Associations between attention, affect and cardiac activity in a single yoga session for female cancer survivors: An enactive neurophenomenology-based approach
Introduction
Contemporary yoga practice consists of lifestyle prescriptions, postures, breath regulation, and meditative techniques, all of which can be modified depending on the desired outcomes and health status of the practitioner (Bower, Woolery, Sternleib, & Garet, 2005). Emerging research suggests yoga not only shares many of the benefits of exercise but also adds yoga-specific psychophysiological regulation of attention, respiration, relaxation, and autonomic nervous system function (Evans et al., 2009, Khalsa, 2004). Studies comparing yoga and exercise indicate that, in healthy individuals and those with various health conditions, yoga can be as effective as more contemporary Western forms of exercise including walking, jogging, cycling, and aerobics at improving a variety of health-related outcome measures, including quality of life, mood, stress, and fatigue (Ross & Thomas, 2010). Within cancer treatment settings, yoga practitioners compared to controls show greater improvements in overall health-related quality of life, psychological health, stress-related symptoms, fatigue, and sleep indices (Boehm et al., 2012, Cramer et al., 2012a, Cramer et al., 2012b, Culos-Reed et al., 2012, Lin et al., 2011, Smith and Pukall, 2009), though reported improvements have not been uniform (Zhang, Yang, Tian, & Wang, 2012).
Yoga practices are said to have numerous applications, ranging from spiritual liberation or Kaivalya, as per the Yoga Sutras of Patañjali (YS IV.34) (Bryant, 2009), to ordinary physical and mental training (Rao, 2011). However, the root aim of yoga can be summarized in Patañjali’s definition of Yoga as a path towards “stilling the changing states of the mind” – Chitta vritti nirodaha (YS I.2) (Bryant, 2009). Briefly, the term chitta in Indian yogic philosophy is used to denote the mind or consciousness in its entirety and associated functions. Chitta can be considered, “the seat of one’s cognition, volition, feelings and actions” (Rao, 2005, p. 13). Vritti refers to any permutation or activity of this mind or consciousness. According to Patañjali, these mental states are in a constant state of fluctuation or change (Rao, 1998). Nirodaha refers to the complete control or stilling of these mental activities so that one experiences the mind or consciousness unrestricted by this constant state of mental vacillation (Rao, 2012). Control of these changing mental states comes from persevering practice aimed at both attaining and maintaining states of mental stability and equanimity over long, uninterrupted periods of time (YS I.12-I.14) (Bryant, 2009). Importantly, meditative states subjectively experienced during yoga practice are related to neurophysiological systems that mediate both focus of attention and affect regulation (Rubia, 2009, Telles and Raghavendra, 2011).
These meditative states can be further divided into two broad categories (Lutz, Slagter, Dunne, & Davidson, 2008): (1) focused attention meditation, which entails voluntary sustained attention on a meditation object of choice, whether external or visualized images, words or sounds, or physical sensations, including the breath; and (2) open monitoring meditation, which involves monitoring the content of present-moment experience without focus on an explicit object per se. Both meditative states have correlates in the Yoga Sutras of Patañjali, in which they are referred to as dharana, which requires focused attention, and dhyana, open monitoring in which an expansive mental state is reached (Telles & Raghavendra, 2011). Of importance to both forms of meditation is the maintenance of an optimum level of arousal or activation (Lutz, 2007). One seeks to avoid the two extremes of dullness or tiredness on the one hand, and excitement or tension on the other. The mind is initially calmed and distractions are reduced via focused attention. From this calm and focused state the practitioner develops a foundation to enter into open monitoring, in which the focus shifts from the meditative object to present-moment experience (Lutz et al., 2008, Slagter et al., 2011, Telles and Raghavendra, 2011). It is thought consistent practice of these skills lead to a trait-like change in which the regulative skills of focused attention are applied less and less frequently, open monitoring meditative states become predominant, and mental calmness and focus become progressively more effortless (Slagter et al., 2011).
The purpose of the current project was to utilize a neurophenomenology-based approach to investigate associations between attention, affect, and cardiac activity in a single yoga session in a group of female yoga practitioners who had survived a cancer experience. The present study also used several supplementary psychological theories to frame the posited attentional, affective, and psychophysiological responses to yoga practice. Theories include: the Effort-Related Attention Model, the Circumplex Model of Affect, the Dual-Mode Theory of Affective Responses to Exercise, and the Neurovisceral Integration Model.
