Can Slow Deep Breathing Reduce Pain? An Experimental Study Exploring Mechanisms

To what degree patient-reported symptoms of central sensitization, kinesiophobia, disability, sleep, and life quality associated with 24-h heart rate variability and actigraphy measurements?

OBJECTIVES

Chronic musculoskeletal pain is associated with decreased parasympathetic and increased sympathetic activity in the autonomic nervous system. The objective of this study was to determine the associations between objective measures of heart rate variability (a measure of autonomic nervous system function), actigraphy (a measure of activity and sleep quality), respiration rates, and subjective patient-reported outcome measures (PROMs) of central sensitization, kinesiophobia, disability, the effect of pain on sleep, and life quality.

METHODS

Thirty-eight study subjects were divided into two subgroups, including low symptoms of central sensitization (n = 18) and high symptoms of central sensitization (n = 20), based on patient-reported scores on the Central Sensitization Inventory (CSI). Heart rate variability (HRV) and actigraphy measurements were carried out simultaneously in 24 h measurement during wakefulness and sleep.

RESULTS

A decrease in HRV during the first 2 h of sleep was stronger in the low CSI subgroup compared to the high CSI subgroup. Otherwise, all other HRV and actigraphy parameters and subjective measures of central sensitization, disability, kinesiophobia, the effect of pain on sleep, and quality of life showed only little associations.

DISCUSSION

The high CSI subgroup reported significantly more severe symptoms of disability, kinesiophobia, sleep, and quality of life compared to the low CSI subgroup. However, there were only small and nonsignificant trend in increased sympathetic nervous system activity and poorer sleep quality on the high central sensitization subgroup. Moreover, very little differences in respiratory rates were found between the groups.

Protocol of identical exercise programs with and without specific breathing techniques for the treatment of chronic non-specific low back pain: randomized feasibility trial with two-month follow-up

BACKGROUND

Chronic low back pain (CLBP) is a leading cause of disability globally. Exercise therapies are one of the commonly prescribed treatment options for CLBP. The specific exercise therapies for CLBP most commonly target movement dysfunction, but seldom brain-based pain modulation. Exercise therapies with specific breathing techniques (SBTs) have been shown to influence and enhance brain-based structural and functional pain modulation.

AIMS AND OBJECTIVES

To assess the feasibility of the SBTs protocol, eligibility criteria, randomization, and dropout rates. To quantify the changes in patient outcome measures and choose the most relevant measure for larger-scale study. To quantify self-adherence levels to home exercise and monitor and record possible pain medication and other treatment modality usage, and adverse events during exercise.

DESIGN

A parallel randomised analyst-blinded feasibility trial with two-month follow-up.

OUTCOME MEASURES

Feasibility related to aims and objectives. Multiple pain- and health-related patient-reported outcome measures of pain intensity, disability, central sensitization, anxiety, kinesiophobia, catastrophising, self-efficacy, sleep quality, quality of life, and health and well-being status. Exercise adherence, pain medication and other treatment modality usage, and possible adverse events related to exercises will be monitored and recorded.

METHODS

Thirty participants will be randomized to movement control exercise with SBTs (15 subjects in experimental group) or movement control exercise without SBTs (15 subjects in control group) in private chiropractic practice setting with two-month follow-up. Trial registration number; NCT05268822.

DISCUSSION

The clinical difference in effectiveness between practically identical exercise programs in uniform study settings with or without SBTs has not been studied before. This study aims to inform feasibility and help determine whether progression to a full-scale trial is worthwhile.

Conscious connected breathing with breath retention intervention in adults with chronic low back pain: protocol for a randomized controlled pilot study

BACKGROUND

Chronic pain is a major source of human suffering, and chronic low back pain (cLBP) is among the most prevalent, costly, and disabling of pain conditions. Due to the significant personal and societal burden and the complex and recurring nature of cLBP, self-management approaches that can be practiced at home are highly relevant to develop and test. The respiratory system is one of the most integrated systems of the body, and breathing is bidirectionally related with stress, emotion, and pain. Thus, the widespread physiological and psychological impact of breathing practices and breathwork interventions hold substantial promise as possible self-management strategies for chronic pain. The primary aim of the current randomized pilot study is to test the feasibility and acceptability of a conscious connected breathing with breath retention intervention compared to a sham control condition.

