Unaltered insulin sensitivity after resistance exercise bout by postmenopausal women

CHAPMAN, J., A. W. GARVIN, A. WARD, and G. D. CARTEE. Unaltered insulin sensitivity after resistance exercise bout by postmenopausal women. Med. Sci. Sports Exerc., Vol. 34, No. 6, pp. 936-941, 2002. Purpose: The major aims of this study were to determine whether a single session of resistance exercise would alter insulin sensitivity. glucose effectiveness, and C-peptide response to glucose challenge in a group of previously sedentary, postmenopausal women. Methods: Ten postmenopausal women (aged 57.5 +/- 1.6 yr) were studied. Each participant underwent two frequently sampled intravenous glucose tolerance tests (FSIVGTT): without prior exercise (no exercise), and postexercise (15 h after a session of resistance exercise: three sets of 10 repetitions performed at 50%, 75%, and 100% of 10-repetition maximum for 7 exercises). Insulin sensitivity and glucose effectiveness were determined according to Bergman's minimal model procedure. In addition, C-peptide concentration and glucose disappearance were measured. Results: There was no significant difference between trials for insulin sensitivity, glucose effectiveness, glucose disappearance, or area under the curve (AUC) for glucose or insulin during the glucose challenge. AUC for C-peptide tended (P = 0.059) to be 10% higher in the postexercise versus no exercise trial, and C-peptide values were significantly (P less than or equal to 0.02) higher at several time points (60, 70 140, and 180 min) during the postexercise compared with no exercise trial. Conclusions: In contrast to previously reported results with young men and women after a single bout of endurance exercise, insulin sensitivity was unaltered by a single session of resistance exercise in postmenopausal women. Higher plasma C-peptide values concomitant with unchanged insulin values provide evidence that resistance exercise may have induced a slightly higher insulin secretion and a proportional increase in insulin clearance.