Lifestyle Behaviors from Early Childhood to Junior High School in Rural Japan: A Cross-sectional Study

Background Understanding combinations of lifestyle behaviors, including screen time, outdoor activity, and sleep, is essential for promoting children’s health. However, evidence spanning multiple developmental stages within the same community remains limited, particularly in rural areas of Japan. Methods This cross-sectional study examined school stage and sex differences in lifestyle behaviors among children living in a rural region of southern Japan. Participants included 1,192 children from early childhood through junior high school (49.8% girls, 50.2% boys). Information on sleep timing, sleep duration, outdoor activity time, and screen time was collected using parent- and self-reported questionnaires. Differences by grade and sex were analyzed using two-way analysis of variance and chi-square tests. Results Across all school stage, average sleep duration fell below age-specific recommendations, with progressively later bedtimes and shorter sleep duration evident from early childhood onward. Screen time increased steadily across school stages, suggesting the early establishment and consolidation of screen-related behaviors. Outdoor time was below recommended levels among girls and children in lower elementary grades (Grades 1–3), and sex differences became increasingly apparent during the elementary grades (Grades 4–6). Collectively, these findings indicate that insufficient sleep, inadequate physical activity, and escalating screen exposure may originate early in life and intensify throughout childhood, underscoring the need for early preventive interventions. Conclusions: Unhealthy lifestyle behaviors related to sleep, physical activity, and screen use were observed across multiple developmental stages within a single rural community. These findings underscore the importance of a life-course approach and highlight the need for early, developmentally appropriate public health strategies to support healthier daily routines among children in rural regions.