Abstract: Objective To analyze the current situation of negative affect among junior high school students in Beijing and its association with physical activity, so as to provide evidence for improving students' negative affect and promoting their mental health. Methods Using stratified multistage cluster sampling, a self-administered questionnaire survey was conducted among 12 338 students from 63 junior high schools in 18 counties/districts of Beijing from March to May in 2014.The prevalence of negative affect and its association with physical activity were analyzed. Results In the past 12 months, 1 517 (12.30%) students often/always felt lonely, 3 337 (27.05%) students often/always felt unhappy due to academic pressure or performance problems, 1 514 (12.27%) students often/ always had insomnia because of worrying about something, and 1 354 (10.97%) students stopped their usual activities because of sadness and despair for 2 weeks or more.The trend χ² test showed that the increased frequency of physical activity was closely associated with the decrease of self-reported negative affect.After adjusting for sex, area, school type, grade and academic performance, the Log-binomial models showed that students who were physically active for 60 minutes or more generally had a lower risk of negative affect compared with those who were never physically active for 1 week.And having physical activity for 3 days or more weekly could significantly reduce the risk of all four kinds of negative affect, especially for those students with loneliness.When stratified by sex, area, school type, grade or academic performance, the associations between physical activity and one or more negative affect were observed in varying degrees at almost all subgroups excepted for students at the ninth grade. Conclusions The junior high school students in Beijing have relatively high prevalence of negative affect.Actively participating in physical activity for more than 3 days per week helps to improve the mental health for most students, and has the most significant effect on loneliness.

Key words: negative affect, physical activity, junior high school students

摘要： 目的 分析北京市初中生负性情绪流行现况,及其与身体活动的关系,为改善学生负性情绪,促进学生心理健康提供科学依据。 方法 于2014年3-5月,采用分层整群随机抽样方法对北京市18个区县63所中学的12 338名初中生进行负性情绪及身体活动情况调查,分析北京市初中生负性情绪流行现况及其与身体活动的关系。 结果 1 517名(12.30%)学生在过去12个月里经常/总是感到孤独,3 337名(27.05%)学生经常/总是因为学习压力或成绩问题感到心情不愉快,1 514名(12.27%)学生经常/总是因为担心某事而失眠,1 354名(10.97%)学生曾连续2周或更长时间因为伤心绝望而停止平常的活动。单因素分析发现,身体活动频率增加与负性情绪报告率下降关系密切。控制性别、地区、学校类型、年级和学习成绩后,Log-binomial模型结果显示,与1周内从不进行身体活动的学生相比,进行过60 min以上身体活动的学生出现负性情绪的风险普遍较低,进行3 d及以上的身体活动可降低4种负性情绪发生的风险,其中对学生孤独感的改善作用最为显著。分层分析结果显示,除初三年级学生外,在不同性别、地区、学校类型、年级和学习成绩的学生中,身体活动对一种或多种负性情绪有不同程度的改善作用。 结论 北京市初中生负性情绪流行率相对较高,每周积极参与3 d以上身体活动有助于改善大部分学生群体的负性情绪,且对孤独感的改善作用最为明显。

关键词: 负性情绪, 身体活动, 初中生