中国青少年的睡眠质量与身体素质：多层次横断面研究

Background Sleep quality is an important component of adolescent health, but its association with physical fitness remains insufficiently understood. This study examined the association between sleep quality and physical fitness among Chinese adolescents. Methods This school-based cross-sectional study included 5,018 adolescents from 18 schools in six Chinese cities. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The Physical Fitness Index (PFI) was the primary outcome, and estimated VO₂max was the secondary outcome. School-level random-intercept models adjusted fo