Walking Initiated 20 Minutes before the Time of Individual Postprandial Glucose Peak Reduces the Glucose Response in Young Men with Overweight or Obesity: A Randomized Crossover Study

Abstract

ABSTRACT Background Although a single bout of postmeal exercise can lower postprandial glucose (PPG), its optimal timing remains unclear. Objective This study aimed to investigate the effect of exercise timing using an individualized approach on PPG in overweight or obese young men. Methods Twenty men [age: 23.0 ± 4.3 y; BMI (kg/m2): 27.4 ± 2.8] each completed three 240-min trials in a randomized order separated by 6–14 d: 1) sitting (SIT), 2) walking initiated at each participant's PPG-peak time (PPGP) (iP), and 3) walking initiated 20 min before the PPGP (20iP). For each participant, PPGP was predetermined using continuous glucose monitoring. Walking was performed at 50% maximal oxygen consumption for 30 min. Venous blood was collected at 15- and 30-min intervals for 0–120 min and 120–240 min, respectively. The primary outcome was plasma PPG. Generalized estimating equations were used for comparison between trials. Results Compared with SIT, the 4-h incremental AUCs (iAUCs) for plasma PPG (−0.6 mmol · L−1 · h; P = 0.047) and insulin (−28.7%, P < 0.001) were reduced in 20iP only, and C-peptide concentrations were lower after iP (−14.9%, P = 0.001) and 20iP (−28.7%, P < 0.001). Plasma insulin (−11.1%, P = 0.006) and C-peptide (−8.3%, P = 0.012) were lower due to the 20iP compared with iP treatment. Finally, PPG reductions due to iP and 20iP occurred only in men with a BMI > 27.5 kg/m2 (iP, −11.2%; 20iP, −14.7%; P = 0.047) and higher glucose iAUC values during SIT (iP, −25.5%; 20iP, −25.7%; P < 0.001). Conclusions Walking initiated 20 min before PPGP lowered PPG and plasma insulin and C-peptide concentrations in young men with overweight or obesity, in particular in those with high BMI or glucose iAUC values during SIT; it also lowered plasma insulin and C-peptide concentrations more effectively than did exercise initiated at PPGP. This trial was registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx) as ChiCTR1900023175.