Consecutive days of exercise decrease insulin response more than a single exercise session in healthy, inactive men.

Abstract

It is reported that a single bout of exercise can lower insulin responses 12-24h post-exercise; however, the insulin responses to alternate or consecutive bouts of exercise is unknown. Thus, the purpose of this study was to examine the effect of exercise pattern on post-exercise insulin and glucose responses following a glucose challenge. Ten male participants (n = 10, mean ± SD, Age 29.5 ± 7.7years; BMI 25.7 ± 3.0kg/m2) completed three exercise trials of walking for 60min at ~ 70% of VO2max. The trials consisted of: three consecutive exercise days (3CON), three alternate exercise days (3ALT), a single bout of exercise (SB), and a no exercise control (R). Twelve to fourteen hours after the last bout of exercise or R, participants completed a 75g oral glucose tolerance test (OGTT) and blood was collected at 30min intervals for the measurement of glucose, insulin, and C-peptide. Calculated incremental area under the curve (iAUC) for glucose and C-peptide was not different between the four trials. Insulin iAUC decreased 34.9% for 3CON compared to R (p < 0.01). Three consecutive days of walking at ~ 70% VO2max improved insulin response following an OGTT compared to no exercise. It is possible, that for healthy males, the effect of a single bout of exercise or exercise bouts separated by more than 24h may not be enough stimulus to lower insulin responses to a glucose challenge.