METHODS

The rationale and procedures for testing a 5-day conscious connected breathing with breath retention intervention, compared to a deep breathing sham control intervention, in 24 adults (18-65 years) with cLBP is described. Both interventions will be delivered using standardized audio recordings and practiced over 5 days (two times in-person and three times at-home), and both are described as Breathing and Attention Training to reduce possible expectancy and placebo effects common in pain research. The primary outcomes for this study are feasibility and acceptability. Feasibility will be evaluated by determining rates of participant recruitment, adherence, retention, and study assessment completion, and acceptability will be evaluated by assessing participants' satisfaction and helpfulness of the intervention. We will also measure other clinical pain, psychological, behavioral, and physiological variables that are planned to be included in a follow-up randomized controlled trial.

DISCUSSION

This will be the first study to examine the effects of a conscious connected breathing with breath retention intervention for individuals with chronic pain. The successful completion of this smaller-scale pilot study will provide data regarding the feasibility and acceptability to conduct a subsequent trial testing the efficacy of this breathing self-management practice for adults with cLBP.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier NCT04740710 . Registered on 5 February 2021.

Breathing Exercises for Pain Management in Cancer Survivors: A Systematic Review

OBJECTIVES

Unmanaged pain significantly affects cancer survivors' quality of life. Nurses should play a significant role in pain management through non-pharmacological interventions. This review aims to explore the efficacy and safety of breathing exercises for pain management in all cancer survivors.

DESIGN

A systematic review.

DATA SOURCES

Thirteen databases, including PubMed, EMBase, CENTRAL, MEDLINE, CINAHL, JBI, Science Direct, Scopus, SocINDEX, Web of Science, PsycINFO, CNKI, and Wan Fang, were searched from inception to May, 2021.

REVIEW/ANALYSIS METHODS

Studies that focused on the efficacy of breathing exercises for pain management, regardless of the age of the cancer survivors, were included. Cochrane tools were used for the quality appraisal of the included studies. Because of the limited number of studies, descriptive data analysis was used to summarize the results.

RESULTS

Ten studies were included. Slow pursed lip breathing showed benefits for post-surgical pain. Contradictory findings were identified in the Enhanced Recovery After Surgery for post-surgical pain. Slow deep breathing and Hey-Hu regular breathing techniques were effective for pain management in pediatric cancer patients. The Active Cycle of Breathing Technique and five-minute mindful breathing did not have any statistically significant effects on pain relief. Quality of life was measured in three studies, with some improvement. Only one study addressed adverse events and reported that no adverse events occurred.

CONCLUSIONS

Breathing exercises may be a promising approach to pain relief in cancer survivors. However, more rigorously designed studies are required to establish the evidence.

The Effectiveness of Manual Therapy in the Cervical Spine and Diaphragm, in Combination with Breathing Reeducation Exercises, in Patients with Non-Specific Chronic Neck Pain: Protocol for Development of Outcome Measures and a Randomized Controlled Trial

Until now, non-specific chronic neck pain has mainly been considered as a musculoskeletal system dysfunction, with associated psychological involvement due to its prolonged or recurrent nature. However, patients with non-specific chronic neck pain frequently additionally exhibit respiratory dysfunction. Emerging evidence suggests that addressing the respiratory dysfunction in these patients will provide additional therapeutic benefits in musculoskeletal and respiratory-related outcomes for several reasons (biomechanical, biochemical, and psychological). Motor control dysfunction of the muscles surrounding the spine (diaphragm included) negatively affects the mechanics and biochemistry of breathing (pH-homeostasis). An impaired and ineffective breathing pattern has been recognized as the primary source of many unexplained symptoms (anxiety, depression, confusion, chest pain, hypocapnia, and breathlessness) in patients with non-specific chronic neck pain. The proposed protocol’s purpose is dual: to assess the relative effectiveness of manual therapy in the cervical spine and the diaphragm, in combination with breathing reeducation exercises, along with cervical spine manual therapy or usual physical therapy care on the underlying dysfunctions in patients with non-specific chronic neck pain via a randomized controlled clinical trial, and to validate part of the outcome measures. Several musculoskeletal and respiratory dysfunction outcomes will be employed to delimit the initial extent and level of dysfunction and its resolution with the treatments under study.

