Associations of sedentary time, physical activity, and fitness with muscle glucose uptake in adults with metabolic syndrome

Objective: The objective of the study was to investigate the associations of sedentary time, physical activity, and cardiorespiratory fitness with skeletal muscle glucose uptake (GU).

Methods: Sedentary time and physical activity were measured with accelerometers and VO₂ max with cycle ergometry in 44 sedentary adults with metabolic syndrome. Thigh muscle GU was determined with [¹⁸ F]FDG-PET imaging.

Results: Sedentary time (β = -0.374), standing (β = 0.376), steps (β = 0.351), and VO₂ max (β = 0.598) were associated with muscle GU when adjusted for sex, age, and accelerometer wear time. Adjustment for body fat-% turned all associations non-significant.

Conclusion: Body composition is a more important determinant of muscle GU in this population than sedentary time, physical activity, or fitness.