Associations of Physical Activity and Sedentary Time with Aortic Stiffness and Autonomic Function in Early Pregnancy.

Abstract

Rapid cardiovascular and autonomic adaptations occur during early pregnancy to accommodate augmented cardiac output and placental circulation, with inadequate adaptation associated with hypertensive pregnancy complications. Habitual physical activity (PA) and limiting time in sedentary behaviors (SED) may improve pregnancy-related vascular and autonomic function. The objective of this study was to examine the magnitude of the predicted associations between device-measured PA and SED with cardiovascular and autonomic biomarkers including aortic stiffness, blood pressure variability (BPV) and baroreflex sensitivity (BRS) in the first trimester of pregnancy. Pregnant women (N=92, 21-44 years of age) free from cardiovascular disease were assessed between 10⁰-12⁶ weeks gestation. Participants wore a thigh-mounted activPAL device for seven days to assess PA (light intensity and moderate-to-vigorous intensity) and SED. Aortic stiffness was measured by non-invasive applanation tonometry and expressed as carotid-femoral pulse wave velocity (cfPWV). Beat-to-beat blood pressure and R-R interval were synchronously recorded for 10 minutes via finger plethysmography and ECG to derive beat-to-beat BPV and spontaneous cardiovagal BRS (sequence method). In the entire group, neither PA or SED were related to cfPWV, BPV or BRS and this finding was similar in nulliparous and parous pregnant women. In stratified analyses, the association between moderate-to-vigorous-intensity PA and cfPWV differed by gestational age, such that this inverse association was only present in the 12^th week of gestation (β = -0.365, P=0.015). The present study indicates that PA and SED are not associated with aortic stiffness or autonomic function in the first trimester.