POSTEXERCISE PROTEIN-CARBOHYDRATE AND CARBOHYDRATE SUPPLEMENTS INCREASE MUSCLE GLYCOGEN IN MEN AND WOMEN

We have previously demonstrated that women did not increase intramuscu lar glycogen in response to an increased percent of dietary carbohydra te (CHO) (from 60 to 75% of energy intake) (M. A. Tarnopolsky, S. A. A tkinson, S. M. Phillips, and J. D. MacDougall. J. Appl. Physiol. 78: 1 360-1368, 1995). CHO and CHO-protein (Pro) supplementation postexercis e can potentiate glycogen resynthesis compared with placebo (K. M. Zaw adzki, B. B. Yaspelkis, and J. L. Ivy. J. Appl. Physiol. 72: 1854-1859 , 1992). We studied the effect of isoenergetic CHO and CHO-Pro-Fat sup plements on muscle glycogen resynthesis in the first 4 h after enduran ce exercise (90 min at 65% peak O-2 consumption) in trained endurance athletes (men, n = 8; women, tested in midfollicular phase, n = 8). Ea ch subject completed three sequential trials separated by 3 wk; a supp lement was provided immediately and 1-h postexercise: 1) CHO (0.75 g/k g) + Pro (0.1 g/kg) + Fat (0.02 g/kg), 2) CHO (1 g/kg), and 3) placebo (Pl; artificial sweetener). Subjects were given prepackaged, isoenerg etic, isonitrogenous diets, individualized to their habitual diet, for the day before and during the exercise trial. During exercise, women oxidized more lipid than did men (P < 0.05). Both of the supplement tr ials resulted in greater postexercise glucose and insulin compared wit h Pl (P < 0.01), with no gender differences. Similarly, both of these trials resulted in increased glycogen resynthesis (37.2 vs. 24.6 mmol. kg dry muscle(-1).h(-1), CHO vs. CHO-Pro-Fat, respectively) compared w ith Pl (7.5 mmol.kg dry muscle(-1).h(-1); P < 0.001) with no gender di fferences. We conclude that postexercise CHO and CHO-Pro-Fat nutrition al supplements can increase glycogen resynthesis to a greater extent t han Pl for both men and women.