Session of yoga, with and without slow (Ujjayi) breathing, reduces anxiety; no change on acute pain sensitivity and endogenous pain modulation

OBJECTIVES

Yoga is an increasingly popular mode of exercise that boasts health promoting effects including pain relief. A single bout of exercise induces a reduced sensitivity to noxious heat, but the mechanism for this effect and whether it occurs after a single session of yoga is unexplored. The primary aim of this study was to test, using a post-test only between-subjects design, main and interactive effects of yoga and slow breathing on both sensitivity to heat pain and endogenous pain modulation processing in healthy young women DESIGN: Fifty-four women were block randomized into one of four conditions: yoga with slow breathing instructions (Vinyasa), yoga with no breathing instructions, seated rest with slow breathing instructions and seated rest with no breathing instructions. The conditions were completed alone is a small room in which participant followed video-based instructions and models. The yoga was perceived as low-to-moderate intensity.

RESULTS

Two factor ANOVA demonstrated no significant association between yoga postures and slow breathing, and there was no significant interaction observed for sensitivity to heat pain or endogenous pain modulation. These findings were unchanged in ANCOVAs that controlled for four potential confounding variables: post-condition reduction in systolic blood pressure or state anxiety, pain induced by the conditions and expectations. Compared to the non-yoga conditions, participant in yoga conditions resulted in a significant reduction in state anxiety scores.

CONCLUSIONS

It is concluded that a single session of low-to-moderate intensity yoga with, or without slow breathing, reduces state anxiety but has no effect on heat pain sensitivity or endogenous pain modulation.

Effect of slow, deep breathing on visceral pain perception and its underlying psychophysiological mechanisms

BACKGROUND

Studies using somatic pain models have shown the hypoalgesic effects of slow, deep breathing. We evaluated the effect of slow, deep breathing on visceral pain and explored putative mediating mechanisms including autonomic and emotional responses.

METHODS

Fifty-seven healthy volunteers (36 females, mean age = 22.0 years) performed controlled, deep breathing at a slow frequency (6 breaths per minute), controlled breathing at a normal frequency (14 breaths per minute; active control), and uncontrolled breathing (no-treatment control) in randomized order. Moderate painful stimuli were given during each condition by delivering electrical stimulation in the distal esophagus. Participants rated pain intensity after each stimulation. Heart rate variability and self-reported arousal were measured during each condition.

KEY RESULTS

Compared to uncontrolled breathing, pain intensity was lower during slow, deep breathing (Cohen's d = 0.40) and normal controlled breathing (d = 0.47), but not different between slow, deep breathing and normal controlled breathing. Arousal was lower (d = 0.53, 0.55) and heart rate variability was higher (d = 0.70, 0.86) during slow, deep breathing compared to the two control conditions. The effect of slow, deep breathing on pain was not mediated by alterations in heart rate variability or arousal but was moderated by pain catastrophizing.

CONCLUSIONS AND INFERENCES

Slow, deep breathing can reduce visceral pain intensity. However, the effect is not specific to the slow breathing frequency and is not mediated by autonomic or emotional responses, suggesting other underlying mechanisms (notably distraction). Whether a long-term practice of slow, deep breathing can influence (clinical) visceral pain warrants to be investigated.

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.

Heart Rate Variability and Pain: A Systematic Review

Background and Objective: Heart rate variability (HRV) as an index of the autonomic nervous system appears to be related to reactivity to experimental pain stimuli. HRV could better explain the contributions of sympathetic and parasympathetic activity response to nociceptive stimulation. The aim of this study was to systematically review and synthesize the current evidence on HRV in relation to the experience of pain in experimental tasks. Databases and Data Treatment: Studies indexed in the PubMed, PsycINFO, MEDLINE, WebOfScience, and Scopus databases were reviewed for eligibility. Studies on the autonomic response (i.e., HRV) to experimentally induced pain in healthy adults were included. Different methods of pain induction were considered (e.g., thermal, pressure, and electrical). Data were synthesized considering the association between HRV and both pain induction and subjective measures of pain. Results: Seventy-one studies were included. The results underline significant change in both the sympathetic and parasympathetic autonomic nervous systems during the painful stimulation independent of the pain induction method. The autonomic reaction to pain could be affected by several factors, such as sex, age, body mass index, breathing patterns, the intensity of the stimulation, and the affective state. Moreover, an association between the autonomic nervous system and the subjective experience of pain was found. Higher parasympathetic activity was associated with better self-regulation capacities and, accordingly, a higher pain inhibition capacity. Conclusions: HRV appears to be a helpful marker to evaluate nociceptive response in experimentally induced pain. Future studies are also needed in clinical samples to understand better the interindividual changes of autonomic response due to pain stimuli.

