title: Menstrual cycle effects on perceived exertion and pain during exercise among sedentary women.
abstract: BACKGROUND
  Increasing cardiovascular fitness through exercise participation among sedentary people is important for decreasing all-cause mortality. From an intervention perspective, identifying modifiable factors that maximize the successful initiation of exercise is of utmost importance. For women, cyclic hormonal variations can influence aspects of health and health behaviors, from smoking cessation efficacy to physiological responses to exercise. The purpose of this study was to examine the influence of menstrual cycle phase and hormonal contraceptive (HC) use on subjective response to an initial bout of moderate intensity exercise among previously sedentary women (n = 117).
  
  
  METHODS
  Women completed a treadmill exercise challenge session at 65% of their previously determined maximum oxygen consumption (Vo(2) max) during the early follicular, late follicular, or luteal phase. Participants reported ratings of perceived exertion and pain using Borg's Rating of Perceived Exertion (RPE) and CR10 scales at 10, 20, and 30 minutes during the exercise session.
  
  
  RESULTS
  There was a significant menstrual phase x birth control interaction on change in RPE [F(2, 111) = 3.75, p < 0.05] and change in perceived pain [F(2, 110) = 3.31, p < 0.05]. Women in the early follicular phase who were not using HCs had significantly greater increases in RPE and increases in pain compared with women in the late follicular and luteal phases.
  
  
  CONCLUSIONS
  Our results indicate that the use of HC and cycle phase influence sedentary women's subjective response to exercise. These results have important implications for the timing of exercise interventions aimed at increasing exercise among sedentary women.
authors.affiliation: Department of Psychology, University of New Mexico, Albuquerque, NM 87131, USA. anncwell@unm.edu
authors.forename: Ann E Caldwell
authors.initials: AE
authors.lastname: Hooper
authors.forename: Angela D
authors.initials: AD
authors.lastname: Bryan
authors.forename: Melissa
authors.initials: M
authors.lastname: Eaton
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D003276:Contraceptives, Oral / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000502:physiology*; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000503:physiopathology*; D010147:Pain Measurement; D005082:Physical Exertion / Q000502:physiology*; D057185:Sedentary Behavior; D016387:Women's Health; D055815:Young Adult
chemical_list: D003276:Contraceptives, Oral