729-P: Post-Breakfast Physical Activity Is Most Optimal for Improving Postprandial Glycemic Control in Healthy Adults

Purposeful and deliberate exercise improves postprandial glucose control. However, there is less information concerning the effects of simple physical activities (standing, walking, circuit exercise) that can easily be integrated into a person’s day. Furthermore, the optimal timing between such an activity and a meal that elicits the most optimal glucose control is completely unknown. Three groups of 16 healthy adults volunteered to participate in three separate interventions: Stand (30-minutes standing still; RPE = 6±1), Walk (30-min treadmill walk at a self-selected brisk pace; RPE = 11±2, 5.6±0.8 kph), and Circuit (three sets of 10 squats, 10 push-ups, 10 lunges, 10 sit-ups; RPE = 11±2, 7.1±1.8 minutes to complete). In each intervention, participants completed four trials during which they drank a mixed-nutrient breakfast shake containing 500 kcals. Interstitial glucose responses were measured by continuous glucose monitoring (Dexcom G5). Postprandial glucose tolerance was quantified during the 2-hours period after meal ingestion. In each trial, the physical activity was completed either 2-hours after (trial A; control), immediately before (trial B), immediate after (trial C), or 30-minutes after (trial D) the meal. While trials B and D showed some improvement in postprandial glucose control compared to trial A, this was not statistically significant. Trial C, however, showed a significant improvement in mean glucose, standard deviation for glucose, and the area under the glucose curve in all three interventions (P<0.05), when compared to trial A. Energy intake (diet records) and energy expenditure (Actigraph) were consistent throughout the studies and did not influence the findings.

In conclusion, low to moderate-intensity physical activity (either standing, walking, or body-weight circuit exercise) is best implemented soon after a meal to induce the greatest improvement in blood glucose control, in young healthy adults.