Slow-Paced Breathing: Influence of Inhalation/Exhalation Ratio and of Respiratory Pauses on Cardiac Vagal Activity

Slow-paced breathing has been shown to enhance the self-regulation abilities of athletes via its influence on cardiac vagal activity. However, the role of certain respiratory parameters (i.e., inhalation/exhalation ratio and presence of a respiratory pause between respiratory phases) still needs to be clarified. The aim of this experiment was to investigate the influence of these respiratory parameters on the effects of slow-paced breathing on cardiac vagal activity. A total of 64 athletes (27 female; Mage = 22, age range = 18–30 years old) participated in a within-subject experimental design. Participants performed six breathing conditions within one session, with a 5 min washout period between each condition. Each condition lasted 5 min, with 30 respiratory cycles, and each respiratory cycle lasted 10 s (six cycles per minute), with inhalation/exhalation ratios of 0.8, 1.0, 1.2; and with or without respiratory pauses (0.4 s) between respiratory phases. Results indicated that the root mean square of successive differences (RMSSD), a marker of cardiac vagal activity, was higher when exhalation was longer than inhalation. The presence of a brief (0.4 s) post-inhalation and post-exhalation respiratory pause did not further influence RMSSD. Athletes practicing slow-paced breathing are recommended to use an inhalation/exhalation ratio in which the exhalation phase is longer than the inhalation phase.

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

Slow, deep breathing (SDB) is a common pain self-management technique. Stimulation of the arterial baroreceptors and vagal modulation are suggested, among others, as potential mechanisms underlying the hypoalgesic effects of SDB. We tested whether adding an inspiratory load to SDB, which results in a stronger baroreceptor stimulation and vagal modulation, enhances its hypoalgesic effects. Healthy volunteers performed SDB (controlled at 0.1 Hz) with and without an inspiratory threshold load. Controlled breathing (CB) at a normal frequency (0.23 Hz) was used as an active control. Each condition lasted 90 s, included an electrical pain stimulation on the hand, and was repeated four times in a randomized order. Pain intensity, self-reported emotional responses (arousal, valence, dominance), and cardiovascular parameters (including vagally-mediated heart rate variability) were measured per trial. A cover story was used to limit the potential effect of outcome expectancy. Pain intensity was slightly lower during SDB with load compared with normal-frequency CB, but the effect was negligible (Cohens d < 0.2), and there was no other difference in pain intensity between the conditions. Heart rate variability was higher during SDB with/without load compared with normal-frequency CB. Using load during SDB was associated with higher heart rate variability, but less favorable emotional responses. These findings do not support the role of baroreceptor stimulation or vagal modulation in the hypoalgesic effects of SDB. Other mechanisms, such as attentional modulation, warrant further investigation.

Keeping the Breath in Mind: Respiration, Neural Oscillations, and the Free Energy Principle

Scientific interest in the brain and body interactions has been surging in recent years. One fundamental yet underexplored aspect of brain and body interactions is the link between the respiratory and the nervous systems. In this article, we give an overview of the emerging literature on how respiration modulates neural, cognitive and emotional processes. Moreover, we present a perspective linking respiration to the free-energy principle. We frame volitional modulation of the breath as an active inference mechanism in which sensory evidence is recontextualized to alter interoceptive models. We further propose that respiration-entrained gamma oscillations may reflect the propagation of prediction errors from the sensory level up to cortical regions in order to alter higher level predictions. Accordingly, controlled breathing emerges as an easily accessible tool for emotional, cognitive, and physiological regulation.

