Resistance exercise after high-carb meal improves postprandial glucose and endothelial function in healthy adults

Postprandial hyperglycaemia is characterized by elevated blood glucose levels following a meal and is associated with impaired vascular endothelial function. Regular exercise has been shown to preserve and improve vascular endothelial function. However, whether there is an optimal time to exercise to mitigate postprandial hyperglycaemia-related vascular dysfunction is unknown. This randomized crossover study recruited healthy adults to compare four exercise timing conditions with a non-exercise Control. Participants performed whole-body resistance exercises at one of 30 min pre (30Pre), immediately post (IP), 30 min post (30Post), or 60 min post (60Post) consuming a high carbohydrate meal. Measures of blood glucose and endothelial function (via flow-mediated dilation of the brachial artery) were assessed at fasting and incrementally to 120 min following the meal. Exercise performed IP improved flow-mediated dilation by 2.3 ± 2.7% (P = 0.04) and lowered postprandial glucose by 1.5 ± 1.8 mmol/L (P < 0.01) at 1 h postprandially, compared to the Control. 30Post and 60post significantly decreased glucose post exercise by 1.06 ± 2.26 mmol/L (P = 0.002) compared to the control. Comparatively, pre-meal exercise did not improve postprandial vascular function or glucose compared to the control or other timing conditions. These findings add precision to the existing literature on postprandial exercise by identifying immediately after eating as most effective for improving vascular and metabolic outcomes relevant to cardiometabolic disease prevention.