Attention to internal body sensations is practiced in most meditation traditions. Many traditions state that this practice results in increased awareness of internal body sensations, but scientific studies evaluating this claim are lacking. We predicted that experienced meditators would display performance superior to that of nonmeditators on heartbeat detection, a standard noninvasive measure of resting interoceptive awareness. We compared two groups of meditators (Tibetan Buddhist and Kundalini) to an age- and body mass index-matched group of nonmeditators. Contrary (...) to our prediction, we found no evidence that meditators were superior to nonmeditators in the heartbeat detection task, across several sessions and respiratory modulation conditions. Compared to nonmeditators, however, meditators consistently rated their interoceptive performance as superior and the difficulty of the task as easier. These results provide evidence against the notion that practicing attention to internal body sensations, a core feature of meditation, enhances the ability to sense the heartbeat at rest. (shrink)

Attention to internal body sensations is practiced in most meditation traditions. Many traditions state that this practice results in increased awareness of internal body sensations, but scientific studies evaluating this claim are lacking. We predicted that experienced meditators would display performance superior to that of nonmeditators on heartbeat detection, a standard noninvasive measure of resting interoceptive awareness. We compared two groups of meditators (Tibetan Buddhist and Kundalini) to an age- and body mass index-matched group of nonmeditators. Contrary (...) to our prediction, we found no evidence that meditators were superior to nonmeditators in the heartbeat detection task, across several sessions and respiratory modulation conditions. Compared to nonmeditators, however, meditators consistently rated their interoceptive performance as superior and the difficulty of the task as easier. These results provide evidence against the notion that practicing attention to internal body sensations, a core feature of meditation, enhances the ability to sense the heartbeat at rest. (shrink)

The perception of being located within one’s body is an essential feature of everyday self-experience. However, by manipulating exteroceptive input, healthy participants can easily be induced to perceive themselves as being spatially dislocated from their physical bodies. It has previously been suggested that interoception, i.e., the processing of inner physiological signals, contributes to the stability of body representations; however, this relationship has not previously been tested for different dimensions of interoception and bodily self-location. In the present study, using an advanced (...) automatized setup, we systematically manipulated participants’ perspective of their own body as well as the synchrony of visuotactile stimulation. The malleability of bodily self-location was assessed using a questionnaire targeting in-body and out-of-body experiences. Participants also performed a heartbeat discrimination task to assess their interoceptive accuracy, interoceptive sensibility, and interoceptive awareness. Bodily self-location was significantly influenced by perspective, with third-person perspective being associated with stronger out-of-body experiences compared to first-person perspective. Furthermore, there was a significant perspective × stimulation interaction, with subsequent analyses showing that participants reported out-of-body experiences particularly under third-person perspective combined with synchronous visuotactile stimulation. Correlation and regression analyses revealed that meta-cognitive interoceptive awareness was specifically and negatively related to the exteroceptively mediated malleability of body experiences. These results indicate that the perception of the self being located within one’s body relies on the interaction of exteroceptive input and higher-order interoceptive abilities. This has implications for theoretical considerations about the bodily self in health as well as for the understanding of disturbed bodily self-processing in clinical contexts. (shrink)

Research has shown repeatedly that attention influences implicit learning effects. In a similar vein, interoceptive awareness might be involved in unaware fear conditioning: The fact that the CS is repeatedly presented in the context of aversive bodily experiences might facilitate the development of conditioned responding. We investigated the role of interoceptive attention in a subliminal conditioning paradigm. Conditioning was embedded in a spatial cueing task with subliminally presented cues that were followed by a masking stimulus. Response times (...) to the targets that were either validly or invalidly predicted by the cues served as index of conditioning. Interoceptive attention was manipulated between-subjects. Half the participants completed a heartbeat detection task before conditioning. This task tunes attention to one’s own bodily signals. We found that conditioned responding was facilitated in this latter group of participants. These results are in line with the hypothesis that a rise interoceptive attention enhances unaware conditioned responding. (shrink)

