Post-meal exercise under ecological conditions improves post-prandial glucose levels but not 24-hour glucose control

Abstract

We investigated whether post-meal walking (PMW) improved post-prandial glucose and 24h glucose control under free-living conditions among physically inactive young women.

Methods: Young women (Age: 20±1years; percent body fat: 28.2 ± 12%; BMI: 23.8 ± 4.2kg·m-1) completed a randomised crossover study to assess if PMW confers benefit. On the PMW day, women completed three bouts of brisk walks, and on the Control day they were instructed to follow normal habitual activities. Continuous glucose monitors captured post-prandial and 24h glucose, and physical activity monitors tracked physical activity throughout the study.

Results: PMW walking increased total daily step count (Control = 9,159 ± 2,962 steps vs. PMW = 14,611±3,891 steps, p<0.001) and activity scores (Control=33.87±1.16 METs·h vs. PMW = 36.11±1.58 METs·h, p < 0.001). PMW led to lower 3h average post-prandial glucose (main effect of condition, p=0.011) and 3h post-prandial area under curve glucose responses (main effect of condition, p = 0.027) compared to the control condition. Post hoc analysis revealed the largest decline occurred after dinner (3h average glucose Control = 7.55±1.21 mmol/L vs. PMW = 6.71 ± 0.80mmol/L, p = 0.039), when insulin sensitivity is typically diminished. Despite improvements in post-prandial glucose control, this did not translate to improvements in 24h glucose control (p > 0.05).

Conclusion: Physically inactive and metabolically healthy young women, PMW improves post-prandial glucose but not 24h glucose control.

Keywords: Glucose control; continuous glucose monitoring; post meal walking.

Figure 1-

Post-meal walking (PMW) led to a main effect of condition in post-prandial 3h average glucose and 3h area under the curve (AUC) following breakfast, lunch, and dinner (for both main effect of condition, p<0.05). Post hoc analysis found that post-prandial 3h average glucose was significantly lower after dinner following PMW compared to dinner on the control day. p=0.039 vs. Control Dinner.

Figure 2-

3h post-prandial glucose response following breakfast (top), lunch (middle), and dinner (bottom) during the control day (open circles) and post-meal walking (PMW) day (closed squares). The black rectangle represents the 15-minute PMW period completed by participants during the PMW day only.