Controlled breathing and pain: Respiratory rate and inspiratory loading modulate cardiovascular autonomic responses, but not pain

Sex differences in the reactivity of gastric myoelectrical activity and heart rate variability as putative psychophysiological markers in human pain research

Background

This study explored the potential of electrogastrography (EGG) and heart rate variability (HRV) as psychophysiological markers in experimental pain research related to the gut-brain axis. We investigated responses to the experience of pain from the visceral (rectal distension) and somatic (cutaneous heat) pain modalities, with a focus on elucidating sex differences in EGG and HRV responses.

Methods

In a sample of healthy volunteers (29 males, 43 females), EGG and ECG data were collected during a baseline and a pain phase. Data were analyzed for changes in gastric myoelectrical activity and cardiac autonomic regulation, with special attention to sex-specific patterns and correlations with perceptual responses to visceral and somatic pain stimuli, assessed by visual analogue scale ratings.

Results

Acute pain induced significant instability in EGG slow-wave frequency and amplitude, increased tachygastria, and decreased normogastric spectral power, without evidence of sex differences. HRV analyses revealed increases in SDNN, RMSSD, and pNN50 during pain, indicating sympathovagal regulation changes. While there were no significant sex differences in EGG responses, only female participants exhibited significant correlations between visceral pain unpleasantness and EGG alterations. HRV measures, particularly time-domain parameters, showed sex differences, independent of pain-induced autonomic reactivity.

Conclusion

The experience of pain in the lower abdominal region may induce impaired gastric motility. EGG and HRV are sensitive to acute pain and offer insight into pain mechanisms along the gut-brain axis. While EGG responses were consistent across sexes, HRV revealed sex-specific differences, suggesting that autonomic regulation and gastric motility may be modulated differently by pain and psychosocial factors. Further research in patients with chronic visceral pain is warranted.

Effect of a controlled diaphragmatic breathing session on perceived pain and state anxiety in people with chronic pain

Chronic pain conditions are frequently comorbid with anxiety problems. The controlled diaphragmatic breathing technique has been applied in both conditions. However, few studies have examined its efficacy in reducing perceived pain and state anxiety in the population with both pathologies. Thus, the study objective was to investigate the immediate effects of a single-session diaphragmatic breathing intervention on perceived pain and state anxiety in a group of people with chronic pain. We analyzed the influence of sociodemographic variables, dispositional anxiety, average pain during the last week, respiratory rate, and inhalation/exhalation ratio. The sample comprised 169 people with chronic pain from Spain and Poland who were evaluated before and after performing an online controlled diaphragmatic breathing task. The Wilcoxon test showed significant decreases in state anxiety and perceived pain. Linear regression analyses revealed an association between dispositional anxiety and pretest/posttest differences in state anxiety, as well as an association between both average pain in the last week and nationality and pretest/posttest differences in perceived pain. We conducted an exploratory analysis of the differences between both countries in the study variables. We discuss the results and the relevance of further studies on the efficacy of this technique in reducing perceived pain and state anxiety.

Mindful Breathing as an Adjunctive Approach to Chronic Low Back Pain Management: A Scoping Review

BACKGROUND

Chronic low back pain (CLBP) is a common and challenging condition. This scoping review explores the literature on mindful breathing's role in managing CLBP, either alone or alongside physiotherapy.

METHODS

A thorough database search identified studies on mindful breathing and CLBP. Various study designs, from descriptive to randomized controlled trials, were included.

RESULTS

Reviewed studies suggest that mindful breathing can improve body awareness and patients with CLBP. In a randomized controlled trial both mindful breathing and physiotherapy groups reported significant pain reduction (VAS: -2.7 mindful breathing, VAS: -2.4 physiotherapy) and improved quality of life (SF-36*: +14.9 mindful breathing, SF-36: +21.0 physiotherapy). Yu et al. found that combining mindful breathing with core stability exercises yielded superior outcomes (ORR* = 96.67%) compared to core exercises alone (ORR = 73.33%).

CONCLUSIONS

Mindful breathing holds promise for chronic low back pain management, with studies revealing pain reduction and improved quality of life. Combining it with core stability exercises enhances outcomes. However, standardized protocols are lacking, limiting clinical use. Future research should focus on precise guidelines for integration into practice. Mindful breathing offers a holistic approach to pain management.

Development of audio-guided deep breathing and auditory Go/No-Go task on evaluating its impact on the wellness of young adults: a pilot study

OBJECTIVES

Numerous studies indicate that deep breathing (DB) enhances wellbeing. Multiple deep breathing methods exist, but few employ audio to reach similar results. This study developed audio-guided DB and evaluated its immediate impacts on healthy population via self-created auditory Go/No-Go task, tidal volume changes, and psychological measures.

