Abstract
Background
Cardiovagal baroreflex gain (cBRG) reflects an individual's ability to buffer swings
in blood pressure. It is not well understood how this mechanism is influenced by physical
activity in pregnancy. Because pregnant women tend to engage in low levels of moderate-to-vigorous
physical activity (MVPA) and high levels of sedentary behaviour, we sought to determine
the influence of MVPA and sedentary behaviour on cBRG and mean arterial pressure (MAP)
in pregnancy.
Methods
Fifty-eight third trimester (31.9 ± 3.0 weeks) normotensive pregnant women (31.2 ±
2.8 years) were tested. Heart rate (electrocardiogram) and blood pressure (systolic
blood pressure and MAP; finger photoplethysmography) were collected on a beat-by-beat
basis, and averaged over 3 minutes of rest. Spontaneous cBRG was calculated as the
slope of the relationship between fluctuations in systolic blood pressure and heart
rate. Objective measures of MVPA and sedentary behaviour were collected over a 7-day
period using an ActiGraph accelerometer (model wGTX3-BT; ActiGraph LLC, Pensacola,
FL).
Results
Participants spent 67.5 ± 7.9% of waking hours engaged in sedentary behaviour, and
performed 68.6 ± 91.9 minutes of MVPA per week. Sedentary behaviour was not related
to cBRG (r = −0.035; P = 0.793) or MAP (r = −0.033; P = 0.803). However, MVPA was positively associated with cBRG (r = 0.315; P = 0.016), but not MAP (r = −0.115; P = 0.389). The association between MVPA and cBRG remained significant after controlling
for age, pre-pregnancy body mass index, gestational age, and wear time (r = 0.338; P = 0.013), indicating that women who engaged in greater amounts of MVPA showed increased
cBRG.
Conclusions
Our data suggest that increased MVPA, but not necessarily reduced sedentary behaviour,
might be beneficial for reflex control of blood pressure during pregnancy.
Résumé
Contexte
La sensibilité (gain) du baroréflexe cardiovagal (SBRc) reflète la capacité individuelle
d’amortir les variations de la pression sanguine. L’influence que l’activité physique
peut avoir sur ce mécanisme durant la grossesse n’est pas entièrement élucidée. Étant
donné que les femmes enceintes ont tendance à pratiquer peu d’activités physiques
modérées ou vigoureuses (APMV) et à adopter des comportements caractérisés par un
degré élevé de sédentarité, nous avons cherché à déterminer l’influence des APMV et
des comportements sédentaires sur la SBRc et la pression artérielle moyenne (PAM)
pendant la grossesse.
Méthodologie
Cinquante-huit femmes enceintes (31,2 ± 2,8 ans) normotendues parvenues au troisième
trimestre de leur grossesse (31,9 ± 3,0 semaines) ont été les sujets de notre étude.
La fréquence cardiaque (électrocardiogramme) et la pression artérielle (pression artérielle
systolique et PAM; photopléthysmographie digitale) ont été mesurées à chaque battement
cardiaque, et leur moyenne établie sur 3 minutes au repos. Les valeurs de la SBRc
spontanée, correspondant à la pente de la relation entre les fluctuations de la pression
artérielle systolique et la fréquence cardiaque, ont été notées. Des mesures objectives
des APMV et des comportements sédentaires ont été recueillies sur une période de 7
jours à l’aide d’un accéléromètre ActiGraph (modèle wGTX3-BT; ActiGraph LLC, Pensacola,
FL).
Résultats
Les participantes ont consacré 67,5 ± 7,9 % du temps d’éveil à des comportements sédentaires
et 68,6 ± 91,9 minutes à des APMV chaque semaine. Les comportements sédentaires n’étaient
liés ni à la SBRc (r = −0,035; p = 0,793) ni à la PAM (r = −0,033; p = 0,803). Toutefois, les APMV étaient positivement associées à la SBRc (r = 0,315; p = 0,016), mais pas à la PAM (r = −0,115; p = 0,389). L’association entre les APMV et la SBRc est demeurée significative après
l’ajustement en fonction de l’âge, de l’indice de masse corporelle avant la grossesse,
de l’âge gestationnel et du temps de port (r = 0,338, p = 0,013), ce qui indique un accroissement de la SBRc chez les femmes ayant pratiqué
plus d’APMV.
Conclusions
Nos données permettent de penser que la pratique accrue d’APMV, mais pas nécessairement
une diminution des comportements sédentaires, pourrait avoir un effet favorable sur
le réflexe de régulation de la pression artérielle durant la grossesse.
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Article info
Publication history
Published online: February 03, 2018
Accepted:
January 9,
2018
Received:
September 8,
2017
Footnotes
See page 490 for disclosure information.
Identification
Copyright
© 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
