title: The effect of estrogen on muscle damage biomarkers following prolonged aerobic exercise in eumenorrheic women.
abstract: This study assessed the influence of estrogen (E2) on muscle damage biomarkers [skeletal muscle - creatine kinase (CK); cardiac muscle - CK-MB] responses to prolonged aerobic exercise. Eumenorrheic women (n=10) who were physically active completed two 60-minute treadmill running sessions at ∼60-65% 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 hours post-exercise to determine changes in muscle biomarkers. Resting blood samples confirmed appropriate E2 hormonal levels Total CK concentrations increased following exercise and at 24 hours post-exercise were higher in the midfollicular low E2 phase (p<0.001). However, CK-MB concentrations were unaffected by E2 level or exercise (p=0.442) resulting in the ratio of CK-MB to total CK being consistently low in subject responses (i.e., indicative of skeletal muscle damage). Elevated E2 levels reduce the CK responses of skeletal muscle, but had no effect on CK-MB responses following prolonged aerobic exercise. These findings support earlier work showing elevated E2 is protective of skeletal muscle from exercise-induced damage associated with prolonged aerobic exercise.
authors.affiliation: Endocrine Section- Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: T
authors.initials: T
authors.lastname: Williams
authors.affiliation: Endocrine Section- Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: E
authors.initials: E
authors.lastname: Walz
authors.affiliation: Endocrine Section- Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Lane
authors.affiliation: Endocrine Section- Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: M
authors.initials: M
authors.lastname: Pebole
authors.affiliation: Endocrine Section- Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Hackney
keywords: creatine kinase; creatine kinase-MB; female gender; hormones; inflammation