OBJECTIVELY MEASURED MODERATE AND VIGOROUS INTENSITY PHYSICAL ACTIVITY BUT NOT SEDENTARY TIME PREDICTS INSULIN RESISTANCE IN HIGH RISK INDIVIDUALS

Abstract

Objective - Low levels of physical activity (PA) appear to be associated with insulin resistance (IR). However, the detailed associations of these complex relationships remain elusive. We examined the prospective associations between self-reported TV-viewing time, objectively measured time spent sedentary, at light (LPA), and moderate and vigorous intensity physical activity (MVPA) with IR.

Research design and methods - In 192 individuals (81 men, 111 women) with a family history of type 2 diabetes we measured PA, anthropometric and metabolic variables at baseline and after 1 year of follow-up in the ProActive UK trail. Physical activity was measured objectively by accelerometry. IR was expressed as fasting insulin and the homeostasis model assessment score (HOMA).

Results - Baseline MVPA was a significant predictor of fasting insulin at follow-up (β=−0.004, 95% CI;−0.007;−0.0001, P=0.022), and the association approached significance for HOMA-IR (β=−0.003, 95% CI;−0.007; 0.000002, P=0.052), independent of time spent sedentary, at light intensity activity, sex, age, smoking status, waist circumference and self-reported TV viewing. Time spent sedentary and at LPA were not significantly associated with IR. Change in MVPA between baseline and follow-up was inversely related to fasting insulin (β=−0.003, 95% CI;−0.007;−0.0003, P=0.032) and the HOMA score (β=−0.004, 95% CI;−0.008;−0.001, P=0.015) at follow-up, after adjusting for baseline phenotype in addition to the same confounders as above.

Conclusion - These results highlight the importance of promoting moderate intensity activity such as brisk walking for improving insulin sensitivity and possibly other metabolic risk factors to prevent type 2 diabetes.