RESUMO
<p><b>OBJECTIVE</b>To study the adverse effects of sleep problems and sleep insufficiency on attention in class and pupils' acadamic achievements.</p><p><b>METHODS</b>A total of 1138 students from four primary schools at ages of 6-12 years were randomly sampled from four districts of Changsha city, Hunan Province June 2009 to April 2010. The inquired items included sleep problems, sleep time, sleep quality, attention in class and academic achievements. Teachers and parents observed the pupils according to the unified requirements for 3 months and then filled out the questionnaires.</p><p><b>RESULTS</b>The total valid inquiry tables were 1091 with the answering rate of 95.87%, including 549 boys and 542 girls. The sleep quality was more poor in children with sleep problems or sleep insufficiency than in children with normal sleep. The sleep quality was reduced and aggravated along with the increasing sleep problems and the reducing sleep time. The attention in class and academic achievements in children with sleep problems or sleep insufficiency were more poor than in children with normal sleep. The sleep quality index was negatively correlated with attention in class and academic achievements. The attention in class was positively correlated with academic achievements.</p><p><b>CONCLUSIONS</b>The decline in sleep quality directly affects the attention in class and reduce the academic achievements in primary school children.</p>