Psychology distinguishes between a bodily and a narrative self. Within neuroscience, models of the bodily self are based on exteroceptive sensorimotor processes or on the integration of interoceptive sensations. Recent research has revealed interactions between interoceptive and exteroceptive processing of self-related information, for example that mirror self-observation can improve interoceptive awareness. Using heartbeat perception, we measured the effect on interoceptive awareness of two experimental manipulations, designed to heighten attention to bodily and narrative aspects of (...) the self. Participants gazed at a photograph of their own face or at self-relevant words. In both experimental conditions interoceptive awareness was significantly increased, compared to baseline. Results show that attention to narrative aspects of self, previously regarded as relying on higher-order processes, has an effect similar to self-face stimuli in improving interoceptive awareness. Our findings extend the previously observed interaction between the bodily self and interoception to more abstract amodal representations of the self. (shrink)

Body awareness refers to the individual ability to process signals originating from within the body, which provide a mapping of the body’s internal landscape and its relation with space and movement. The present study aims to evaluate psychometric properties and validate in French two self-report measures of body awareness: the Postural Awareness Scale, and the last version of the Multidimensional Assessment of Interoceptive Awareness questionnaire. We collected data in a non-clinical, adult sample using online survey, (...) and a subset of the original sample also completed the retest control. Factor analyses and reliability analyses were conducted. Construct validity of the PAS and the MAIA-2 were examined by testing their association with each other, and with self-report measures of personality, alexithymia and dispositional trait mindfulness. Factor analyses of the PAS supported the same two-factor structure as previously published versions. For the MAIA-2, factor analyses suggested that a six-factor structure, excluding Not-Worrying and Not-Distracting factors, could successfully account for a common general factor of self-reported interoception. We found satisfactory internal consistency, construct validity, and reliability over time for both the PAS and the MAIA-2. Altogether, our findings suggest that the French version of the PAS and the MAIA-2 are reliable self-report tools to assess both components of body awareness. (shrink)

The capacity to perceive internal bodily states is linked to emotional awareness and effective emotional regulation. We explore individual differences in emotional awareness in relation to the fading affect bias, which refers to the greater dwindling of unpleasant compared to pleasant emotions in autobiographical memory. We consider interoceptive awareness and alexithymia in relation to the FAB, and private event rehearsal as a mediating process. With increasing interoceptive awareness, there was an enhanced FAB, but with (...) increasing alexithymia, there was a decreased FAB. Further, the effects of interoceptive awareness were partially mediated by private rehearsal of pleasant events. We provide novel evidence that capacity for emotional awareness and thus effective processing is an important factor predictive of the FAB. Moreover, our results imply an important role for maintaining positive affect in the FAB. Our findings offer new insights into the effects of interoception and alexithymia on autobiographical memory, and support concepts of the FAB emerging as a result of adaptive emotional regulation processes. (shrink)

Awareness of internal bodily sensations and its connection to complex socioemotional abilities like empathy has been postulated, yet the functional neural circuitry they share remains poorly understood. The present fMRI study employs independent component analysis to investigate which empathy facet shares resting-state functional connectivity and/or BOLD variability with IA. Healthy participants viewed an abstract nonsocial movie demonstrated to evoke strong rsFC in brain networks resembling rest, and resultant rsFC and rsBOLD data were correlated with self-reported empathy and IA questionnaires. (...) We demonstrate a bidirectional behavioral and neurobiological relationship between empathy and IA, depending on the type of empathy interrogated: Affective empathy and IA share both rsFC and rsBOLD, while Cognitive empathy and IA only share rsBOLD. Specifically, increased rsFC in the right inferior frontal operculum of a larger attention network was associated with increased vicarious experience but decreased awareness of inner body sensations. Furthermore, increased rsBOLD between brain regions of an interoceptive network was related to increased sensitivity to internal sensations along with decreased Affective empathy. Finally, increased rsBOLD between brain regions subserving a mentalizing network related to not only an improved ability to take someone’s perspective, but also a better sense of mind-body interconnectedness. Overall, these findings suggest that the awareness of one’s own internal body changes is related to the socioemotional ability of feeling and understanding another’s emotional state and critically, that this relationship is reflected in the brain’s resting state neuroarchitecture. Methodologically, this work highlights the importance of utilizing rsBOLD as a complementary window alongside rsFC to better understand neurological phenomena. Our results may be beneficial in aiding diagnosis in clinical populations such as autism spectrum disorder, where participants may be unable to complete tasks or questionnaires due to the severity of their symptoms. (shrink)

