Alterations In Glycemic Variability, Vascular Health, And Oxidative Stress Following A 12-Week Aerobic Exercise Intervention

The state of being overweight or obese leads to an increased risk of development of cardiometabolic disease. Increases in glycemic variability have been associated with greater induction of oxidative stress and declined vascular health, which may be exacerbated by higher weight status and improved through exercise. PURPOSE: To examine the impact of a 12-week aerobic exercise intervention on continuous glucose monitor (CGM) assessed glucose concentrations and glycemic variability, and biological markers of vascular health and oxidative stress in non-diabetic overweight or obese adults. METHODS: Eight adults (BMI = 29.4 ± 8.3 kg/m2; age = 48.9 ± 5.2 years; mean ± SD) completed a 12-week aerobic exercise intervention. Participants walked 3 times per week at moderate intensity and expended 10-12 kilocalories per kilogram of body weight each week. Body weight and V̇O2max were measured, and a fasting blood sample was collected at pre- and post-intervention. Participants also wore a CGM, which determined interstitial glucose concentrations every 5 minutes, for 7 consecutive days at pre- and post-intervention. Glycemic variability was calculated using CGM-assessed glucose concentrations over the 7 days. Fasting biological markers of vascular health and vasodilation, nitric oxide (NO), as well as oxidative stress and vasoconstriction, myeloperoxidase (MPO), were measured, and the vasodilation:vasoconstriction (NO:MPO) ratio was calculated. RESULTS: No glucose concentrations or measures of glycemic variability changed from pre- to post-intervention, while MPO concentration decreased (24.8 ± 8.2 ng/mL to 16.4 ± 4.6 ng/mL, p < 0.01) and the NO:MPO ratio increased (3.5:1 to 6.4:1, p < 0.01) following the 12-week intervention. Although body weight and V̇O2max did not change in the overall sample from pre- to post-intervention, individual changes in body weight and V̇O2max were observed. CONCLUSIONS: Twelve weeks of aerobic exercise reduced oxidative stress and improved the propensity to vasodilate but did not alter CGM-assessed glucose concentrations or glycemic variability in this group of overweight or obese non-diabetic adults. These findings may be due to individual changes in body weight or V̇O2max, which necessitates further research to explore their influence on these outcomes of interest.