title: Cardiovascular response to short-term fasting in menstrual phases in young women: an observational study.
abstract: BACKGROUND
  Menstrual cycle-related symptoms are an important health issue for many women, and some may affect cardiac autonomic regulation. In the present study, we evaluated the cardiovascular and physiological stress response to 12-h short-term fasting in the menstrual phases of healthy young women.
  
  
  METHODS
  We performed a randomized crossover study. Subjects were seven female university students (age: 22.3 ± 1.0 years). The experiments comprised four sessions: meal intake in the follicular phase, meal intake in the luteal phase, fasting in the follicular phase, and fasting in the luteal phase. All subjects participated in a total of four experimental sessions during two successive phases (follicular and luteal phase in the same menstrual cycle, or luteal phase and follicular phase in the next menstrual cycle) according to a randomized crossover design. R-R intervals were continuously recorded before and after meals, and power spectral analysis of heart rate variability was performed. Other physiological data were obtained before and 20, 40, 60, and 80 min after meal intake or after the corresponding time point of meal intake (fasting in the follicular or luteal phase).
  
  
  RESULTS
  Heart rate decreased during fasting in the follicular and luteal phases. High frequency power increased during fasting in the follicular and luteal phases. In addition, salivary cortisol concentrations decreased during fasting in the luteal phase.
  
  
  CONCLUSIONS
  In the present study, short-term fasting resulted in higher parasympathetic activity and lower cortisol levels in the luteal phase in these young women. These results indicate a possibility to produce an anti-stress effect in the luteal phase, which may reduce menstrual symptoms.
authors: Graduate School of Human Development and Environment, Kobe University, Kobe, Japan. ohara@stu.kobe-u.ac.jp.|Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan. ohara@stu.kobe-u.ac.jp.
authors: Kumiko
authors: K
authors: Ohara
authors: Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Japan. dyokita@ipc.shizuoka.ac.jp.
authors: Yoshimitsu
authors: Y
authors: Okita
authors: Department of Public Health, Kinki University Faculty of Medicine, Osaka-Sayama, Japan. kouda@med.kindai.ac.jp.
authors: Katsuyasu
authors: K
authors: Kouda
authors: Department of Childhood Education, Kyoto Seibo College, Kyoto, Japan. tmase@jc.seibo.ac.jp.
authors: Tomoki
authors: T
authors: Mase
authors: Department of Early Childhood Education, Heian Jogakuin (St. Agnes') College, Kyoto, Japan. c-miyawaki@heian.ac.jp.
authors: Chiemi
authors: C
authors: Miyawaki
authors: Graduate School of Human Development and Environment, Kobe University, Kobe, Japan. hal@kobe-u.ac.jp.
authors: Harunobu
authors: H
authors: Nakamura
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D055815:Young Adult; D002320:Cardiovascular Physiological Phenomena; D002940:Circadian Rhythm / Q000502:physiology; D018592:Cross-Over Studies; D005215:Fasting; D006339:Heart Rate / Q000502:physiology; D008597:Menstrual Cycle / Q000502:physiology