METHODS

Audio-guided DB with natural sounds to guide the DB was developed. Meanwhile, audio-based Go/No-Go paradigm with Arduino was built to measure the attention level. Thirty-two healthy young adults (n=32) were recruited. Psychological questionnaires (Rosenberg's Self-Esteem Scale (RSES), Cognitive and Affective Mindfulness Scale-Revised (CAMS-R), Perceived Stress Scale (PSS)), objective measurements with tidal volume and attention level with auditory Go/No-Go task were conducted before and after 5 min of DB.

RESULTS

Results showed a significant increment in tidal volume and task reaction time from baseline (p=0.003 and p=0.033, respectively). Significant correlations were acquired between (1) task accuracy with commission error (r=-0.905), (2) CAMS-R with task accuracy (r=-0.425), commission error (r=0.53), omission error (r=0.395) and PSS (r=-0.477), and (3) RSES with task reaction time (r=-0.47), task accuracy (r=-0.362), PSS (r=-0.552) and CAMS-R (r=0.591).

CONCLUSIONS

This pilot study suggests a link between it and young adults' wellbeing and proposes auditory Go/No-Go task for assessing attention across various groups while maintaining physical and mental wellness.

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

Resonance breathing (RB) has been shown to benefit health and performance within clinical and non-clinical populations. This is attributed to its baroreflex stimulating effect and the concomitant increase in cardiac vagal activity (CVA). Hence, developing methods that strengthen the CVA boosting effect of RB could improve its clinical effectiveness. Therefore, we assessed whether supplementing RB with coherent pelvic floor activation (PRB), which has been shown to entrain the baroreflex, yields stronger CVA than standard RB. N = 32 participants performed 5-min of RB and PRB, which requires to recruit the pelvic floor during the complete inspiratory phase and release it at the initiation of the expiration. CVA was indexed via heart rate variability using RMSSD and LF-HRV. PRB induced significantly larger RMSSD (d = 1.04) and LF-HRV (d = 0.75, ps < .001) as compared to RB. Results indicate that PRB induced an additional boost in CVA relative to RB in healthy individuals. However, subsequent studies are warranted to evaluate whether these first findings can be replicated in individuals with compromised health, including a more comprehensive psychophysiological assessment to potentially elucidate the origin of the observed effects. Importantly, longitudinal studies need to address whether PRB translates to better treatment outcomes.

Confounding effects of heart rate, breathing rate, and frontal fNIRS on interoception

Recent studies have established that cardiac and respiratory phases can modulate perception and related neural dynamics. While heart rate and respiratory sinus arrhythmia possibly affect interoception biomarkers, such as heartbeat-evoked potentials, the relative changes in heart rate and cardiorespiratory dynamics in interoceptive processes have not yet been investigated. In this study, we investigated the variation in heart and breathing rates, as well as higher functional dynamics including cardiorespiratory correlation and frontal hemodynamics measured with fNIRS, during a heartbeat counting task. To further investigate the functional physiology linked to changes in vagal activity caused by specific breathing rates, we performed the heartbeat counting task together with a controlled breathing rate task. The results demonstrate that focusing on heartbeats decreases breathing and heart rates in comparison, which may be part of the physiological mechanisms related to "listening" to the heart, the focus of attention, and self-awareness. Focusing on heartbeats was also observed to increase frontal connectivity, supporting the role of frontal structures in the neural monitoring of visceral inputs. However, cardiorespiratory correlation is affected by both heartbeats counting and controlled breathing tasks. Based on these results, we concluded that variations in heart and breathing rates are confounding factors in the assessment of interoceptive abilities and relative fluctuations in breathing and heart rates should be considered to be a mode of covariate measurement of interoceptive processes.

Effects of Slow Deep Breathing on Acute Clinical Pain in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Slow deep breathing (SDB) may help patients with acute pain. The primary aim of this systematic review and meta-analysis is to investigate the effects of SDB on acute pain. Secondary aims include investigating the effects of SDB on acute pain-related physical and emotional functioning. An a priori protocol was registered and a database search was conducted by a reference librarian. Randomized controlled trials (RCT) were eligible for inclusion and exclusion criteria included studies of SDB for non-pain indications and studies that applied SDB as a component of an encompassing intervention. The risk or bias was assessed using the Cochrane Collaboration's revised tool for assessing risk of bias in randomized trials. Meta-analysis was conducted using the random effects model. A total of 11 968 studies were screened and seven RCTs met inclusion criteria; five were judged to have low risk of bias. Meta-analysis of post-intervention pain scores demonstrated that SDB was associated with significantly lower pain scores compared with a control group, but with high levels of heterogeneity. Subgroup analyzes demonstrated that trials of burn pain were associated with a larger reduction in pain which partially explains the heterogeneity. Very low certainty evidence suggests that SDB may reduce acute pain intensity. Further research is needed to identify patients who are candidates for SDB and determine the best approach to deliver this therapy.