Effect of Intense Training on Ovarian Function and Bone Turnover
Condition: Amenorrhea
MeSH terms: Amenorrhea
Study type: Interventional

Summary: 
      The investigators propose a prospective, longitudinal, department funded study protocol to
      evaluate whether changes in energy availability, during a period of highly intensified
      exercise training, will increase bone turnover markers and decrease ovarian function and
      exercise performance, in a dose-dependent fashion in competitive female athletes.
    

Detailed description: 
      Female athletes participating in sports which emphasize leanness as a factor to success,
      while also imposing large exercise training loads, present a high prevalence of endocrine and
      metabolic alterations linked to low energy stores, including suppressed ovarian function and
      bone loss. Increased bone turnover resulting from low energy stores and suppressed estrogen
      production may hold the most adverse consequences for long term health, increasing the risk
      of premature osteopenia, while increasing the risk of stress fractures in the short term.
      Chronically low energy stores may also contribute to the development of overreaching and
      overtraining syndromes, characterized by excessive, lasting fatigue and long-term decreases
      in performance, which can compromise these athletes' health and athletic career. The
      investigators propose the first longitudinal study aiming to demonstrate the link between low
      energy status, impaired ovarian function, bone turnover and decreased performance in
      free-living, competitive female athletes. After a 4-week baseline period of habitual
      training, athletes will undergo 4 weeks of intensified training (IT), during which the
      exercise load is increased by 30% from their individual baseline load in order to sharply
      increase energy expenditure. As athletes will be let to freely adjust their food intake, the
      investigators aim to test the hypothesis that athletes will fail to adjust food intake
      sufficiently to match energy expenditure, and that the resulting decrease in energy
      availability (EA, energy intake - energy expenditure from exercise) will influence, in a
      dose-dependent fashion, the suppression of estrogen production, the increase in bone turnover
      and the severity of performance decrement. The IT period will then be followed by a 2-week
      taper (REC), in which exercise training volume will be reduced by 50% from baseline. The
      investigators will assess whether EA returns to baseline values, and characterize changes in
      bone turnover during this recovery period. It is hypothesized that any improvements in
      exercise performance resulting from IT + REC will occur in athletes who were able to remain
      closest to a balanced energy state during IT. Concretely linking EA to both performance and
      bone health may incentivize female athletes to adopt more adequate feeding behaviors for
      their activity level.
    

Intervention name(s): Intensified Training
Intervention type(s): Behavioral
Intervention description(s): Volunteers will increase exercise training by 30% from baseline
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: exercise training