Affiliation:
1. Department of Physical Therapy Education, Elon College, Elon College, North Carolina 27244; and
2. Department of Exercise Science and Sport Studies, Rutgers University, New Brunswick, New Jersey 08903
Abstract
The effects of menstrual cycle phase and carbohydrate (CHO) supplementation were investigated during prolonged exercise. Nine healthy, moderately trained women cycled at 70% peak O2 consumption until exhaustion. Two trials were completed during the follicular (Fol) and luteal (Lut) phases of the menstrual cycle. Subjects consumed 0.6 g CHO ⋅ kg body wt− 1 ⋅ h− 1(5 ml/kg of a 6% CHO solution every 30 min beginning at min 30 of exercise) or a placebo drink (Pl) during exercise. Time to exhaustion during CHO increased from Pl values ( P < 0.05) by 14.4 ± 8.5 (Fol) and 11.4 ± 7.1% (Lut); no differences were observed between menstrual cycle phases. CHO attenuated ( P < 0.05) the decrease in plasma glucose and insulin and the increase in plasma free fatty acids, tryptophan, epinephrine, and cortisol observed during Pl for both phases. Plasma alanine, glutamine, proline, and isoleucine were lower ( P < 0.05) in Lut than in Fol phase. CHO resulted in lower ( P < 0.05) plasma tyrosine, valine, leucine, isoleucine, and phenylalanine. These results indicate that the menstrual cycle phase does not alter the effects of CHO supplementation on performance and plasma levels of related substrates during prolonged exercise.
Publisher
American Physiological Society
Subject
Physiology (medical),Physiology
Cited by
73 articles.
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