Effect of Prenatal Yoga on Heart Rate Variability and Cardio-Respiratory Synchronization: A Prospective Cohort Study

Abstract

The objective was to assess the effects of prenatal yoga on heart rate variability (HRV) and cardio-respiratory synchronization, used as proxies of autonomic nervous system activity. Sixty-nine healthy pregnant women were included; 33 in a yoga group attending at least one 90-min yoga class weekly throughout pregnancy, and 36 controls not involved in formal pregnancy exercise programs. Measurements of the time domain (SDNN, standard deviation of regular R-R intervals, and RMSSD, square root of mean squared differences of successive R-R intervals) and frequency domain (ln(LF/HF), natural logarithm of low-frequency to high-frequency power) HRV indices, as well as cardio-respiratory synchronization indexes were performed once per trimester before and after yoga or 30-min moderate-intensity walk. A statistical comparison was performed using a three-way analysis of the variance (p < 0.05 significant). Both the time domain and frequency domain HRV indices showed significant shifts towards parasympathetic dominance following yoga when compared to the controls throughout pregnancy (p = 0.002 for SDNN, p < 0.001 for RMSSD, and p = 0.006 for ln(LF/HF), respectively). There was a statistically non-significant trend towards higher synchronization between respiratory frequency and heart rate following yoga vs. controls (p = 0.057). Regular prenatal yoga was associated with enhanced parasympathetic activation persisting throughout pregnancy.

Effect of Prenatal Yoga versus Moderate-Intensity Walking on Cardiorespiratory Adaptation to Acute Psychological Stress: Insights from Non-Invasive Beat-to-Beat Monitoring

“…There was no significant difference in the maternal body mass index (BMI) between the yoga group and controls (24.06 ± 3.55 vs. 23.74 ± 3.43 kg/m 2 , p = 0.693). Women practicing yoga were older (28.6 ± 3.9 vs. 31.3 ± 3.5 years, p = 0.005) and more often nulliparous (26 (79%) vs. 18 (50%), p = 0.001) [ 19 ].…”

“…The study was approved by the Institutional Review Board of the University Medical Center Maribor [ 22 ] and the Slovenian National Medical Ethics Committee (project number 0120-575/2018/5, approved on 22 February 2019). The detailed participant enrollment procedure and study flow have been published previously [ 19 ] (Clinicaltrials.gov registration: NCT04476368).…”

“…Raw data were exported to MATLAB ® (The Math Works, Inc., Natick, MA, USA) data format for further analysis. A semi-automatic artifact-handling software, described in detail in our previous publications, was used for artifact handling of the continuous recordings [ 19 , 24 ].…”

“…The maternal cardiovascular system undergoes profound changes during pregnancy and the autonomic nervous system plays a central role in cardiovascular adaptation to pregnancy-related hemodynamic changes [ 14 , 15 , 16 , 17 , 18 ]. Our group has recently reported enhanced parasympathetic activation at rest throughout pregnancy associated with regular yoga practice [ 19 ].…”

“…The impact of yoga on acute stress response in pregnancy has, however, not been studied yet. This manuscript presents a secondary analysis of data collected within a prospective cohort study of pregnant women practicing yoga regularly from the first trimester [ 19 ]. Data on alterations of heart rate variability (HRV) and cardio-respiratory phase synchronization during and immediately following acute stress response to mental challenge are original and have not been published previously.…”