Dose–response association of physical activity with HbA1c: Intensity and bout length

•MVPA is associated with lower HbA1c among adults at risk for type 2 diabetes.•The association is curvilinear, with a stronger correlation at lower doses of PA.•The relationship is more pronounced for short bouts (< 10 min) of activity.

ObjectiveThe aims of this study were to characterize the dose–response relationship between moderate-to-vigorous intensity physical activity (MVPA), and light-intensity activity with HbA1c in adults at low, moderate, and high risks of type 2 diabetes, and to compare the relationship of short (1 to 9 min) versus long (10 + min) bouts of MVPA with HbA1c.MethodsData from 2707 participants from the 2003–2006 National Health And Nutrition Examination Survey were analyzed in 2014–2015. Type 2 diabetes risk was classified into three groups based upon age (< 40 years; ≥ 40 years) and BMI (< 30; ≥ 30). The relationship between HbA1c and accelerometer-based physical activity variables was assessed using multiple regression models.ResultsThere was a curvilinear dose–response relationship between HbA1c with total activity and MVPA in adults at moderate or high risk for type 2 diabetes: higher amounts of physical activity were associated with lower HbA1c. The association of physical activity on HbA1c was stronger at lower levels of physical activity. There was no dose–response relationship in adults at low risk for type 2 diabetes. The relationship between short bouts with HbA1c was stronger than for bouts ≥ 10 min.ConclusionsIn adults at risk for type 2 diabetes, there is a dose–response relationship between physical activity and HbA1c levels such that the relationship: (1) is curvilinear; (2) is stronger when a higher percent of total activity comes from MVPA; and (3) is more potent with short bouts of MVPA. Fractionalized physical activity of at least moderate-intensity may contribute to long-term glucose control.