Edited by Manos Tsakiris and Helena De Preester, (Oxford, Oxford University Press), 2019, 368 pages,To understand the nature of mind, cognitive scientists of all theoretical strands may benefit from considering experimental evidence of cognition (perception, attention, memory, etc.) alongside phenomenologies of (conscious) experiences and feelings-let's say, proprioceptive, exteroceptive, interoceptive, and bodily self-conscious. Roughly, the former dimension of scientific studies of mind seems to have found its legitimacy; however, at least, at first sight, the latter could still not be exonerated (...) completely. That is to say, as far as the scientifically evidence-based account of interoception is concerned, we will have come a long way towards buttressing its legitimacy. The Interoceptive Mind: From Homeostasis to Awareness (Tsakiris and De Preester, 2019) would be seen as a guide to scientific studies of interoception in all of the cases so far. In particular, the essays collected in this book shed light on multisensory integrations of interoceptive and exteroceptive feelings (and even self-conscious feelings) across widespread disciplines.As suggested in its title, the book addresses the difficulties of integrating various dimensions relevant to feelings-from the biological notion of self to the interoceptive origin of self-awareness. The book divides into four sections, and each chapter is worthy of careful attention.Part I, i.e., the first chapter introduces the histor... (shrink)

The processing, representation, and perception of bodily signals (interoception) plays an important role for human behavior. Theories of embodied cognition hold that higher cognitive processes operate on perceptual symbols and that concept use involves reactivations of the sensory-motor states that occur during experience with the world. Similarly, activation of interoceptive representations and meta-representations of bodily signals supporting interoceptive awareness are profoundly associated with emotional experience and cognitive functions. This article gives an overview over present findings and models (...) on interoception and mechanisms of embodiment and highlights its relevance for disorders that are suggested to represent a translation deficit of bodily states into subjective feelings and self-awareness. (shrink)

Addiction remains a challenging disorder, both to treat and to conceptualise. While the temporal dimension of addiction has been noted before, here the aim is to ground this understanding in a coherent phenomenological-neuroscience framework. Addiction is partly understood as drawing the subject into a predominantly “now” orientated existence, with the future closed or experienced as extremely distant. Another feature of this temporal structuring is that past experiences, which are crucial in advancing intentionally forward, are experienced in addiction as a void. (...) This has implications for the generation of meaning and forming of self, amongst others. While there are areas of the brain that regulate temporal processing, there is no single location. Recent addiction research has implicated the insula and in turn this area is implicated in temporal and interoceptive awareness. Similarly these areas of disruption may affect self processes. Disruption of interoception and thus of self, may help explain why addiction is complex and involves multiple aspects of subjectivity. (shrink)

Addiction remains a challenging disorder, both to treat and to conceptualise. While the temporal dimension of addiction has been noted before, here the aim is to ground this understanding in a coherent phenomenological-neuroscience framework. Addiction is partly understood as drawing the subject into a predominantly “now” orientated existence, with the future closed or experienced as extremely distant. Another feature of this temporal structuring is that past experiences, which are crucial in advancing intentionally forward, are experienced in addiction as a void. (...) This has implications for the generation of meaning and forming of self, amongst others. While there are areas of the brain that regulate temporal processing, there is no single location. Recent addiction research has implicated the insula and in turn this area is implicated in temporal and interoceptive awareness. Similarly these areas of disruption may affect self processes. Disruption of interoception and thus of self, may help explain why addiction is complex and involves multiple aspects of subjectivity. (shrink)

