The effect of prescribed exercise volume on biomarkers of chronic stress in postmenopausal women: Results from the Breast Cancer and Exercise Trial in Alberta (BETA).
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ABSTRACT: There is epidemiologic and biologic evidence for a role of stress in breast cancer etiology and physical activity mitigates the negative effects of stress. We examined the potential for a dose-response relationship between two volumes of aerobic exercise and biomarkers of chronic stress in post-menopausal women. The Breast Cancer and Exercise Trial in Alberta is a randomized controlled trial with post-menopausal women randomized to either a MODERATE (150?min per week) or HIGH (300?min per week) volume of exercise over a one year intervention period. Fasting serum concentrations of cortisol, cortisone, corticosterone and 11-deoxycortisol at baseline, 12?months (the end of the intervention), and 24?months. Intention-to-treat analyses were performed using general linear models, adjusted for baseline biomarker concentrations. There were modest but non-statistically significant decreases in cortisol (HIGH: -4%, 95% CI: -7%, 2%; MODERATE: -1%, 95%: CI: -14%, 4%) and corticosterone (HIGH: -4%, 95% CI: -12%, 6%; MODERATE: -5%, 95% CI: -14%, 4%) concentrations for both exercise groups between baseline and 12?months, and no difference in cortisone concentrations. Intention-to-treat analysis of 386 (97%) participants showed no statistically significant group differences for changes in biomarker levels at 12?months. Between baseline and 12?months, there were no differences in cortisol or cortisone and, at 24?months all stress hormone levels increased to near-baseline levels with no significant differences between the two intervention groups.
SUBMITTER: Friedenreich CM
PROVIDER: S-EPMC6664156 | biostudies-literature | 2019 Sep
REPOSITORIES: biostudies-literature
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