title: Effect of menstrual cycle phase on exercise performance of high-altitude native women at 3600 m.
abstract: At sea level normally menstruating women show increased ventilation (VE) and hemodynamic changes due to increased progesterone (P) and estrogen (E2) levels during the mid-luteal (L) compared to the mid-follicular (F) phase of the ovarian cycle. Such changes may affect maximal exercise performance. This repeated-measures, randomized study, conducted at 3600 m, tests the hypothesis that a P-mediated increase in VE increases maximal oxygen consumption (V(O(2)max)) during the L phase relative to the F phase in Bolivian women, either born and raised at high altitude (HA), or resident at HA since early childhood. Subjects (N=30) enrolled in the study were aged 27.7 +/- 0.7 years (mean +/- S.E.M.) and non-pregnant, non-lactating, relatively sedentary residents of La Paz, Bolivia, who were not using hormonal contraceptives. Mean salivary P levels at the time of the exercise tests were 63.3 pg ml(-1) and 22.9 pg ml(-1) for the L and F phases, respectively. Subset analyses of submaximal (N=23) and maximal (N=13) exercise responses were conducted only with women showing increased P levels from F to L and, in the latter case, with those also achieving true (V(O(2)max)). Submaximal exercise VE and ventilatory equivalents were higher in the L phase (P<0.001). P levels were significantly correlated to the submaximal exercise VE (r=0.487, P=0.006). Maximal work output (W) was higher (approximately 5 %) during the L phase (P=0.044), but (V(O(2)max)) (l min(-1)) was unchanged (P=0.063). Post-hoc analyses revealed no significant relationship between changes in P levels and changes in (V(O(2)max))) from F to L (P=0.072). In sum, the menstrual cycle phase has relatively modest effects on ventilation, but no effect on (V(O(2)max)) of HA native women.
authors.affiliation: Department of Anthropology, The University at Albany, State University of New York, 12222, USA. tbrutsae@csc.albany.edu
authors.forename: Tom D
authors.initials: TD
authors.lastname: Brutsaert
authors.forename: Hilde
authors.initials: H
authors.lastname: Spielvogel
authors.forename: Esperanza
authors.initials: E
authors.lastname: Caceres
authors.forename: Mauricio
authors.initials: M
authors.lastname: Araoz
authors.forename: Robert T
authors.initials: RT
authors.lastname: Chatterton
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Vitzthum
mesh_terms: D000328:Adult; D000531:Altitude; D001838:Bolivia; D015444:Exercise / Q000502:physiology*; D005260:Female; D005498:Follicular Phase; D006801:Humans; D008183:Luteal Phase; D008597:Menstrual Cycle; D010101:Oxygen Consumption; D011374:Progesterone / Q000032:analysis; D012123:Pulmonary Ventilation; D012463:Saliva / Q000737:chemistry
chemical_list: D011374:Progesterone