title: Exercise performance over the menstrual cycle in temperate and hot, humid conditions.
abstract: OBJECTIVE
  This study investigated the effects of the menstrual cycle on prolonged exercise performance both in temperate (20°C, 45% relative humidity) and hot, humid (32°C, 60% relative humidity) conditions.
  
  
  METHODS
  For each environmental condition, 12 recreationally active females were tested during the early follicular (day 3-6) and midluteal (day 19-25) phases, verified by measurement of estradiol and progesterone. For all four tests, thermoregulatory, cardiorespiratory, and perceptual responses were measured during 60 min of exercise at 60% of maximal oxygen consumption followed by an incremental test to exhaustion.
  
  
  RESULTS
  No differences in exercise performance between menstrual cycle phases were found during temperate conditions (n = 8) despite a higher resting and submaximal exercise core temperature (Tc) in the luteal phase. In hot, humid conditions (n = 8), however, prolonged exercise performance, as exercise time to fatigue, was significantly reduced during the luteal phase. This finding was not only accompanied by higher resting and submaximal exercise Tc but also a higher rate of increase in Tc during the luteal phase. Furthermore, submaximal exercise HR, minute ventilation, and RPE measures were higher during the luteal phase in hot, humid conditions. No significant differences were found over the menstrual cycle in heat loss responses (partitional calorimetry, sweat rate, upper arm sweat composition) and Tc at exhaustion.
  
  
  CONCLUSIONS
  In temperate conditions, no changes in prolonged exercise performance were found over the menstrual cycle, whereas in hot, humid conditions, performance was decreased during the luteal phase. The combination of both exercise and heat stress with the elevated luteal phase Tc at the onset of exercise resulted in physiological and perceptual changes and a greater thermosensitivity, which may explain the decrease in performance.
authors: School of Environmental and Life Sciences, University of Newcastle, Newcastle, Australia. jb.fabre@esp-consulting.fr
authors: Xanne A K
authors: XA
authors: Janse DE Jonge
authors: Martin W
authors: MW
authors: Thompson
authors: Vivienne H
authors: VH
authors: Chuter
authors: Leslie N
authors: LN
authors: Silk
authors: Jeanette M
authors: JM
authors: Thom
mesh_terms: D000328:Adult; D001833:Body Temperature Regulation; D004967:Estrogens / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005260:Female; D005498:Follicular Phase / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008183:Luteal Phase / Q000502:physiology; D008597:Menstrual Cycle / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D011374:Progesterone / Q000097:blood; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D004967:Estrogens; D011374:Progesterone