Background: Alexithymia is a personality trait which is characterized by an inability to identify and describe conscious emotions of oneself and others.Aim: The present study aimed to determine whether various measures of mental health, interoception, psychological flexibility, and self-as-context, predicted through linear associations alexithymia as an outcome. This also included relevant mediators and non-linear predictors identified for particular sub-groups of participants through cluster analyses of an Artificial Neural Network output.Methodology: Two hundred and thirty participants completed an online survey which included (...) the following questionnaires: Toronto alexithymia scale; Acceptance and Action Questionnaire 2 ; Positive and Negative Affect Scale, Depression, Anxiety, and Stress Scale 21 ; Multidimensional Assessment of Interoceptive Awareness ; and the Self-as-Context scale. A stepwise backwards linear regression and mediation analysis were performed, as well as a cluster analysis of the non-linear ANN upper hidden layer output.Results: Higher levels of alexithymia were associated with increased psychological inflexibility, lower positive affect scores, and lower interoception for the subscales of “not distracting” and “attention regulation.” SAC mediated the relation between emotional regulation and total alexithymia. The ANNs accounted for more of the variance than the linear regressions, and were able to identify complex and varied patterns within the participant subgroupings.Conclusion: The findings were discussed within the context of developing a SAC processed-based therapeutic model for alexithymia, where it is suggested that alexithymia is a complex and multi-faceted condition, which requires a similarly complex, and process-based approach to accurately diagnose and treat this condition. (shrink)

The mainstream science of consciousness offers a few predominate views of how the brain gives rise to awareness. Chief among these are the Higher-Order Thought Theory, Global Neuronal Workspace Theory, Integrated Information Theory, and hybrids thereof. In parallel, rapid development in predictive processing approaches have begun to outline concrete mechanisms by which interoceptive inference shapes selfhood, affect, and exteroceptive perception. Here, we consider these new approaches in terms of what they might offer our empirical, phenomenological, and philosophical understanding (...) of consciousness and its neurobiological roots. (shrink)

Current empirical work suggests that early social experiences could have a substantial impact on the areas of the brain responsible for representation of the body. In this context, one aspect of functioning that may be particularly susceptible to social experiences is interoception. Interoceptive functioning has been linked to several areas of the brain which show protracted post-natal development, thus leaving a substantial window of opportunity for environmental input to impact the development of the interoceptive network. We first introduce (...) a biopsychosocial model of interoceptive development. In our proposed model of interoceptive development, attachment related processes are purported to affect the development of interoception by influencing the growth of neural architecture and by modifying functioning of the HPA axis. Further, the idea that patterns of caretaking affect children’s development of interoception is presented. This model explains both normatively developing interoception and accounts for instances in which dysfunctional attachment related processes can lead to either a hypersensitivity or a blunted awareness of bodily cues. Second, we report findings from two existing datasets showing significant relationships between attachment related processes and interoception. In the first study, looking at a sample of healthy young adults (n = 132, 66 males), we assessed self-reported interoceptive awareness and attachment style. We found relationships between aspects of interoception and attachment style such that avoidant individuals reported lower interoceptive functioning across several dimensions (r’s (130) = -.20 to -.26, p’s<.05). More anxious individuals, on the other hand, reported heightened interoceptive across several dimensions (r’s(130)=.18 to.43, p’s <.05). In the second study, we examined the congruence between a person’s self-reported negative emotion and a measure of sympathetic nervous system arousal (SCL). The congruence score was positively associated with parental rejection of negative emotion. These results suggest that parenting style, as reported by the mother, are associated with a child’s ability to coordinate their self-reported emotional and physiological responding across a series of independent assessments, r(108)= -.24, p<.05. In other words, the more maternal reported parental rejection of child negative emotions, the less congruent a child’s self and physiological reports of distress. (shrink)

