Differences in endocrine function with varying fitness capacity in postpubertal females across the weight spectrum

Arch Pediatr Adolesc Med. 2004 Apr;158(4):333-40. doi: 10.1001/archpedi.158.4.333.

Abstract

Objective: To relate endocrine and nutritional correlates of fitness in postpubertal physically active females across the normal weight spectrum to identify markers and how these might serve as associations of exercise-related endocrine disruption.

Design: Cross-sectional study analyzed by repeated-measures analysis of variance for frequent blood sampling.

Setting: A general clinical research center.

Subjects: Twenty-two healthy postpubertal female subjects recruited 2 years or more after menarche.

Main outcome measures: Maximum oxygen consumption was determined as an index of fitness and daily caloric intake was calculated from a 3-day food diary. During the follicular phase of the cycle, luteinizing hormone was sampled every 10 minutes during a 24-hour period, while follicle-stimulating hormone and cortisol were sampled hourly.

Results: For every 1-unit increase in maximum oxygen consumption, cortisol concentration increased by 2% (P =.005; 95% confidence interval, 1%-3%). However, there was no association between mean gonadotropin concentrations and fitness. Hormone concentrations were not significantly associated with body mass index or percentage of body fat. Higher mean caloric intake from a 3-day summary was inversely related to mean luteinizing hormone concentration, which decreased by 5.5% for every 100-kcal increase (P =.03; 95% confidence interval, 1%-10%). With every 1-year increase in age at menarche, follicle-stimulating hormone concentration decreased by 12% (P =.01; 95% confidence interval, 4%-19%) and cortisol concentration increased by 7% (P =.03; 95% confidence interval, 1%-12%).

Conclusions: In active adolescents, increased cortisol concentration may represent an adaptive change to exercise that may precede gonadotropin changes seen with higher levels of fitness.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Biomarkers / blood
  • Body Mass Index
  • Cross-Sectional Studies
  • Diet Records
  • Energy Intake / physiology
  • Female
  • Follicle Stimulating Hormone / blood*
  • Follicle Stimulating Hormone / physiology
  • Follicular Phase / blood
  • Follicular Phase / physiology
  • Humans
  • Hydrocortisone / blood*
  • Luteinizing Hormone / blood*
  • Luteinizing Hormone / physiology
  • Menarche / blood
  • Menarche / physiology
  • Oxygen Consumption / physiology
  • Physical Fitness / physiology*
  • Time Factors

Substances

  • Biomarkers
  • Luteinizing Hormone
  • Follicle Stimulating Hormone
  • Hydrocortisone