Association between Objectively Measured Sedentary Behaviour and Sleep Quality in Japanese Adults: A Population-Based Cross-Sectional Study

The association between sedentary behaviour and sleep quality (SQ) remains unclear, partly due to the limited methodology for assessing sedentary time and the influence of obesity. This study aimed to examine the association between objectively measured sedentary time and poor SQ, as well as the association of visceral fat accumulation. This cross-sectional study used health check-up data obtained from 721 Japanese adults. Sedentary time and physical activity were measured using an accelerometer for ≥7 days, with ≥10 measurement hours per day. Poor SQ was determined by a Pittsburgh Sleep Quality Index score of ≥ 6. Visceral fat was measured using the abdominal bioimpedance method. A logistic regression model was used to analyse the association between sedentary time and SQ. We found that higher sedentary time was associated with poorer SQ. This association remained significant after adjustment for several covariates, including visceral fat. Compared with the lowest tertile of sedentary time, the second and highest tertile had a significantly higher OR of poor SQ (Tertile 2: OR = 2.06 [95% CI 1.14,3,73]; Tertile 3: OR = 2.76 [95% CI 1.49, 5.11]). These results suggest that managing sedentary time itself might contribute to improving SQ.