Transcutaneous Auricular Vagus Nerve Stimulation Combined With Slow Breathing: Speculations on Potential Applications and Technical Considerations

OBJECTIVES

Transcutaneous auricular vagus nerve stimulation (taVNS) is a relatively novel noninvasive neurostimulation method that is believed to mimic the effects of invasive cervical VNS. It has recently been suggested that the effectiveness of taVNS can be enhanced by combining it with controlled slow breathing. Slow breathing modulates the activity of the vagus nerve and is used in behavioral medicine to decrease psychophysiological arousal. Based on studies that examine the effects of taVNS and slow breathing separately, this article speculates on some of the conditions in which this combination treatment may prove effective. Furthermore, based on findings from studies on the optimization of taVNS and slow breathing, this article provides guidance on how to combine taVNS with slow breathing.

MATERIALS AND METHODS

A nonsystematic review.

RESULTS

Both taVNS and slow breathing are considered promising add-on therapeutic approaches for anxiety and depressive disorders, chronic pain, cardiovascular diseases, and insomnia. Therefore, taVNS combined with slow breathing may produce additive or even synergistic beneficial effects in these conditions. Studies on respiratory-gated taVNS during spontaneous breathing suggest that taVNS should be delivered during expiration. Therefore, this article proposes to use taVNS as a breathing pacer to indicate when and for how long to exhale during slow breathing exercises.

CONCLUSIONS

Combining taVNS with slow breathing seems to be a promising hybrid neurostimulation and behavioral intervention.

"I've learned to look at things in a different way": exploring patients' perspectives on participation in physiotherapist delivered integrated stress inoculation training and exercise for acute whiplash

PURPOSE

To explore patient perspectives of the integrated intervention (intervention arm) of a recent randomised clinical trial that found clinically relevant and sustained benefits of a physiotherapist delivered integrated stress inoculation training (SIT) and exercise for people with acute whiplash-associated disorders (WAD) and at risk of poor recovery.

MATERIAL AND METHODS

Twelve patients from the 53 who participated in the SIT and exercise arm of a randomised controlled trial (StressModex RCT) participated in semi-structured interviews. Data were analysed using inductive thematic analysis.

RESULTS

Five main themes were identified: "balance between the physical and psychological components," "dealing with stress," "coping with the injury," "pain relief and return to function," and "elements enhancing therapeutic alliance."

CONCLUSIONS

The majority of patients found the SIT techniques to be helpful in managing stress and pain, coping with their injury, and returning to function. The patients also found the exercises useful and acknowledged the importance of both the physical and the psychological aspects of whiplash injury.IMPLICATIONS FOR REHABILITATIONPatients with acute WAD at risk of poor recovery welcomed the inclusion of psychological strategies as part of physiotherapy treatment.The patients nominated both the psychological (SIT) component and exercise as assisting them with their stress, pain, and recovery.Physiotherapists could consider including strategies targeting early stress responses in their management of patients with acute WAD.

Psychophysiological responses to various slow, deep breathing techniques

Deep breathing exercises are commonly used for several health conditions including pain and hypertension. Various techniques are available to practice deep breathing, whereas possible differential psychophysiological effects have not been investigated. We compared four deep breathing techniques and examined outcomes in blood pressure variability, respiratory sinus arrhythmia, baroreflex function, and emotional state. Healthy adult volunteers performed pursed-lips breathing, left and right unilateral nostril breathing, and deep breathing with an inspiratory threshold load (loaded breathing), all at a frequency of 0.1 Hz (i.e., controlled breathing) and for three minutes each. Results showed that blood pressure variability was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left and right unilateral nostril breathing. Respiratory sinus arrhythmia was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left unilateral nostril breathing. The effect of breathing condition on respiratory sinus arrhythmia was mediated by alterations in blood pressure variability. There was no difference between the breathing conditions in baroreflex sensitivity or effectiveness. Participants rated pursed-lips breathing as more calming and pleasant and with more sense of control (vs. other conditions). Overall, among the four tested deep breathing techniques, loaded breathing was associated with enhanced cardiovascular effects and pursed-lips breathing with better emotional responses, while also enhancing cardiovascular effects (albeit less than loaded breathing). These findings can be informative in applying deep breathing techniques as self-management interventions for health conditions, in which baroreceptors stimulation and autonomic and emotional modulations can be beneficial, such as pain and hypertension.