Abstract Body: Background: Associations of physical activity (PA) and sedentary behavior (SB) with biomarkers of cardiac stress could have implications for cardiovascular resiliency in aging women but are understudied.
Methods: Postmenopausal women (50-79 years old at Women’s Health Initiative enrollment) (a) without known CHD, (b) with available self-reported usual PA and SB information, and (c) with available blood biomarkers for high-sensitivity C-reactive protein (hsCRP mg/L; inflammation), tissue plasminogen activator (tPA ng/mL; fibrinolysis), N-terminal pro-brain natriuretic protein (NT-proBNP pg/mL; volume overload), and plasminogen activator inhibitor-1 (PAI-1 pg/mL; thrombosis/endothelial dysfunction) were included in this cross-sectional analysis (n=3,537 for hsCRP, tPA, NT-proBNP; n = 2,460 PAI-1). Adjusted means were estimated from linear regression models. All data was ascertained at study enrollment.
Results: Controlling for age, race-ethnicity, history of stroke, heart failure, treated diabetes or hypertension, smoking, and postmenopausal hormone use, adjusted mean biomarker concentrations across incremental walking categories (0, >0-3.5, >3.5-8.33, >8.33 MET-hr/wk) were: hsCRP 4.1, 3.7, 3.2, 2.5, trend P<.001; NT-proBNP 162.9, 155.1, 148.2, 151.3, trend P=.05; tPA 8.9, 9.2, 8.3, 8.0, trend P=.01; PAI-1 16691, 16896, 15717, 14672, trend P<.001 (Figures 1 & 2). Similar patterns were observed across strenuous activity categories, aside from NT-proBNP. Across incremental categories of SB (<4.6, 4.6-8.5, >8.5 hr/day) positive associations were seen for adjusted mean hsCRP 3.4, 3.6, 3.9, trend P<.01; tPA 8.2, 8.9, 9.9, trend P=.03; PAI-1 15552, 16407, 16639, trend P=.05. In stratified analysis, inverse associations were observed regardless of comorbid status (prevalent diabetes, hypertension, heart failure, or cancer). Associations were attenuated but significant among older women, and associations of PA measures with hsCRP were stronger in those with high BMI (30+ kg/m²).
Conclusion: In this cross-sectional study of postmenopausal women, higher levels of walking and strenuous PA were associated with lower concentrations of biomarkers related to inflammation (hsCRP), fibrinolysis (tPA), and thrombosis/endothelial dysfunction (PAI-1), while higher SB was positively associated with elevated levels. The findings highlight the role of PA in promoting cardiovascular resiliency during aging, and underscore the adverse impact of prolonged SB.