Plasma Estradiol Concentrations Accompanying Acute Moderate Intensity Endurance Exercise in Obese and Lean African American and Caucasian women by Adipose Phenotype

Plasma estradiol concentrations are thought to be elevated in obese African American women with upper body adiposity. Exercise may relieve these higher than normal estradiol concentrations. However, it is unclear if acute moderate intensity exercise can produce differences in plasma estradiol concentrations in obese women. Purpose: There were two purposes for the current study: 1) to determine if a relationship exists between mean immediate-post exercise plasma estradiol concentrations and two predictor variables: ethnicity (African American and Caucasian) and adipose phenotype (lean, upper body adiposity, lower body adiposity) and 2) to determine if a relationship exists between mean resting plasma estradiol concentrations and two predictor variables: ethnicity and adipose phenotype. Methods: Seventy-two women completed the study. Basic anthropometrics and an estimated VO2max treadmill test utilizing a modified Balke protocol were measured on day I. Adipose phenotype was determined by the waist hip ratio, body mass index and body fat percentage via dual-X-ray absorptiometry scan on day I. Plasma estradiol concentrations were measured at rest and immediate-post walking on a treadmill for 30-minutes at a moderate intensity (40-60% heart rate reserve) on day 2. Results: Forward multiple linear regression indicated that ethnicity and adipose phenotype did not predict immediate-post exercise or resting follicular-phase plasma estradiol concentrations. Further, ANCOVA analysis revealed no significant difference in immediate-post exercise or resting estradiol concentrations by ethnicity or adipose phenotype while controlling for resting plasma estradiol concentrations. Conclusion: A novel finding of this research determined that immediate-post plasma estradiol concentrations were similar across the groups after moderate intensity exercise. A secondary finding of this research determined that resting plasma estradiol concentrations were similar across the groups. Future research is needed to determine if chronic moderate intensity treadmill walking can produce differences in estradiol concentrations in women based on ethnicity and adipose phenotype.