Overview
The goal of this experimental study is to determine how stressors that do not directly impact energy state or energy demands (hereafter called "non-energetic stressors") affect reproductive health in pre-menopausal women. It aims to do this by answering the following main questions: Do non-energetic stressors create a stress response? How does the stress response impact sex hormone concentration and thus menstrual dysfunction? If stress caused by non-energetic stressors does impact sex hormone concentration, does it do so primarily at the level of the brain or the level of the ovary? Participants will be enrolled in this study for 6 months. For two of these months, they will undergo a short stress intervention and provide samples to measure hormone concentration and total energy expenditure.
Description
The Reproductive Suppression Model posits that due to the high cost and failure rate of human reproduction, the female body maximizes lifetime reproductive fitness by suppressing reproduction during poor conditions (where likelihood of offspring survival is low) until conditions are more favorable. The hormonal mechanism for this suppression when calories are scarce and the female body is in low energy availability (LEA) has been studied. However, the mechanism for this suppression in the presence of stressors unrelated to low energy availability, but which could still negatively impact offspring survival, is much less clear. The investigators define such stressors, which do not impact energy state or energetic demands, as "non-energetic stressors." Thus, the aim of this study is to determine if non-energetic stressors drive reproductive suppression in humans. The investigators will assess this by testing the impact of a stress intervention on the stress hormones cortisol and norepinephrine, and in turn if the levels of these stress hormones predict the levels of sex hormones associated with the menstrual cycle. Finally, the investigators will assess if changes in stress hormones change total and basal energy expenditure.
Eligibility
Inclusion Criteria:
- Adult pre-menopausal females, 18-45 years old
- Habitually sedentary (less than 60 minutes MVPA/week) for Exercise cohort
Exclusion Criteria:
- Individuals on hormonal birth control (oral contraception, injection, implant, or intrauterine device)
- Individuals with incidence in the last 6 months of childbirth, lactation, pregnancy, or functional hypothalamic amenorrhea (FHA)
- Individuals with reproductive disorders (e.g. endometriosis, polycystic ovarian syndrome (PCOS))
- Individuals taking thyroid medications
- Individuals who have undergone or are undergoing menopause
- MVPA >60 min/week (for Exercise cohort)
