Glucoregulatory responses to intense exercise performed in the postprandial state
American Journal of Physiology. Endocrinology and Metabolism
latory responses to intense exercise performed in the postprandial state. Am J Physiol Endocrinol Metab 278: E786-E793, 2000.-A seven-to eightfold increment in hepatic glucose production (endogenous R a ) occurs in postabsorptive (PA) intense exercise (IE). A similar response is likely present in the postprandial (PP) state, when most such exercise is performed, because 1) little evidence for increased intestinal absorption of glucose during exercise exists, and 2) intravenous glucose does not
... s glucose does not prevent it. We investigated IE in 10 PA and 8 PP fit, lean, young males who had exercised for 15 min at Ͼ84% maximum O 2 uptake, starting 3 h after a 412-kcal mixed meal. The meal induced a small rise in glycemia with sustained insulin and glucagon increases. Preexercise glucose total R a and utilization (R d ) were equal and ϳ130% of the PA level. Exercise hyperglycemia in PP was delayed and diminished and, in early recovery, was of shorter duration and lesser magnitude (P ϭ 0.042). Peak catecholamine (12-to 16-fold increase) and R a (PP: 11.5 Ϯ 1.4, PA: 13.8 Ϯ 1.4 mg·kg Ϫ1 · min Ϫ1 ) responses did not differ, and their responses during exercise were significantly correlated. Exercise glucagon, insulin, and glucagon-to-insulin responses were small or not significant. R d reached the same peak (PP: 8.0 Ϯ 0.6, PA: 9.3 Ϯ 0.8 mg · kg Ϫ1 · min Ϫ1 ) but was greater at 20-120 min of recovery in PP (P ϭ 0.001). Therefore, the total R a response to IE is preserved despite the possibility of prior PP suppression of endogenous R a and is consistent with catecholamine mediation. Post-IE hyperglycemia is reduced in the postprandial state.