Luteal Phase Deficiency in Recreational Runners: Evidence for a Hypometabolic State
Bibliographic record
Abstract
Exercising women with amenorrhea exhibit a hypometabolic state. The purpose of this study was to evaluate the relationship of luteal phase deficient (LPD) menstrual cycles to metabolic hormones, including thyroid, insulin, human GH (hGH), leptin, and IGF-I and its binding protein levels in recreational runners. Menstrual cycle status was determined for three consecutive cycles in sedentary and moderately active women. Menstrual status was defined as ovulatory or LPD. Subjects were either sedentary (n = 10) or moderately active (n = 20) and were matched for age (27.7 +/- 1.2 yr), body mass (60.2 +/- 3.3 kg), menstrual cycle length (28.4 +/- 0.9 d), and reproductive age (14.4 +/- 1.2 yr). Daily urine samples for the determination of estrone conjugates, pregnanediol 3-glucuronide, and urinary levels of LH were collected. Blood was collected on a single day during the follicular phase (d 2-6) of each menstrual cycle for analysis of TSH, insulin, total T3, total T4, free T4, leptin, hGH, IGF-I, and IGF binding protein (IGFBP)-1 and IGFBP-3. Among the 10 sedentary subjects, 28 of 31 menstrual cycles were categorized as ovulatory (SedOvul). Among the 20 exercising subjects, 24 menstrual cycles were included in the ovulatory category (ExOvul), and 21 menstrual cycles were included in the LPD category (ExLPD). TSH, total T4, and free T4 levels were not significantly different among the three categories of cycles. Total T3 was suppressed (P = 0.035) in the ExLPD (1.63 +/- 0.07 nmol/liter) and the ExOvul categories of cycles (1.75 +/- 0.8 nmol/liter) compared with the SedOvul category of cycles (2.15 +/- 0.1 nmol/liter). Leptin levels were lower (P < 0.001) in both the ExOvul (5.2 +/- 0.4 microg/liter) and the ExLPD categories of cycles (5.1 +/- 0.4 microg/liter) when compared with the SedOvul category of cycles (13.7 +/- 1.7 microg/liter). Insulin was lower (P = 0.009) only in the ExLPD category of cycles (31.9 +/- 2.8 pmol/liter) compared with the SedOvul (60.4 +/- 8.3 pmol/liter) and ExOvul (61.8 +/- 10.4 pmol/liter) categories of cycles. IGF-I, IGFBP-1, IGFBP-3, IGF-I/IGFBP-1, IGF-I/IGFBP-3, and hGH were comparable among the different categories of cycles. These data suggest that exercising women with LPD menstrual cycles exhibit hormonal alterations consistent with a hypometabolic state that is similar to that observed in amenorrheic athletes and other energy-deprived states, although not as comprehensive. These alterations may represent a metabolic adaptation to an intermittent short-term negative energy balance.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".