Bioenergetics of Exercise-Induced Menstrual Disturbances
Condition: Menstruation Disturbances; Luteal Phase Defect; Amenorrhea; Oligomenorrhea
MeSH terms: Amenorrhea; Menstruation Disturbances; Oligomenorrhea
Study type: Interventional

Summary: 
      Menstrual disturbances are frequently observed in physically active women and female
      athletes. Short term prospective studies have shown that diet and exercise interventions can
      lead to decreases in Luteinizing hormone (LH) pulsatility, however these studies are unable
      to capture further changes in menstrual status. One longer term prospective study over two
      menstrual cycles showed that weight loss elicited menstrual disturbances, but there were no
      quantifiable measurements of energy availability. Thus, the primary purpose of this study was
      to assess how varying levels of energy deficiency created through a combination of caloric
      restriction and exercise affect menstrual function in young, premenopausal, sedentary women.
    

Detailed description: 
      Long term energy deficiency in women can lead to functional hypothalamic amenorrhea (FHA),
      which can cause many health detriments such as osteopenia, stress fractures, transient
      infertility, dyslipidemia, and impaired endothelial function. Though studies involving diet
      and exercise interventions have shown how energy deficiency can lead to menstrual
      disturbances prospectively, this study aims to extend those findings by measuring the
      magnitude of energy deficit that could lead to these disturbances. Hypotheses for this study
      are: 1) there would be a dose-response relation between the induction of menstrual
      disturbances (luteal phase defects, anovulation, and oligomenorrhea) and the magnitude of
      energy deficiency such that the intervention groups experiencing a greater energy deficit
      would incur a significantly greater incidence of menstrual cycle disturbances and 2) the
      intervention groups experiencing a greater energy deficit would incur a greater incidence of
      more severe menstrual cycle disturbances.

      The study included one baseline menstrual cycle and 3 intervention menstrual cycles. During
      the baseline period, participants were randomly assigned to an experimental group for
      intervention menstrual cycles 1, 2, and 3 of the study. The goal of the subject groupings was
      to test the impact of varying levels of an energy deficit created by the combination of
      caloric restriction and exercise on menstrual function. They were assigned to either a
      control group that did not exercise and consumed a number of calories estimated to maintain
      body weight, a control group that exercised but received extra food calories to remain in
      energy balance (EXCON), or one of four groups that exercised and were prescribed reduced
      energy intake to create varying levels of an energy deficit. Specifically, the four groups of
      energy deficit were 1) an increase of 15 percent kcal of exercise (15 percent deficit, ED1),
      2) an increase of 30 percent kcal of exercise (30 percent deficit, ED2), 3) a decrease of 15
      percent in dietary intake combined with an increase of 15 percent of exercise, (30 percent
      deficit 15/15, ED2), and 4) a decrease of 30 percent in dietary intake combined with an
      increase of 30 percent kcal of exercise (60 percent deficit, ED3). The number of participants
      for analysis was 34 participants in the following groups: EXCON (n = 8), ED1 (n = 6), ED2 (n
      = 12), and ED3 (n = 8).

      Baseline energy needs were assessed during the baseline cycle. Resting metabolic rate and
      nonexercise physical activity were added to determine a caloric need for the day. Caloric
      intake was supervised throughout the entire study, and meals were comprised of 55 percent
      carbohydrates, 30 percent fat, and 15 percent protein. Exercise training was also supervised,
      and maximal oxygen consumption (VO2 max) was calculated. Menstrual status was assessed
      through analysis of daily urinary metabolites of estrone-1-glucuronide (E1G), pregnanediol
      glucuronide (PdG), and midcycle LH. Underwater weighing and a digital scale were used to
      assess body composition, and fasting blood samples were collected to assess metabolic
      hormones.
    

Intervention name(s): Sedentary Control; Exercising control; 15 percent energy deficit; 30 percent energy deficit; 30 percent energy deficit (15/15); 60 percent energy deficit
Intervention type(s): Other; Other; Other; Other; Other; Other
Intervention description(s): Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had calories sufficient to maintain body weight. Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.; Exercise: Participants engaged in supervised exercise training in Noll Laboratory Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had calories sufficient to maintain body weight and additional calories to remain in energy balance. Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.; Exercise: Participants engaged in supervised exercise training in Noll Laboratory that was equal to 15 percent of the participants' daily caloric needs.
Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had calories to meet metabolic needs (before 15 percent deficit exercise). Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.; Exercise: Participants engaged in supervised exercise training in Noll Laboratory that was equal to 30 percent of the participants' daily caloric needs.
Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had calories to meet metabolic needs (before 30 percent deficit exercise). Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.; Exercise: Participants engaged in supervised exercise training in Noll Laboratory that was equal to 15 percent of the participants' daily caloric needs.
Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had 15 percent less calories than those needed to meet metabolic needs. Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.; Exercise: Participants engaged in supervised exercise training in Noll Laboratory that was equal to 30 percent of the participants' daily caloric needs.
Diet: Participants consumed meals in the General Clinical Research Center metabolic kitchen that had 30 percent less calories than those needed to meet metabolic needs. Diet composition was 55 percent carbohydrates, 30 percent fat, and 15 percent protein.
Other intervention name(s): Diet; Diet; Diet and exercise; Diet and exercise; Diet and exercise; Diet and exercise
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Energy Balance; Menstrual Cycle Disturbance; Luteal Phase Defect; Amenorrhea; Oligomenorrhea