title: Heat acclimation and physical training adaptations of young women using different contraceptive hormones.
abstract: Although endogenous and exogenous steroid hormones affect numerous physiological processes, the interactions of reproductive hormones, chronic exercise training, and heat acclimation are unknown. This investigation evaluated the responses and adaptations of 36 inactive females [age 21 +/- 3 (SD) yr] as they undertook a 7- to 8-wk program [heat acclimation and physical training (HAPT)] of indoor heat acclimation (90 min/day, 3 days/wk) and outdoor physical training (3 days/wk) while using either an oral estradiol-progestin contraceptive (ORAL, n = 15), a contraceptive injection of depot medroxyprogesterone acetate (DEPO, n = 7), or no contraceptive (EU-OV, n = 14; control). Standardized physical fitness and exercise-heat tolerance tests (36.5 degrees C, 37% relative humidity), administered before and after HAPT, demonstrated that the three subject groups successfully (P < 0.05) acclimated to heat (i.e., rectal temperature, heart rate) and improved muscular endurance (i.e., sit-ups, push-ups, 4.6-km run time) and body composition characteristics. The stress of HAPT did not disrupt the menstrual cycle length/phase characteristics, ovulation, or plasma hormone concentrations of EU-OV. No between-group differences (P > 0.05) existed for rectal and skin temperatures or metabolic, cardiorespiratory, muscular endurance, or body composition variables. A significant difference post-HAPT in the onset temperature of local sweating, ORAL (37.2 +/- 0.4 degrees C) vs. DEPO (37.7 +/- 0.2 degrees C), suggested that steroid hormones influenced this adaptation. In summary, virtually all adaptations of ORAL and DEPO were similar to EU-OV, suggesting that exogenous reproductive hormones neither enhanced nor impaired the ability of women to complete 7-8 wk of strenuous physical training and heat acclimation.
authors.affiliation: Human Performance Laboratory, Department of Kinesiology, University of Conneticut, Unit 1110, 2095 Hillside Road, Storrs, CT 06269-1110, USA.
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Armstrong
authors.forename: Carl M
authors.initials: CM
authors.lastname: Maresh
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Keith
authors.forename: Tabatha A
authors.initials: TA
authors.lastname: Elliott
authors.forename: Jaci L
authors.initials: JL
authors.lastname: Vanheest
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Scheett
authors.forename: James
authors.initials: J
authors.lastname: Stoppani
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Judelson
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: De Souza
mesh_terms: D000064:Acclimatization / Q000187:drug effects / Q000502:physiology; D000222:Adaptation, Physiological / Q000187:drug effects* / Q000502:physiology*; D000328:Adult; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage*; D017079:Exercise Tolerance / Q000187:drug effects / Q000502:physiology*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000008:administration & dosage*; D006358:Hot Temperature; D006801:Humans; D010806:Physical Education and Training / Q000379:methods; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*
chemical_list: D003280:Contraceptives, Oral, Synthetic; D012739:Gonadal Steroid Hormones