Interoception, the ability to feel the body’s internal sensations, is an essential aspect of emotional experience. There is mounting evidence that interoception is impaired in common mental health disorders and that poor interoceptive awareness is a major contributor to emotional reactivity, calling for clinical interventions to address this deficit. The manuscript presents a comprehensive theoretical review, drawing on multidisciplinary findings to propose a metatheory of reinforcement mechanisms applicable across a wide range of disorders. We present a reconsideration of (...) operant conditioning through the co-emergence model of reinforcement, which is a neurophenomenological account of the interaction between cognition and interoception, and its consequences on behavior. The model suggests that during memory processing, the retrieval of autobiographical memory (including maladaptive cognition) is dependent upon its co-emerging interoceptive cues occurring at the encoding, consolidation and reconsolidation stages. Accordingly, “interoceptive reinforcement” during emotional distress is a common factor to all emotional disorders and a major cause for relapse. We propose that interoceptive desensitization has transdiagnostic benefits, readily achievable through the cultivation of equanimity during mindfulness training and can be integrated in cognitive and behavioral interventions to permit a transdiagnostic applicability. We summarize the contributions of this approach into 10 specific and testable propositions. (shrink)

Risky behaviour may be associated with visceral experiences, such as increased heart rate. Previous studies examining the relationship between perception of such signals (interoception) and risk-taking typically used behavioural tasks with potential for monetary reward. This approach may be less informative for understanding general risk propensity. In addition, such research does not usually consider the varied ways individuals engage with interoceptive signals. However, examining these different forms of engagement may help us understand how subjective experience of interoception influences risk-taking. (...) As such, we performed two surveys (n = 471, primarily young adults) to examine the relationship between self-reported engagement with interoceptive signals (measured using the Multidimensional Assessment of Interoceptive Awareness) and a generalised measure of risk propensity (the General Risk Propensity Scale). Results indicated that different ways of interpreting or engaging with interoceptive signals were differentially associated with risk propensity. In particular, they provide preliminary evidence that those with the ability to ignore or not worry about visceral signals when they are uncomfortable display greater risk propensity (and these effects may possibly be gender-specific). (shrink)

Scholars and providers are coming to realize that one’s ability to notice and respond to internal body sensations contributes to an overall sense of wellbeing. Research has demonstrated a relationship between interoceptive awareness and anxiety, for example. Currently, however, tools for evaluating one’s interoception lack the conceptual foundation and clarity necessary to identify everyday behaviors that specifically reflect interoceptive awareness. Unlike existing interoceptive measures, the Sensory Profile Interoception scale is participation-based and grounded in Dunn’s Sensory (...) Processing framework. In this study we investigated concurrent validity by correlating the SPI with the Adolescent/Adult Sensory Profile ; we investigated construct validity by correlating the SPI with the Perth Alexithymia Scale, the Body Awareness Scale, and the State-Trait Anxiety Inventory. Using the REDCAP online platform, 74 college-aged participants completed the measures. Using Spearman rank order correlations there were statistically significant relationships between the corresponding sensory pattern subscales on SPI and A/ASP. The PAS was only weakly related to the registration subscale of the SPI. The BAS had significant relationships with seeking and avoiding on the SPI. The STAI had significant relationships with sensitivity and registrations of the SPI. Taken together, these findings provide evidence of construct validity of the SPI to identify participation patterns associated with both high and low interoception. With the more precise information the SPI provides, professionals can design tailored interventions to support everyday life goals and researchers can study interoception within authentic activities. (shrink)

