was assessed by polysomnography (PSG). In addition, salivary melatonin levels and alertness were assessed every 2 h on the first night shift of each study period and on the middle night of a run of three night shifts in each study period. Sleep and performance under baseline and intervention conditions were compared with daytime performance on the seventh day shift, and nighttime sleep following the seventh daytime shift (comparator). On the baseline night PSG, total sleep time (TST) (p < 0.01) and sleep efficiency (p = 0.01) were significantly decreased and intervening wake times (wake after sleep onset [WASO]) (p = 0.04) were significantly increased in relation to the comparator night sleep. In contrast, under intervention, TST was increased by a mean of 40 min compared with baseline, WASO was reduced and sleep efficiency was increased to levels similar to the comparator night. Daytime sleep was significantly impaired under both baseline and intervention conditions. Salivary melatonin levels were significantly higher on the first (p < 0.05) and middle (p < 0.01) night shifts under intervention compared with baseline. Subjective sleepiness increased throughout the night under both conditions (p < 0.01). However, reaction time and throughput on vigilance tests were similar to daytime performance under intervention but impaired under baseline on the first night shift. By the middle night shift, the difference in performance was no longer significant between day shift and either of the two night shift conditions, suggesting some adaptation to the night shift had occurred under baseline conditions. These results suggest that both daytime and nighttime sleep are adversely affected in rotating-shift workers and that filtering short wavelengths may be an approach to reduce sleep disruption and improve performance in rotating-shift workers.
昼夜节律相位重置对视觉短波长（450-480nm）敏感。选择性过滤这个波长范围可能会减少与轮班工作相关的不规律的光-暗时间表引起的昼夜节律失调和睡眠障碍。我们研究了在夜班期间过滤短波长（<480nm）对 9 名护士（5 名女性和 4 名男性；平均年龄±标准差：31.3±4.6 岁）的睡眠和表现的影响。参与者被随机分配在夜班期间接受过滤光（干预）或标准室内光（基线）。通过多导睡眠图（PSG）评估两个夜班后的夜间睡眠和两个夜班之间的日间睡眠。此外，在每个研究期间的第一个夜班的每 2 小时以及每个研究期间的三个夜班的中间夜测量唾液褪黑素水平和警觉性。将基线和干预条件下的睡眠和表现与第七个白班的日间表现以及第七个白天班次后的夜间睡眠（对照）进行比较。在基线夜 PSG 中，总睡眠时间（TST）（p<0.01）和睡眠效率（p=0.01）显著降低，入睡后醒来时间（WASO）（p=0.04）显著增加与对照夜睡眠相比。相比之下，在干预下，TST 比基线增加了平均 40 分钟，WASO 减少，睡眠效率增加到与对照夜相似的水平。在基线和干预条件下，日间睡眠均显著受损。与基线相比，干预下第一个（p<0.05）和中间（p<0.01）夜的唾液褪黑素水平显著升高。在两种情况下，整个夜间的主观困倦感均增加（p<0.01）。然而，警觉性测试的反应时间和吞吐量在干预下与日间表现相似，但在第一个夜班的基线下受损。到中间夜班时，日间班次和两个夜班条件之间的表现差异不再显著，这表明在基线条件下已经对夜班进行了一些适应。这些结果表明，轮班工作者的日间和夜间睡眠均受到不利影响，过滤短波长可能是减少轮班工作者睡眠中断和提高表现的一种方法。
