Limitations, methodological considerations and future research
depression, sleep disturbance, anxiety, inflammatory bowel disease
REGRESSION, INFLAMMATORY BOWEL DISEASE
Null effects may be accounted for by a number of factors. First, the intervention may have offered an inadequate dose of CB. Practices may have been too brief (in minutes), the intervention too short (in weeks), and the breathwork inadequately calibrated or insufficiently contextualised in this fully remote intervention design. Participants were offered a single, recorded ~ 10 min CB practice for daily engagement over four weeks. Self-reported engagement indicated 20 sessions per participant on average, although previous work has suggested a significant optimistic bias in reporting engagement with brief digital interventionsSecond, it may be the case that this would be an adequate dose of CB if what was practised was well-calibrated to the method. Remote non-personalised delivery meant that there was no real-time feedback, visual or otherwise, to ensure participants were performing CB in an ideal manner (i.e., abdominally/diaphragmatically, pacing breathing correctly and/or not pausing for breath). In addition, to ensure methodological rigour and successful blinding, there was no psychoeducation nor context provided for why participants were breathing at the rate of ~ 5.5 bcpm. The standardisation and unsupported nature of this online CB—without expectation-loaded language related to the exact breathing rate used and desired subjective experiences—meant that such neutrality could have diluted intention and meaning of the technique itself. In most contemplative practices including mindfulness, meditation, yoga, and pranayama (breathwork), context and learning are regularly provided before teaching a specific technique. Psychoeducation paired with breathwork could thus complement practices and lead to improved, prolonged outcomes. In summary, the full potential of CB was not adequately realised by following this standalone recorded guidance. However, such reduction in standardisation of protocols could introduce numerous confounding variables, such as effects pertaining to artificially enhancing expectation of benefit, cognition, the breathwork facilitator and individualised guidance, making findings difficult to interpret. This also decreases accessibility compared to entirely remote, self-help delivery and reduces the feasibility of recruiting a large general population sample as we successfully did here.Third, it is possible that in creating a 12 bcpm paced, abdominal/diaphragmatic, nasal breathwork of this kind we have inadvertently developed an active intervention of equivalent potency to CB at this small dose. Indeed, in addition to the lack of difference on the credibility and expectancy measures, there was similar overall positive sentiment between arms in qualitative feedback. Thus, our findings could reflect the effects of two active intervention arms rather than one intervention versus a placebo. Whilst intended to reflect a spontaneous breathing rate it is possible that paced breathing alone (as opposed to un-paced) has some beneficial effects. Perhaps simply ‘conscious breathing’ that invites attention to the breath, and regulates breathing pace, without significantly slowing it can improve stress. It is also likely that the placebo breathing pace was in the lower range of average resting respiration rate for most participants, and therefore could be considered a ‘slower’ breathwork, in turn masking the effects of CB in our study. There is little available evidence that paced breathing in the range of 12 bcpm is associated with significant benefits of this kind. However, one study with 53 healthy participants found a rise in vagal activity and shift towards parasympathetic nervous system balance (i.e., the ‘rest and digest’ response) when breathing at a rate of 8 bcpm and 12 bcpm compared to 16 bcpm, though results yielded for 8 bcpm were more pronounced and significant overallPace aside, in our study it is possible that the paced breathing guidance in both groups led to beneficial deeper breathing, and abdominal/diaphragmatic breathing alone could be responsible for the change in outcomes in both conditions. Participants in both groups were instructed to breathe abdominally/diaphragmatically and through the nose, a method which has been shown to be associated with decreases in DASS stress, anxiety and depression in another study where participants practised just ~ 5/min daily diaphragmatic breathing exercises (inhale through nose and controlled exhale through mouth at an unspecified rate) followed by ~ 5 min of rest, over one month, compared to standard careAlternatively, nasal breathing was also invited in all participants and could also be responsible for change in both conditions. In comparison to mouth breathing, nasal breathing can result in 10–20% greater oxygen intakeSo, it is possible that our placebo conferred specific, unanticipated benefits to participants in this study through paced, abdominal/diaphragmatic and nasal breathing instructions, masking a real benefit of CB. However, it is, at least, equally plausible that the changes over time seen in both conditions may be explained by effects of expectation, attention, history, maturation or regression to the meanAnother possibility is that beneficial effects of CB were missed by our methods. Perhaps CB is effective but not in the sample recruited to our study using the Prolific platform who may not be representative of the general population (cf. Peer et al.Alternatively, it is possible that CBs distinct effects are more physiological than psychological, and registered in short-term cardiovascular changes rather than a shift in felt sense of stress resilience. For example, a study with inflammatory bowel disease patients showed significant psychological improvements along with reductions in C-reactive protein (a biomarker for inflammation)It is also possible that in the case of a ‘low dose’ CB intervention of this kind, the effects may be momentary but not long-lasting. Previous work has reported beneficial effects on state mood and state anxiety, but not perceived stress, trait anxiety, depression or sleep disturbance associated with brief/remote breathworkThe question remains whether regular breathwork practise at a specific dose can extend beneficial transient effects to enduring change or allow people to access these emotional state shifts more readily and quickly. Thus, trait outcomes are still important as, akin to physical exercise, the accumulation of state benefits could lead to such durable change and improved ability to access shifts in state. While mechanisms of action for breathwork, or at least brief practices, may therefore possibly be more physiological and short-lasting (state) versus cognitive and potentially longer-term (trait), greater practise (dose) could mean practitioners can access such shifts in emotional state when desirable/needed, i.e., wanting to feel calm in real-time and thus incorporating ‘situational breathwork’ in the moment.