Light-Intensity Physical Activity Is Associated With Insulin Resistance in Elderly Japanese Women Independent of Moderate- to Vigorous-Intensity Physical Activity

Background: It is unclear whether light physical activity is beneficially associated with insulin resistance, similar to moderate and/or vigorous physical activity. This cross-sectional study was performed to determine the relationship between the amount of light physical activity, as determined with a triaxial accelerometer, and insulin resistance. Methods: A total of 807 healthy men and women participated in this study. Physical activity was measured using a triaxial accelerometer worn for 28 days and summarized as light intensity (1.1-2.9 METs) or moderate to vigorous intensity (>= 3.0 METs). Insulin resistance was evaluated by HOMA_R (FPG [mg/dL] x IRI [mu U/mL]/405). Results: The daily time spent in light physical activity was inversely associated with HOMA_R (r = 0.173, P < 0.05). After adjustment for confounders, the association between light physical activity and HOMA_R remained statistically significant (beta = -0.119, P < .05). Light physical activity remained significantly associated with HOMA_R following further adjustment for moderate to vigorous intensity activity (beta = -0.125, P < .05). Similar results were observed when light physical activity was modeled as quartiles, especially in elderly women. Conclusions: These cross-sectional data suggest that light-intensity physical activity is beneficially associated with insulin resistance in elderly Japanese women.