Effect of Intense Training on Ovarian Function and Bone Turnover
| Status: | Completed |
|---|---|
| Conditions: | Women's Studies |
| Therapuetic Areas: | Reproductive |
| Healthy: | No |
| Age Range: | 18 - 40 |
| Updated: | 4/21/2016 |
| Start Date: | January 2014 |
| End Date: | December 2015 |
Impact of Intense Exercise Training on Energy Availability, Ovarian Function and Bone Turnover in Female Athletes
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.
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.
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.
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.
Inclusion Criteria:
- competitive endurance runners (racing in events ranging from 10km to ultra-marathons)
- training at least 5 days per week over the past 12 months, and more than 30 miles per
week
- regular menstrual cycles (24-35 days) over the past 6 months
- maximal oxygen consumption (VO2max) > 50ml/kg/min
- English speaking
Exclusion Criteria:
- smoker
- amenorrhea
- pregnant or lactating in the past 2 years
- chronic disease that will affect bone health, metabolism or the cardiorespiratory
system
- take medications that have cardiovascular or metabolic effects
- present any contra-indication to exercise testing (cardiovascular abnormalities)
- report any major illness or injury preventing training for more than 4 weeks over the
past 3 months
- a history of clinical anorexia nervosa or bulimia nervosa
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