Neurophenomenology is a mixed-methods research approach used to investigate conscious experience (Lutz and Thompson, 2003, Thompson, 2006, Varela, 1996). The neurophenomenological approach provides mutually informative insights between subjective first-person experience, second-person dialogical enquiry stemming from interactions between research participants and the investigator, and third-person neuroscientific data. Neurophenomenology has been used previously to examine contemplative practices, particularly among advanced meditation practitioners using primarily electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) to directly measure brain activity (Farb et al., 2007, Lutz et al., 2008, Lutz et al., 2004, Lutz et al., 2002, Lutz et al., 2009). Emerging research has called for an integration of neurophenomenology, cognitive and affective neuroscience, and psychophysiology – an “affective neuro-physio-phenomenology” (Colombetti, 2013) – to investigate the neurophysiological underpinnings of different attentional and affective states and their relationship to consciousness. This “enactive” approach directs neurophenomenology towards understanding the relationship between subjective experience and the entire psychophysiological organism (Colombetti and Thompson, 2008, Thompson, 2005).
To investigate how yoga practice regulates attention, we explored research in the area of exercise science to further frame our study. Briefly, focus of attention during exercise can influence changes in affective responses (Lind, Welch, & Ekkekakis, 2009). Attention within exercise settings can be defined as associative, or focusing on present-moment physical sensations related to exercise, while dissociative attention can be defined as focusing on non-exercise-related stimuli and diverting attention away from internal sensations and present exercise experience (LaCaille, Masters, & Heath, 2004). In accordance with the Effort-Related Attention Model (Tenenbaum, 2001), associative and dissociative attention strategies during exercise vary depending on exercise intensity. During exercise at low-to-moderate workloads, attention can be controlled voluntarily and switch between dissociative and associative modes. However, at higher exercise intensities, the intensification of physiological cues forces an involuntary shift in attention to aversive interoceptive stimuli (Tenenbaum & Connolly, 2008).
In relation to focus of attention, yoga practice provides an opportunity for sustained attention to physical sensations, breathing, and the contents of the mind through progressive sequences of varying intensity, including dynamic movements, restful postures, breathing exercises, and periods of meditative awareness. The strong mind–body interaction within contemporary yoga practice adds a unique contemplative dimension to exercise that has been referred to as ‘mindfulness in motion’ (Salmon, Lush, Jablonski, & Sephton, 2009). Mindfulness is defined as the ability to direct attention towards events in the field of consciousness (thoughts, emotions, physical sensations) in the present moment without judgment (Brown & Cordon, 2009). Within exercise settings, mindfulness builds upon associative attention by refining perceptions of exertion on a moment-by-moment basis via increased sensitivity to a host of cognitive and interoceptive cues, and concurrently limits emotional reactivity to these cues (Salmon, Hanneman, & Harwood, 2010).
To explore affective responses to yoga practice we utilized the Circumplex Model of Affect (Posner, Russell, & Peterson, 2005), which suggests affect can be represented by two orthogonal and bipolar dimensions: valence (pleasure versus displeasure), and perceived activation or arousal (high versus low). These two dimensions of valence and activation jointly define the content domain of core affect, and are theorized to underlie all affective states. Combinations of these two dimensions are described as: high activation pleasure (e.g., energy), low activation pleasure (e.g., calmness), high activation displeasure (e.g., tension), and low activation displeasure (e.g., tiredness) (Yik, Russell, & Barrett, 1999) (see Fig. 1.1). Unlike approaches based on sampling only a few distinct states (e.g., specific mood states), the Circumplex Model captures the most phenomenologically salient features of the affective response to any given stimulus by tapping its constituent dimensions (Ekkekakis, 2013).
Dual Mode Theory (Ekkekakis, 2003) proposes affective responses related to exercise are regulated via the continuous interplay of both cognitive processes and interoceptive cues. The relative importance of these two factors in the regulation of core affect is hypothesized to shift systematically as a function of exercise intensity. Exercise performed at intensities above lactate or ventilatory thresholds leads to negative affective experiences of exercise when workload increases to a point that exercise cannot be physiologically maintained and interoceptive cues indicate one should stop. Exercising below this threshold leads to positive affective experiences, as individuals are able to maintain this workload, which bolsters positive cognitive factors (Ekkekakis, Parfitt, & Petruzzello, 2011). In relation to yoga practice, participation in a single yoga session has been associated with significant improvements in positive affect and reductions in negative affect comparable to changes seen with moderate intensity aerobic exercise (Netz and Lidor, 2003, West et al., 2004).
