Prospectively Reallocating Sedentary Time: Associations with Cardiometabolic Health.

Purpose: This study aimed to investigate whether prospectively reallocating time away from sedentary behavior (SB) into different physical activity intensities is associated with 12-month change to cardiometabolic health in a cohort at high risk of type 2 diabetes (T2DM).
Methods: Participants with known risk factors for T2DM were recruited from primary care (Leicestershire, United Kingdom) as part of the Walking Away from Type 2 Diabetes trial (n = 808). Participants were followed up at 12, 24, and 36 months. SB, light-intensity physical activity (LPA) and moderate-to-vigorous intensity physical activity (MVPA) were measured objectively by accelerometer. Postchallenge glucose, triglycerides, HDL cholesterol, systolic blood pressure, and waist circumference were analyzed individually and combined into a clustered cardiometabolic risk score (CMRS). Associations of changing SB over each consecutive 12-month period were analyzed taking account of repeated measures.
Results: Reallocating 30 min from SB to LPA was associated with 0.21-cm (95% confidence interval, 0.03-0.38 cm) reduction in waist circumference, 0.09-mmol·L (0.04-0.13 mmol·L) reduction in 2-h glucose, 0.02-mmol·L (0.00-0.04 mmol·L) reduction in triglycerides, and 0.02 (0.01-0.03) reduction in CMRS. Every 30-min reallocation from SB to MVPA was associated with 1.23-cm (0.68-1.79 cm) reduction in waist circumference, 0.23-mmol·L (0.10-0.36 mmol·L) reduction in 2-h glucose, 0.04-mmol·L (0.00-0.09 mmol·L) reduction in triglycerides, and 0.07 (0.04-0.11) reduction in CMRS. Reallocating 30 min from LPA into MVPA was also associated with 1.02-cm (0.43-1.60 cm) reduction in waist circumference, 0.16-mmol·L (0.02-0.30 mmol·L) reduction in 2-h glucose, and 0.05 (0.01-0.09) reduction in CMRS.
Conclusion: Over 12 months, reallocating time away from SB into LPA or MVPA was associated with improved cardiometabolic health in a population at risk of T2DM, with the greatest benefits observed for MVPA.