Steffen Patrick R, Bartlett Derek, Channell Rachel Marie, Jackman Katelyn, Cressman Mikel, Bills John, Pescatello Meredith
Department of Psychology, Brigham Young University, Provo, UT, United States.
Front Psychol. 2021 Feb 15;12:624254. doi: 10.3389/fpsyg.2021.624254. eCollection 2021.
Approaches to improve heart rate variability and reduce stress such as breathing retraining are more frequently being integrated into psychotherapy but little research on their effectiveness has been done to date. Specifically, no studies to date have directly compared using a breathing pacer at 6 breaths per minute with compassion focused soothing rhythm breathing.
In this randomized controlled experiment, 6 breaths per minute breathing using a pacer was compared with compassion focused soothing rhythm breathing, with a nature video being used as a control group condition.
Heart rate variability (HRV) measures were assessed via electrocardiogram (ECG) and respiration belt, and an automated blood pressure machine was used to measure systolic diastolic blood pressure, and heart rate (HR). A total of 96 participants were randomized into the three conditions. Following a 5-min baseline, participants engaged in either 6 breath per minute breathing, soothing rhythm breathing, or watched a nature video for 10 min. To induce a stressful state, participants then wrote for 5 min about a time they felt intensely self-critical. Participants then wrote for 5 min about a time they felt self-compassionate, and the experiment ended with a 10-min recovery period.
Conditions did not significantly differ at baseline. Overall, HRV, as measured by standard deviation of NN intervals (SDNN), low frequency HRV (LF HRV), and LF/HF ratio, increased during the intervention period, decreased during self-critical writing, and then returned to baseline levels during the recovery period. High frequency HRV (HF HRV) was not impacted by any of the interventions. The participants in the 6 breath per minute pacer condition were unable to consistently breathe at that rate and averaged about 12 breaths per minute. Time by Condition analyses revealed that both the 6 breaths per minute pacer and soothing breathing rhythm conditions lead to significantly higher SDNN than the nature video condition during breathing practice but there were no significant differences between conditions in response to the self-critical and self-compassionate writing or recovery periods. The 6 breath per minute pacer condition demonstrated a higher LF HRV and LF/HF ratio than the soothing rhythm breathing condition, and both intervention conditions had a higher LF HRV and LF/HF ratio than the nature video.
Although the 6 breath per minute pacer condition participants were not able to breath consistently at the low pace, both the participants attempting to breathe at 6 breaths per minute as well as those in the soothing rhythm breathing condition effectively increased HR variability as measured by SDNN, and attempting to breathe at 6 breaths per minute led to the highest LF HRV and LF/HF ratio. Both breathing approaches impacted HRV more than watching a relaxing nature video and can potentially be used as key adjuncts in psychotherapy to aid in regulating physiological functioning, although it appears that consistent breathing practice would be needed.
诸如呼吸再训练等改善心率变异性和减轻压力的方法越来越多地被纳入心理治疗中，但迄今为止对其有效性的研究很少。具体而言，迄今为止尚无研究直接比较使用每分钟6次呼吸的呼吸起搏器与以同情为重点的舒缓节奏呼吸。
在这项随机对照实验中，将使用起搏器进行的每分钟6次呼吸与以同情为重点的舒缓节奏呼吸进行了比较，并将自然视频用作对照组条件。
通过心电图（ECG）和呼吸带评估心率变异性（HRV）指标，并使用自动血压计测量收缩压、舒张压和心率（HR）。总共96名参与者被随机分为三种条件。在5分钟的基线期后，参与者进行每分钟6次呼吸、舒缓节奏呼吸，或观看10分钟自然视频。为了诱导压力状态，参与者随后花5分钟写下他们感到强烈自我批评的时刻。然后，参与者花5分钟写下他们感到自我同情的时刻，实验以10分钟的恢复期结束。
各条件在基线期无显著差异。总体而言，通过NN间期标准差（SDNN）、低频HRV（LF HRV）和LF/HF比值测量的HRV在干预期增加，在自我批评写作期间减少，然后在恢复期恢复到基线水平。高频HRV（HF HRV）不受任何干预影响。每分钟6次呼吸起搏器条件下的参与者无法始终以该速率呼吸，平均每分钟约12次呼吸。时间×条件分析显示，在呼吸练习期间，每分钟6次呼吸起搏器和舒缓呼吸节奏条件下的SDNN均显著高于自然视频条件，但在对自我批评和自我同情写作或恢复期的反应中，各条件之间无显著差异。每分钟6次呼吸起搏器条件下的LF HRV和LF/HF比值高于舒缓节奏呼吸条件，且两种干预条件下的LF HRV和LF/HF比值均高于自然视频。
尽管每分钟6次呼吸起搏器条件下的参与者无法始终以低速率呼吸，但试图以每分钟6次呼吸以及处于舒缓节奏呼吸条件下的参与者，通过SDNN测量均有效地增加了HR变异性，并且试图以每分钟6次呼吸导致了最高的LF HRV和LF/HF比值。两种呼吸方法对HRV的影响均大于观看放松的自然视频，并且有可能在心理治疗中用作关键辅助手段以帮助调节生理功能，尽管似乎需要持续的呼吸练习。