Heart rate variability (HRV) represents the complex beat-to-beat variation in heart rate produced by the interplay of sympathetic and parasympathetic autonomic neural activity as recorded via an electrocardiogram (ECG) (Task Force of the European Society of Cardiology & Electrophysiology, 1996). In general, higher parasympathetic (vagal) mediation of HRV is associated with positive health outcomes (Rajendra Acharya et al., 2006, Thayer and Ruiz-Padial, 2006). The Neurovisceral Integration Model (Thayer & Lane, 2009) implicates a common reciprocal neural network between the heart and brain. This network, which can be indexed with HRV, serves as the structural link between psychological processes like emotion and cognition, and health-related physiological processes. Those with lower resting HRV (indicative of decreased parasympathetic and/or increased sympathetic nervous system activity) are at risk for both psychological and physiological dysfunction, whereas both exercise training and a higher level of aerobic fitness are associated with greater parasympathetic modulation of cardiac autonomic function (Routledge, Campbell, McFetridge-Durdle, & Bacon, 2010).
Yoga programs are reported to result in increased parasympathetic nervous system (PNS) activity (Khattab et al., 2007, Telles et al., 2013). Streeter, Gerbarg, Saper, Ciraulo, and Brown (2012) hypothesize yoga practice corrects PNS under-activity via stimulation of the vagus nerves to ameliorate stress-related illness symptoms. During active yoga poses, heart rate and respiration increases in a manner consistent with exercise (Cowen & Adams, 2007). However, during and following the restful supine and seated meditative postures that conclude most yoga classes, parasympathetic activity is consistent with relaxation and reduced physiological arousal (Sarang & Telles, 2006).
Given these connections between yoga, attention, affect, and cardiac activity, our investigation required the addition of HRV as a novel correlate of psychophysiological function. In addition, both the Effort-Related Attention Model and Dual Mode Theory suggest attentional and affective experience during exercise is driven by the physiological intensity of exercise itself. While common physiological indices of exercise intensity are ventilatory and/or lactate thresholds (McArdle, Katch, & Katch, 2009), yoga practice is generally considered low-intensity and occurs below these ventilatory or lactate thresholds (Ray, Pathak, & Tomer, 2011). Given these associations, measurement of cardiac activity throughout each yoga session provided appropriate neurophysiological indices sensitive to lower-intensity yoga practice-related changes.
Taking Patañjali’s definition that yoga is the “stilling of the changing states of the mind” (YS I.2) (Bryant, 2009) as a guide, the purpose of the present study was to investigate participants’ experience of a single yoga session in an effort to understand how yoga practice influences immediate attentional and affective experience. The aims of the current study were threefold: to investigate (1) whether yoga practice elicits (a) increased attention and positive affective valence, and (b) activation, perceived exertion, and cardiac activity consistent with the intensity of each yoga sequence during a single yoga session; (2) associations between these variables across measurement occasions; and (3) whether participants’ subjective first-person descriptions of their experience of the yoga session corroborated quantitative findings.
Section snippets
Procedures
Ethical approval was obtained from the Conjoint Health Research Ethics Board (CHREB) of the University of Calgary/Alberta Health Services and all participants completed a CHREB-approved informed consent prior to study enrollment. The study sample was drawn from participants who had previously completed Yoga Thrive, a research-based 7-week therapeutic yoga program for cancer survivors and their support persons, as described previously (Mackenzie, Carlson, Ekkekakis, Paskevich, & Culos-Reed, 2013
Demographics
The mean participant age was 54.0 years. All participants were Caucasian and female, and 61.1% of participants had received a breast cancer diagnosis, stage II-III, approximately 36.0 months prior to study enrollment. Participants were commonly married (55.6%), highly educated (61.1%), affluent (44.4%) and many participants had returned to work full-time (61.1%). Participants had completed a 7-week yoga for cancer survivors program a mean of 4.9 times previously. The average participant BMI was
Attention, affective valence, activation, and perceived exertion
The impetus for the present study was to investigate yoga’s ability to “still the changing states of the mind” in a single yoga session. This is the first study to integrate models of attention and affect within an overarching neurophenomenology-based framework, using several supplementary theories to frame the posited attentional, affective, and psychophysiological responses to yoga practice, and accompanying methodologies (patient reported outcomes, cardiac activity indices, and first-person
Conclusion
The current research was designed to model neurophenomenological processes and outcomes while taking into consideration a traditional definition of yoga as “stilling of the changing states of the mind (YS I.2).” The result is an initial detailed exploration of the attentional and affective experience of yoga practice. The intention was to bridge the “explanatory gap” (Lutz & Thompson, 2003) between the phenomenal character of yoga practice with the quantitative measurement of the yoga
Conflict of Interest
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Acknowledgments
The authors would like to thank all the study participants and yoga teachers involved in this research. We thank Gisela Engels (University of Calgary) for her statistical support, Laura Labelle, PhD (Tom Baker Cancer Centre) and Sheila Garland, PhD (Perelman School of Medicine) for their editorial contributions to this manuscript, and Brandon Hisey, MSc (University of Calgary) for his assistance in developing the Three-Dimensional Circumplex Model. We would also like to thank the two anonymous
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