OBJECTIVE To investigate the effectiveness of exercise on the regulation of insulin sensitivity. METHODS Eleven premenopausal women, with body fat mass from the normal range to moderate obesity, were examined with glucose clamp at 10 mmol/L glucose concentration to determine insulin-dependent and non-insulin-dependent (after somatostatin inhibition of endogenous insulin production) glucose uptake (= IDGU and NIDGU respectively) before and 24 hrs after a glycogen-decreasing exercise. RESULTS IDGU, but not NIDGU, increased after exercise. The degree of increase of IDGU after exercise showed negative correlations with body mass index (borderline, significance), the waist to hip circumference ratio, fasting free testosterone and free fatty acid concentrations, as well as diastolic blood pressure (borderline significance), and a positive relationship to sex hormone binding globulin concentration and IDGU before exercise. CONCLUSIONS It is concluded that only IDGU contributes to the augmentation of insulin sensitivity after a glycogen-decreasing exercise in women. Additionally, the increase of IDGU is less in abdominal obesity, and negatively dependent on free fatty acid concentrations, hyperandrogenism and hyperinsulinaemia, all putative pathogenetic factors for insulin resistance.