Institute of Physiology, Komi Science Centre, Ural Branch of Russian Academy of Science, Syktyvkar, Russia.
Chronobiol Int. 2010 Jul;27(6):1259-70. doi: 10.3109/07420528.2010.487624.
Residing at northern latitudes for long periods of time is associated with sleep disturbances and internal desynchronization, which are considered to be causes of chronic diseases in old age. In children and teenagers, they result in a poor school achievement, psychological problems, and increase in consumption of stimulants. In this paper, we analyze the relationship between both chronotype and sleep length and the variables of age, sex, place of residence, type of settlement (village/city), latitude and longitude of residence, and school achievement of young inhabitants of northern European Russia. We surveyed 1101 children and teenagers between 11 to 23 yrs of age living in four settlements located between 59 degrees and 67 degrees North latitude and 33 degrees and 60 degrees East longitude. The Munich chronotype questionnaire (MCTQ) was used in the study, and all participants were also required to answer a question about their school achievements. An analysis of covariance (ANCOVA) was used to assess the influence of the analyzed factors on sleep length and chronotype. Self-reported sleep length of teenagers depended moderately on age, whereas the place of residence, latitude, and type of settlement only had a weak effect. Chronotype strongly depended on place of residence and longitude; it moderately depended on latitude and age; and it weakly depended on sex and type of settlement. The sleep length of village teenagers was 46 min longer than that of urban teenagers. The authors found a 1 h and 18 min phase delay of the sleep-wake rhythm (as a marker of chronotype) in teenagers moving in the East-West direction and a 16-min delay moving in the South-North direction within one time zone. There was a weak, but significant, positive correlation between chronotype and time of sunrise. There was about a 2-fold stronger influence of chronotype than sleep length on achievement of school children and college students. We conclude that socioeconomic factors exert a significant influence on sleep length and that climatic conditions exert a significant influence on the chronotype of teenagers in the northern latitudes.
长期居住在高纬度地区会导致睡眠障碍和内部时间失调，这些被认为是老年慢性疾病的成因。在儿童和青少年中，它们会导致学业成绩不佳、心理问题，并增加兴奋剂的消耗。在本文中，我们分析了两种类型的睡眠长度和变量之间的关系，包括年龄、性别、居住地、居住地的类型（村庄/城市）、纬度和经度，以及北欧俄罗斯年轻居民的学业成绩。我们调查了 1101 名年龄在 11 至 23 岁之间的儿童和青少年，他们居住在四个位于北纬 59 度至 67 度和东经 33 度至 60 度之间的定居点。研究使用了慕尼黑时间类型问卷（MCTQ），所有参与者还被要求回答一个关于他们学业成绩的问题。采用协方差分析（ANCOVA）来评估分析因素对睡眠长度和时间类型的影响。青少年的自我报告睡眠时间与年龄中度相关，而居住地、纬度和居住地类型只有微弱影响。时间类型强烈依赖于居住地和经度；中度依赖于纬度和年龄；弱度依赖于性别和居住地类型。村庄青少年的睡眠时间比城市青少年长 46 分钟。作者发现，在一个时区内向东西方向移动的青少年的睡眠-觉醒节律（作为时间类型的标志）相位延迟了 1 小时 18 分钟，而在南北方向移动的青少年则延迟了 16 分钟。时间类型与日出时间之间存在微弱但显著的正相关。时间类型对中小学生成绩的影响比睡眠时间略强，但仍有明显影响。我们得出结论，社会经济因素对睡眠长度有显著影响，气候条件对高纬度地区青少年的时间类型有显著影响。
