Figure 2.

Subjects with impaired glucose tolerance or type 2 diabetes (N = 105) underwent 12 to 16 weeks of moderate-intensity exercise training, 5 days per week, 60 minutes per day. Exercise responsiveness of first-phase oral GSIS (A) and DI (B), and second-phase GSIS (C) and DI (D) were measured as the postminus preexercise (Δ) values. Individual subject data points are plotted on the x-axis. Y-axis data above the origin indicate an exercise training-induced increase in that variable; data below the origin represent a training-induced decrease. First-phase GSIS is reported as the area under the serum C-peptide response curve during the first 30 minutes following the ingestion of 75 g glucose. Second-phase GSIS is reported as the area under the C-peptide curve from 30 to 120 minutes after glucose ingestion. DI is calculated as the product of GSIS and insulin sensitivity.