Gender differences in glucoregulatory responses to intense exercise

We compared glucoregulatory responses to intense exercise (14 min at 88% ma ximum O-2 uptake) between genders (16 men, 12 women). Analysis of covarianc e of maximum O-2 uptake showed no gender effect, with 82% of variance due t o fat-free mass (FFM). Glycemia rose comparably during exercise but was hig her in women during recovery (P = 0.02). Glucose production [rate of appear ance (R-a); in mg/min] increased markedly in both; stepwise multiple regres sion and analysis of covariance of R-a (peak and incremental area under the curve) showed no effect of gender, body weight, or FFM. Glucose uptake [ra te of disappearance (R-d)] increased less than R-a and slower in women. R-d area under the curve related to FFM (P = 0.01) but not gender or body weig ht. Norepinephrine and epinephrine responses (13-18x baseline) were the sam e and correlated significantly with R-a. Exercise insulin and glucagon chan ges were slight, but postexercise hyperinsulinemia was greater in women (P = 0.018), along with higher R-d Therefore, intense exercise glucoregulation is qualitatively similar between genders, with a "feed-forward" regulation of R-a (consistent with catecholamine mediation). However, women have a le sser R-d response, related to FFM. This combination leads to greater recove ry-period hyperglycemia and hyperinsulinemia.