This article focuses on the question of how we perceive and represent ourselves at the most minimal, pre-reflective level. We first review recent work emphasizing the multisensory basis of our perceptual experiences and the embodied nature of self-awareness. We then focus on interoceptive and tactile signals, as key components of bodily self-consciousness, and discuss one crucial yet overlooked aspect of our embodiment, namely the fact that bodily self-consciousness emerges from the outset within the body of another experiencing subject. (...) Next, we review empirical findings highlighting the developmental primacy of tactile and interoceptive over visual experiences, in shaping the foundations of perceptual awareness. Building upon the influential predictive processing framework in philosophy and theoretical neuroscience, we argue that self-awareness is not only embodied, but also that perceptual experiences are fundamentally 'selfish', that is, imperatively driven by basic constraints of physiological regulation that subserve self-preservation. We then evaluate. (shrink)

We become aware of our bodies interoceptively, by processing signals arising from within the body, and exteroceptively, by processing signals arising on or outside the body. Recent research highlights the importance of the interaction of exteroceptive and interoceptive signals in modulating bodily self-consciousness. The current study investigated the effect of social self-focus, manipulated via a video camera that was facing the participants and that was either switched on or off, on interoceptive sensitivity and on tactile perception ). The (...) results indicated a significant effect of self-focus on SSDT performance, but not on interoception. SSDT performance was not moderated by interoceptive sensitivity, although interoceptive sensitivity scores were positively correlated with false alarms, independently of self-focus. Together with previous research, our results suggest that self-focus may exert different effects on body perception depending on its mode . While interoception has been previously shown to be enhanced by private self-focus, the current study failed to find an effect of social self-focus on interoceptive sensitivity, instead demonstrating that social self-focus improves exteroceptive somatosensory processing. (shrink)

The purposes of the present study were to explore the relationship between body awareness and negative body attitude, interoceptive body awareness and physical self in women practicing fitness as well as to analyze the determinants of body awareness. The Body Awareness Questionnaire, the Multidimensional Assessment of Interoceptive Awareness, the Physical Self-Description Questionnaire and the Body Attitude Test were applied to 43 women practicing fitness and 32 non-fitness practitioners. Bodily self-awareness was connected with (...) greater fitness practitioners’ interoceptive body awareness and greater physical self. Noticing and global esteem predicted body awareness in women practicing fitness. (shrink)

Somatic awareness is bodily sensation imbued with consciousness. Directing and cultivating somatic awareness is a practice fundamental to many therapeutic and spiritual enterprises. Recent developments in neuroscience attempt to explain the operational aspects of somatic awareness. But it has long been a topic of conversation in other paradigms, from philosophy to health care. Somatic input provides information for use in wellness treatment applications, including therapeutic bodywork. Yet few massage therapy scholarly investigations aim to capture the quality of (...) body awareness experience. The essence of the experience and its associated language remain imprecise and under-explored holistically.This article implements the therapeutic practice technique of the Body Scan to capture the essence of an inner body exploration (proprioception and interoception). Based on a narrative collected during a verbally self-directed exercise, a phenomenological description is explicated to represent one incidentof internal body experience. The pilot study suggests that the Body Scan offers potential as a research tool, as well as a modality for therapeutic intervention. (shrink)

Research on bodily awareness has focused on body illusions with an aim to explore the possible dissociation of our bodily awareness from our own body. It has provided insights into how our sensory modalities shape our sense of embodiment, and it has raised important questions regarding the malleability of our sense of ownership over our own body. The issue, however, is that this research fails to consider an important distinction in how we experience our body. There are indeed (...) two ways in which we can be aware of our body: via observational awareness, which involves attending to the body as an object, and via non-observational awareness, where the body is given as the subject of experience and does not involve attention. The research to date has focused on the former—observational bodily awareness—and has left the latter—non-observational bodily awareness—in the dark. This is detrimental to ever formulating a complete account of how we are aware of our body. It is understandable, however, because of the inherent problem in studying non-observational bodily awareness: how would you instruct subjects to report on their unattended bodily awareness? In view to resolving this problem, I propose here a working hypothesis on the basis of research on interoception and the rubber hand illusion, and on the effect of meditation on awareness and attention. This working hypothesis can show us a way to begin studying non-observational bodily awareness, and finally build a complete theory of bodily awareness. (shrink)

