Chronotype Variability and Patterns of Light Exposure of a Large Cohort of United States Residents
Chronotype Variability and Patterns of Light Exposure of a Large Cohort of United States Residents
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发表时间：
2019-06
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通讯作者：
R. Refinetti
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作者：
R. Refinetti
时间类型（即，倾向于在一天中的早或晚的活动）传统上用问卷来测量。还使用体动记录仪进行了一些小样本量的研究。在本研究中，对1887名美国居民的日常活动模式进行了分析，这些居民佩戴了一整周的活动记录仪。这些设备还记录了参与者暴露在光线下的情况。如余弦分析所确定的，平均模式的走动活动表现出强大的24小时振荡，峰值在14：48。平均而言，参与者在午夜前2分钟入睡，并在07：43醒来。时间类型（定义为睡眠的中点）的平均分布为03：50，95%的时间类型在01：00和07：00之间。暴露于明亮日光的平均持续时间为每天3.57小时。每日暴露于强光的持续时间与时间型中度但显著相关（r = -0.18）。光照节律的峰值相位与时间型（r = 0.27）和活动节律的峰值相位（r = 0.36）呈显著相关。时间型不随季节而变化，但暴露于强光下的时间在夏季和春季比冬季和秋季长。这些结果证实了小样本活动记录研究的结果，证实了它们与问卷研究结果的等效性，并证实和扩展了以前的观察结果，即城市居民每天暴露于阳光的时间有限。
Chronotype (i.e., disposition for activity early or late in the day) has traditionally been measured with questionnaires. A few studies with small sample sizes have also been conducted using actigraphy devices. In the present study, analysis was conducted of the daily pattern of activity of 1887 United States residents who wore actigraphy devices for a whole week. The devices also recorded the participants’ exposure to light. As determined by cosinor analysis, the mean pattern of ambulatory activity exhibited robust 24-hour oscillation with a peak at 14:48. On average, participants went to sleep 2 minutes before midnight and woke up at 07:43. The distribution of chronotypes (defined as the midpoint of sleep) had a mean of 03:50, and 95% of all chronotypes were between 01:00 and 07:00. The mean duration of exposure to bright daylight was 3.57 hours per day. Duration of daily exposure to bright light was moderately but significantly correlated with chronotype (r = -0.18). The acrophase of the rhythm of exposure to bright light was significantly correlated with chronotype (r = 0.27) and with the acrophase of the activity rhythm (r = 0.36). Chronotype did not vary with the seasons, but exposure to bright light was longer in summer and spring than in winter and fall. These results confirmed chronotype findings from actigraphic studies with smaller sample sizes, endorsed their equivalence to the results of questionnaire studies, and confirmed and extended previous observations that urban dwellers have limited daily exposure to sunlight.