Maternal cardioautonomic responses during and following exercise throughout pregnancy

Abstract

Blood pressure regulation during pregnancy is poorly understood. Cardiovagal baroreflex gain (BRG) is an important contributor to blood pressure regulation via its influence on heart-rate. Heart-rate fluctuations occur in response to various physiological stimuli and can be measured using heart-rate variability (HRV). It is unclear how these mechanisms operate during pregnancy, particularly related to exercise. We examined BRG and HRV prior to, during, and following prenatal exercise. Forty-three pregnant (n=10 first trimester [TM1], n=17 second trimester [TM2]; n=16 third trimester [TM3]) and 20 non-pregnant (NP) women underwent an incremental peak exercise test. Beat-by-beat blood pressure (photoplethysmography) and heart-rate (lead II ECG) were measured throughout. BRG (slope of the relationship between fluctuations in systolic blood pressure and R-R interval) and HRV (root mean square of the successive differences; RMSSD) were assessed at rest, during steady-state exercise (EX), and during active recovery. BRG decreased with gestation and was lower in TM3 compared to NP (17.9±6.9 vs 24.8±7.4 ms/mmHg, p=0.017). BRG was reduced during EX in all groups. Resting HRV (RMSSD) also decreased with gestation and was lower in TM3 compared to NP (29±17 vs 48±20 ms, p<0.001). RMSSD was blunted during EX for all groups compared to REST. During active recovery, RMSSD was further blunted compared to EX in NP, but not during pregnancy (TM1, TM2, and TM3). Compared to non-pregnant controls, pregnant women had lower BRG and HRV at rest, but comparable cardioautonomic control during both exercise and active recovery following peak exercise.

Cardiopulmonary exercise testing during pregnancy

“…Skipping a cool down entirely could result in adverse effects in some individuals. By immediately halting exercise after an intense bout, the cardiovascular system will experience a rapid drop in heart rate while still supporting exercise‐induced vasodilation leading to a decline of blood pressure causing potential dizziness or fainting (Purdy et al, 2018; Senitko, Charkoudian, & Halliwill, 2002). An adequate cool down aids in the recovery of the cardiovascular system, and decreases the risk of exponential drops in blood pressure.…”

“…When CPX last longer than 12 minutes external factors, such as peripheral or psychological fatigue, can impact an individual's performance and underestimate their aerobic capacity (Balady et al, 2010a(Balady et al, , 2010b. Unless there is a clinical indication to extend exercise stages, the majority of women are able to tolerate 1-minute stages even into late pregnancy (Matenchuk et al, 2019;Purdy et al, 2018). It is also important to ensure that the CPX assessor is aware of the cardiac adaptations that occur during pregnancy (i.e., increase in resting heart rate that can impact maximal heart rate and heart rate reserve equations (Meah et al, 2016;Robson et al, 1989)) and follow pregnancy target heart rate guidelines when identifying the intensity at which an individual is working during a CPX (Mottola et al, 2018).…”

Effects of High-Fat Diet and Exercise Intervention on the Metabolism Regulation of Infant Mice

“…It also improves the function of mitochondria and increases the oxidative metabolism of fatty acids while controlling blood glucose and reducing the inflammatory response during pregnancy [13]. Several physiological benefits of exercise during pregnancy have been proposed previously [14][15][16][17][18][19][20]. A low-to moderate-intensity exercise does not exert any negative impact on the developing fetus [21].…”

Avaliação do comportamento cardiovascular de gestantes durante o repouso e na fase de relaxamento de um protocolo aquático terapêutico de moderada intensidade

“…Durante o primeiro e segundo trimestre, a pressão arterial sistólica (PAS) costuma cair ou não se alterar, enquanto a pressão arterial diastólica (PAD) pode apresentar um declínio de 10 a 15 mmHg. Contudo, a partir do terceiro trimestre, a PA sobe até os níveis pré-gravídicos [1][2][3][4]. O Sistema Nervoso Autônomo (SNA) tem um papel importante nessas adaptações do sistema cardiovascular durante a gravidez, sobre o qual é notada uma modulação vagal alta e simpática baixa no primeiro trimestre da gestação, ao passo que, no final da gravidez, ocorre uma modulação vagal baixa e simpática alta [1,5].…”