A single exercise session increases insulin sensitivity in normal weight and overweight/obese adolescents

Abstract

We measured the effect of an aerobic exercise session on postprandial glucose control in adolescents with habitually low-physical activity. The goal was to determine if the acute or residual response of exercise was altered in people who are overweight/obese (OW/Ob). Eleven normal weight, body mass index (NW, BMI = 48 ± 13 percentile) and 12 OW/Ob (BMI = 91 ± 5 percentile) participants completed 3 trials. In the no exercise (No Ex) trial, participants rested quietly before and after consuming a test meal. In the other 2 trials, a 45-minute aerobic exercise session was performed either 17-hour (Prior Day Ex) or 40 minutes (Same Day Ex) before the test meal. On all trials, the OW/Ob group had higher fasting glucose (~6%) and insulin (~66%), and lower insulin sensitivity (~9%) than the NW group. The Same Day Ex and Prior Day Ex trials resulted in reduced area under the curve for glucose (6% on both trials, P < .01) and insulin (15% and 13%, respectively, P < .03), and increased insulin sensitivity (8% and 6%, respectively, P < .01). The magnitudes of those effects did not differ between the NW and OW/Ob groups. Plasma fatty acids declined and carbohydrate oxidation increased after the meal, but did not differ among trials or groups. The results demonstrate that moderate intensity aerobic exercise increases insulin sensitivity in NW and OW/Ob adolescents and that the beneficial effects of exercise last up to 17 hours. The acute impact of exercise on metabolic health in adolescents is not impaired in overweight/obese participants.

Keywords: glucose tolerance; mixed meal; physical activity.

Figure 1

Plasma glucose responses. Glucose excursion curves for NW group (A) and OW/Ob group (B). Pre-meal baseline = 0 minutes. (C) Total glucose area under the curve (AUC) for each trial. (D) Individual values for the difference in glucose AUC (delta AUC) between each exercise trial and the No Ex trial, respectively. Values for panels A–C shown as mean ± SEM. Legend applies to all panels. *Prior Day Ex versus No Ex within group, p < 0.05. † Same Day Ex versus No Ex within group, p < 0.05.

Figure 2

Serum insulin responses. Insulin excursion curves for NW group (A) and OW/Ob group (B). Pre-meal baseline = 0 minutes. (C) Total insulin area under the curve (AUC) for each trial. (D) Individual values for the difference in insulin AUC (delta AUC) between each exercise trial and the No Ex trial, respectively. Values for panels A–C shown as mean ± SEM. Legend applies to all panels. *Prior Day Ex versus No Ex within group, p < 0.05. † Same Day Ex versus No Ex within group, p < 0.05.

Figure 3

Serum C-peptide responses. C-peptide excursion curves for NW group (A) and OW/Ob group (B). Pre-meal baseline = 0 minutes. (C) Total C-peptide area under the curve (AUC) for each trial. (D) Individual values for the difference in C-peptide AUC (delta AUC) between each exercise trial and the No Ex trial, respectively. Values for panels A–C shown as mean ± SEM. The legend applies to all panels. *Prior Day Ex versus No Ex within group, p < 0.05. † Same Day Ex versus No Ex within group, p < 0.05.

Figure 4

Insulin sensitivity. (A) Insulin sensitivity values (mean ± SEM) for each trial. (B) Individual values for the difference (delta) in insulin sensitivity between the exercise trials and the No Ex trial, respectively. The legend applies to both panels. *Greater than No Ex trial within group, p < 0.05. Insulin sensitivity was ~9% lower (p < 0.05) in the OW/Ob group versus the NW group during each trial.