Squeeze the beat: Enhancing cardiac vagal activity during resonance breathing via coherent pelvic floor recruitment

The cardiac correlates of feeling safe in everyday life: A Bayesian replication study

BACKGROUND

Feeling safe and secure has been proposed to dampen autonomic arousal and buffer threat responses. In a previous study, we could show that momentary ratings of subjective safety were associated with elevated heart rate variability (specifically, root mean square of successive differences; RMSSD) and lower heart rate in everyday life, thus suggesting a health-protective role of feeling safe.

METHODS

This study aimed to replicate this effect in a sample of N = 79 adults, applying Bayesian statistics with prior effects of the original study.

RESULTS

Using an ecological momentary assessment (EMA) across three days we could replicate the effect of lower heart rate and higher RMSSD in moments when participants felt more safe. In accordance with the original study, we could also show that the effect on heart rate were independent of RMSSD, thus suggesting a contribution of sympathetic activity to this effect.

CONCLUSION

The findings confirm the connection between momentary feelings of safety and cardiac regulation, thus substantiating research on the health-protective role of psychological safety.

Cardiac vagal activity is associated with gut-microbiome patterns in women-An exploratory pilot study

Introduction

A functional reciprocity between the gut microbiome and vagal nerve activity has been suggested, however, human studies addressing this phenomenon are limited.

Methods

Twenty-four-hour cardiac vagal activity (CVA) was assessed from 73 female participants (aged 24.5 ± 4.3 years). Additionally, stool samples were subjected to 16SrRNA gene analysis (V1–V2). Quantitative Insights Into Microbial Ecology (QIIME) was used to analyse microbiome data. Additionally, inflammatory parameters (such as CRP and IL-6) were derived from serum samples.

Results

Daytime CVA correlated significantly with gut microbiota diversity (r_sp = 0.254, p = 0.030), CRP (r_sp = −0.348, p = 0.003), and IL-6 (r_sp = −0.320, p = 0.006). When the group was divided at the median of 24 h CVA (Mdn = 1.322), the following features were more abundant in the high CVA group: Clostridia (Linear discriminant analysis effect size (LDA) = 4.195, p = 0.029), Clostridiales (LDA = 4.195, p = 0.029), Lachnospira (LDA = 3.489, p = 0.004), Ruminococcaceae (LDA = 4.073, p = 0.010), Faecalibacterium (LDA = 3.982, p = 0.042), Lactobacillales (LDA = 3.317, p = 0.029), Bacilli (LDA = 3.294, p = 0.0350), Streptococcaceae (LDA = 3.353, p = 0.006), Streptococcus (LDA = 3.332, p = 0.011). Based on Dirichlet multinomial mixtures two enterotypes could be detected, which differed significantly in CVA, age, BMI, CRP, IL-6, and diversity.

Conclusions

As an indicator of gut-brain communication, gut microbiome analysis could be extended by measurements of CVA to enhance our understanding of signalling via microbiota-gut-brain-axis and its alterations through psychobiotics.