Sudarshan Kriya Yoga improves cardiac autonomic control in patients with anxiety-depression disorders

Highlights

• SKY training improves the cardiac autonomic control and cardiorespiratory coupling.

• All patients were stable and under the same therapy for at least 6 months.

• The homogeneity of the study population, which is free of any comorbidities.

Abstract

Background

Several studies have demonstrated that adjuvant therapies as exercise and breathing training are effective in improving cardiac autonomic control (CAC) in patients with affective spectrum disorders. However, the effects of Sudarshan Kriya Yoga (SKY) on autonomic function in this population is unknown. Our objective was to test the hypothesis that SKY training improves CAC and cardiorespiratory coupling in patients with anxiety and/or depression disorders.

Methods

Forty-six patients with a diagnosis of anxiety and/or depression disorders (DSM-IV) were consecutively enrolled and divided in two groups: 1) conventional therapy (Control) and 2) conventional therapy associated with SKY (Treatment) for 15 days. Anxiety and depression levels were determined using quantitative questionnaires. For the assessment of CAC and cardiorespiratory coupling, cardiorespiratory traces were analyzed using monovariate and bivariate autoregressive spectral analysis, respectively.

Results

After 15-days, we observed a reduction of anxiety and depression levels only in Treatment group. Moreover, sympathetic modulation and CAC were significantly lower while parasympathetic modulation and cardiorespiratory coupling were significantly higher in the Treatment compared to Control group.

Conclusions

Intensive breathing training using SKY approach improves anxiety and/or depressive disorders as well as CAC and cardiorespiratory coupling. These finding suggest that the SKY training may be a useful non-pharmacological intervention to improve symptoms and reduce cardiovascular risk in patients with anxiety/depression disorders.

Introduction

Besides being common lifelong, affective spectrum disorders are some of the most burdensome diseases with respect to their global impact on morbidity, mortality, and loss of quality of life (Baxter et al., 2013, De Wilde et al., 2007, Pavlova et al., 2015, Waraich et al., 2004). While many mechanisms have been proposed, attention to autonomic dysfunction remains of interest for several researches (Taylor, 2010, Voss et al., 2011). The polyvagal theory has emerged as an important explanatory construct for a wide range of psychiatric conditions and provides a new perspective by emphasizing the phylogeny of the autonomic nervous system (Porges, 2007, Porges, 2009). According to this theory, the myelinated vagal fibers originating in the nucleus ambiguous may mediate the relationship between autonomic dysfunction and altered social behavior in patients with mood disorders (Beauchaine et al., 2007).

From this point of view, the cardiorespiratory coupling is an important physiological mechanism and has been largely associated with cardiac vagal modulation (Bar et al., 2008, Peupelmann et al., 2009). Beside the mechanical interaction due to the coupling between the systemic and pulmonary circulations during breathing, cardiac and respiratory systems are closely linked by neuronal pathways through overlapping brainstem networks that modulate the autonomic nervous system and are essential for survival (Dick et al., 2014). During inspiration the pulmonary stretch receptors are stimulated and this information is transmitted via pulmonary C-fiber afferents to medullary nuclei of central integration that reflexively inhibit the cardiac vagal efferent activity causing the shortening of the R-R interval (RRi). In contrast, during expiration this signaling is abolished and the activity of the efferent cardiac vagal nerve is stimulated due to central integration between cardioinhibitory reflexes (i.e. arterial baroreflex) causing the extending the RRi (Dick et al., 2014, Yasuma and Hayano, 2004).

It has been documented that elevated levels of anxiety alters the parameters of the breathing pattern, eliciting increased respiratory rate and tidal volume and decreased respiratory time in healthy individuals (Mador and Tobin, 1991, Masaoka and Homma, 1997). In addition, due to the high prevalence of metabolic abnormalities such as obesity, diabetes and dyslipidemia (Teixeira and Rocha, 2007; Vancampfort et al., 2015), patients with mood disorders have autonomic dysfunction and reduced cardiorespiratory coupling (Bar et al., 2010, Berger et al., 2011, Voss et al., 2011) which increases the risk of cardiovascular disease.

On the other hand, several studies have demonstrated that adjuvant therapies such as physical exercise and breathing training are effective in improving cardiac autonomic control (CAC) in patients with affective spectrum disorders (Booij et al., 2015, Brown and Gerbarg, 2005). Based on Yoga techniques, it has been consistently shown that breathing exercises have beneficial effects on CAC and breathing function (Santaella et al., 2011), enhance cardiorespiratory adaptation to hypoxia (Bernardi et al., 2007) and improve mood state (Pascoe and Bauer, 2015).

Sudarshan Kriya Yoga (SKY) is a comprehensive program based on some yoga techniques that includes bodily postures, powerful breathing exercises and meditation (Janakiramaiah et al., 1998). Briefly, the what particularly differentiate SKY form other Yoga-based interventions is a set of three sequencial breathing technique, Ujjiay – slow and forced breathing, 3 cycles per minute; Bhastrika – rapid exalation at 20–30 cycles per minute; Sudarshan Kriya – rhythmic, cyclical breathing of slow, medium, fast cycles (Brown and Gerbarg, 2005). Besides being an approach safe and low-cost, several evidences support which SKY can be a beneficial adjunct to the treatment of stress, anxiety and depression (Brown and Gerbarg, 2005, Doria et al., 2015). However, the effects of SKY on autonomic function in patients with anxiety and/or depression disorders is unknown. To answer this question, the objective of this research was to evaluate the effects of intensive breathing by SKY training on CAC and cardiorespiratory coupling.