SLOW, DEEP BREATHING TO DAMPEN PAIN: EVALUATING THE EFFICACY AND INVESTIGATING THE UNDERLYING PSYCHOPHYSIOLOGICAL MECHANISMS

Pain is the most common symptom for which people seek medical care. Chronic pain is common worldwide, and often not treated adequately, thereby leading to reduced quality of life and high healthcare costs. Recently, there has been increasing attention toward the complexity and biopsychosocial nature of pain, and the need for multidisciplinary pain management has been increasingly acknowledged. Various mind-body interventions are being used for pain management, and some of them have been found to be effective. Slow, deep breathing is a commonly applied mind-body intervention for the management of pain. Some of the previous experimental studies found an influence of slow, deep breathing on pain outcomes. However, the results have not been consistent across studies and the underlying mechanisms are largely unknown. Some of the proposed mechanisms are emotional and cognitive modulation of pain perception and stimulation of the arterial baroreceptors and pulmonary vagal afferents. The aim of this Ph.D. project was to evaluate the effect of slow, deep breathing on pain perception in healthy subjects and to investigate the underlying psychophysiological mechanisms. To further investigate the arterial baroreceptors and pulmonary vagal afferents as possible mechanisms for the hypoalgesic effects of slow, deep breathing, we first determined whether adding an inspiratory threshold load to slow, deep breathing can enhance its effects on the cardiovascular responses (Chapter 3). We found an increase in the amplitude of blood pressure variation accompanied by an increase in respiratory sinus arrhythmia in response to increasing loads, suggesting that applying inspiratory threshold loads during slow, deep breathing results in stronger stimulation of the arterial baroreceptors. In a complementary study (Chapter 4) we compared four slow, deep breathing techniques (loaded slow, deep breathing, left and right unilateral nostril breathing, and pursed-lips breathing) with regards to psychophysiological responses. We found that loaded slow, deep breathing and pursed-lips breathing techniques are associated with a larger amplitude of blood pressure variation and respiratory sinus arrhythmia, suggesting stronger stimulation of the arterial baroreceptors with these techniques. Moreover, the pursed-lips breathing technique was associated with lower emotional arousal and more pleasantness and a sense of control. Based on these two studies, we investigated the effect of loaded slow, deep breathing and pursed-lips breathing on somatic pain perception (Chapter 5). We found that loaded slow, deep breathing, but not pursed-lips breathing, reduces pain intensity compared with a control condition. However, physiological responses to loaded slow, deep breathing did not mediate its effect on pain perception. Finally, we evaluated the effect of slow, deep breathing on visceral pain perception. We found that slow, deep breathing reduces visceral pain intensity compared with uncontrolled breathing, but the effect is similar to controlled breathing at normal breathing frequency. Physiological and emotional responses to slow, deep breathing did not mediate its effects on visceral pain perception. The studies in this PhD project helped us to better test and understand the role of different psychophysiological mechanisms in somatic and visceral pain modulation by slow, deep breathing. Overall, our studies do not support the role of baroreceptors and vagal afferents stimulation as possible mechanisms mediating the effect of slow, deep breathing on pain perception, suggesting other potential mechanisms, notably attentional modulation may be at play. Further experimental studies are required to better investigate the role of attentional and emotional modulation on pain inhibition by breathing exercises. Also, clinical studies are required to test whether breathing exercises can modulate pain perception in various patient populations and if so, the underlying mechanisms will need elucidation.

Jaar van publicatie:2020

Toegankelijkheid:Open