BIOENERGETICS OF EXERCISE-INDUCED MENSTRUAL DISTURBANCES

Project: Research project

Project Details

Description

DESCRIPTION: (Scanned from the applicant's abstract) The suppression of
menstrual cyclicity due to strenuous exercise can cause infertility, severe
bone demineralization, increase fracture risk, and possibly increase the risk
of cardiovascular disease. Recent findings in humans and animals have strongly
suggested that exercise-induced menstrual disturbances are primarily caused by
low energy availability and not by other factors, such as the physical stress
of exercise per se. While some studies have quantified energy balance
associated with short-term decreases in plasma levels of reproductive hormones,
the bioenergetics associated with the induction and reversal of clinically
recognized menstrual disturbances in exercising women remain unclear.

The first specific aim of this proposal is to test the hypothesis that there is
a direct relationship between the severity of exercise-induced menstrual
disturbances and the magnitude of negative energy balance. In addition to
weight loss, crosssectional studies in humans suggest that exercise-induced
menstrual disturbances are associated with adaptive mechanisms to conserve
energy, i.e., alterations in circulating metabolic hormones and substrates, and
reductions in components of 24 h energy expenditure such as metabolic rate.
Since in vivo and in vitro studies using animal models have suggested
mechanistic roles for key metabolic hormones and substrates in the modulation
of GnRH neuronal activity with changes in energy balance, prospective studies
in humans are now necessary to identify the time course and magnitudes of
change of potential key metabolic signals during the development of EIMD. The
second specific aim of this proposal is to test the hypothesis that
exercise-induced menstrual disturbances are triggered by the development of a
particular metabolic state defined by adaptive mechanisms to conserve energy.
The significance of this research relates to conditions of infertility, delayed
puberty, anovulation, anorexia nervosa, exercise-induced amenorrhea, and the
recently identified high incidence of luteal phase disturbances and anovulatory
cycles in women exercising even at recreational levels. We expect the results
of these studies to provide new and useful information for making specific
recommendations regarding the exercise and dietary practices concomitant with
maintaining normal, ovulatory menstrual cycles and adequate levels of
circulating estrogen and progesterone. The results will also expand our
understanding of the mechanism of the modulation of reproductive function by
energy availability.
StatusFinished
Effective start/end date5/10/014/30/02

Funding

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $450,166.00

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