Depersonalization is a pathological condition consisting in a deep modification of the way things appear to a subject, leading him to feel estranged from his body, his actions, his thoughts, his mind and even from himself. In this article, I argue that the study of depersonalization raises three challenges for recent theories of the sense of bodily ownership. These challenges—which I call the centrality challenge, the dissociation challenge and the grounding challenge— thwart most of these theories and suggest that the (...) sense of bodily ownership hinges on a phenomenal mark of mineness that can not be accounted for in terms of our sensory, interoceptive, agentive, cognitive or affective dispositions and that is psychologically primitive. In short: that mineness is first. (shrink)

Interoception in the broader sense refers to the perception of internal states, including the perception of the actual state of the internal organs and the motor system. Dimensions of interoception include interoceptive accuracy, i.e., the ability to sense internal changes assessed with behavioral tests, confidence rating with respect to perceived performance in an actual behavioral test, and interoceptive sensibility, i.e., the self-reported generalized ability to perceive body changes. The relationship between dimension of cardioceptive and proprioceptive modalities and their (...) association with affect are scarcely studied. In the present study, undergraduate students filled out questionnaires assessing positive and negative affect, interoceptive sensibility, and body competence. Following this, they completed a behavioral task assessing cardioceptive accuracy and two tasks assessing proprioceptive accuracy with respect to the tension of arm flexor muscles and the angular position of the elbow joint. Confidence ratings were measured with visual analog scales after the tasks. With the exception of a weak association between cardioceptive accuracy and the respective confidence rating, no associations between and within modalities were found with respect to various dimensions of interoception. Further, the interoceptive dimensions were not associated with state and trait positive and negative affect and perceived body competence. In summary, interoceptive accuracy scores do not substantially contribute to conscious representations of cardioceptive and proprioceptive ability. Within our data, non-pathological affective states are not associated with the major dimensions of interoception for the cardiac and proprioceptive modalities. (shrink)

Reduced Environmental Stimulation Therapy (REST) alters the balance of sensory input to the nervous system by systematically attenuating sensory signals from visual, auditory, thermal, tactile, vestibular, and proprioceptive channels. Previous research from our group has shown that REST via floatation acutely reduces anxiety and blood pressure while simultaneously heightening interoceptive awareness in clinically anxious populations. Anorexia nervosa (AN) is an eating disorder characterized by elevated anxiety, distorted body representation, and abnormal interoception, raising the question of whether REST might (...) positively impact these symptoms. However, this approach has never been studied in eating disorders and it is unknown whether exposure to REST might worsen AN symptoms. To examine these possibilities we conducted an open-label study to investigate the safety and tolerability of REST in AN. We also explored the impact of REST on affective symptoms, body image disturbance, and interoception. Twenty-one partially weight-restored AN outpatients completed a protocol involving four sequential sessions of REST: reclining in a zero-gravity chair, floating in an open pool, and two sessions of floating in an enclosed pool. All sessions were 90 minutes, approximately one week apart. We measured orthostatic blood pressure before and immediately after each session (primary outcome), in addition to collecting blood pressure readings every 10 minutes during the session using a wireless waterproof system as a secondary outcome measure. Each participant's affective state, awareness of interoceptive sensations, and body image was assessed before and after every session (exploratory outcomes). There was no evidence of orthostatic hypotension following floating, and no adverse events (primary outcome). Secondary analyses revealed that REST induced statistically significant reductions in blood pressure, anxiety and negative affect, heightened awareness of cardiorespiratory but not gastrointestinal sensations, and reduced body image dissatisfaction. The findings from this initial trial suggest that individuals with AN can safely tolerate the physical effects of REST via floatation. Future randomized controlled trials will need to investigate whether these initial observations of improved anxiety, interoception, and body image disturbance can be effectively extended to acutely ill AN populations. (shrink)