Effects of Postmeal Walking on Postprandial Glucose Control and Oxidative Stress

Abstract

Postprandial hyperglycemia can increase levels of oxidative stress and is an independent risk factor for complications associated with type 2 diabetes. PURPOSE: To evaluate the acute effects of a 15-minute postmeal walk on glucose control and markers of oxidative stress following a high-carbohydrate meal. METHODS: Ten obese subjects (55.0 ± 10.0 yrs) with impaired fasting glucose (107.1 ± 9.0 mg/dL) participated in this repeated measures trial. All subjects underwent three conditions: 1) Test meal with no walking or fiber (CONTROL), 2) Test meal with 10g fiber and no walking (FIBER), 3) Test meal with no fiber followed by a 15-min treadmill walk at preferred walking speed (WALK). Blood samples were taken over four hours. A repeated measures ANOVA was used to compare all outcome variables. RESULTS: The 2hr and 4hr iAUC for glucose was lower in both FIBER (2hr: -93.59 mmol·120 min·L-1, p= 0.006; 4hr: -92.59 mmol·240 min·L-1; p= 0.041) and WALK (2hr: -77.21 mmol·120 min·L-1, p= 0.002; 4hr: -102.94 mmol·240 min·L-1; p= 0.005) conditions respectively, compared with CONTROL. There were no differences in 2hr or 4hr iAUC for glucose between FIBER and WALK (2hr: p= 0.493; 4hr: p= 0.783). The 2hr iAUC for insulin was significantly lower in both FIBER (-37.15 μU ·h/mL; p= 0.021) and WALK (-66.35 μU ·h/mL; p< 0.001) conditions, compared with CONTROL, and was significantly lower in the WALK (-29.2 μU ·h/mL; p= 0.049) condition, compared with FIBER. The 4hr iAUC for insulin in the WALK condition was significantly lower than both CONTROL (-104.51 μU ·h/mL; p= 0.001) and FIBER (-77.12 μU ·h/mL; p= 0.006) conditions. Markers of oxidative stress were not significantly different between conditions. CONCLUSIONS: A moderate 15-minute postmeal walk is an effective strategy to reduce postprandial hyperglycemia. However, it is unclear if this attenuation leads to improvements in postprandial oxidative stress.