Estrogen Effects on Skeletal-Cardiac Biomarkers of Muscle Damage After Prolonged Aerobic Exercise in Eumenorrheic Women (2014)

Undergraduates: Timmons Williams, Michelle Pebole, Elizabeth A. Walz, Amy R. Lane

Faculty Advisor: Anthony C. Hackney
Department: Exercise & Sport Science

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Purpose: This study assessed the influence of estrogen (E2) on skeletal muscle creatine kinase (CK) and cardiac muscle CK (CK-MB) responses to prolonged aerobic exercise. Elevations in these biomarkers are indicative of muscle trauma-damage. Methods: Eumenorrheic women (n=10) who were physically active completed two 60-minute treadmill running sessions at 65% maximal intensity during low E2 (midfollicular menstrual phase) and high E2 (midluteal menstrual phase) hormonal conditions. Blood samples were collected prior to exercise, following supine rest, immediately post-, 30 min post-, and 24 hr post-exercise to determine changes in muscle biomarker. Resting blood samples confirmed appropriate E2 hormonal levels Results: CK concentrations increased following exercise and at 24 hr post-exercise were higher in the midfollicular phase (p<0.001). However, CK-MB concentrations were unaffected by E2 level or exercise (p=0.442). Conclusions: E2 levels influence the CK biomarkers response for skeletal but not cardiac muscle following prolonged aerobic exercise. These findings imply elevated E2 is protective of skeletal muscle from exercise-induced damage.