Benloucif S, Green K, L'Hermite-Balériaux M, Weintraub S, Wolfe L F, Zee P C
Department of Neurology, Abbott Hall, 11th flr, Northwestern University Feinberg School of Medicine, 710 N. Lake Shore Drive, Chicago, IL 60611, USA.
Neurobiol Aging. 2006 Dec;27(12):1870-9. doi: 10.1016/j.neurobiolaging.2005.10.011. Epub 2005 Nov 23.
The present study assessed whether advances in sleep times and circadian phase in older adults might be due to decreased responsiveness of the aging circadian clock to light. Sixteen young (29.3+/-5.6 years) and 14 older adults (67.1+/-7.4 years) were exposed to 4h of control dim (10lux) or bright light (3500lux) during the night. Phase shifts of the melatonin rhythm were assessed from the nights before and after the light exposure. Bright light delayed the melatonin midpoint in both young and older adults (p<0.001). Phase delays for the older subjects were not significantly different from those of the young subjects for either the bright or dim light conditions. The magnitude of phase delays was correlated with both sleep offset and phase angle in the older, but not the younger subjects. The present results indicate that at light intensities commonly used in research as well as clinical practice older adults are able to phase delay to the same extent as younger subjects.
本研究评估了老年人睡眠时间和昼夜节律相位的提前是否可能是由于衰老的生物钟对光的反应性降低所致。16名年轻人（29.3±5.6岁）和14名老年人（67.1±7.4岁）在夜间接受4小时的对照暗光（10勒克斯）或强光（3500勒克斯）照射。从光照前后的夜晚评估褪黑素节律的相位变化。强光使年轻人和老年人的褪黑素中点均延迟（p<0.001）。在强光或暗光条件下，老年受试者的相位延迟与年轻受试者的相位延迟无显著差异。在老年受试者中，相位延迟的幅度与睡眠偏移和相位角均相关，但在年轻受试者中并非如此。目前的结果表明，在研究和临床实践中常用的光照强度下，老年人能够与年轻受试者一样程度地延迟相位。
