Heart rate perception and expectation impact laboratory-induced perceived stress

Previous studies have shown that the human capacity to gauge one's own physiological state is notoriously flawed. The cause for the mismatch between perceived and physiological stress has not yet been properly identified. In this study, we assumed that cardioceptive accuracy (CAc) is positively associated with cardiovascular reactivity, and CAc and expectation about stress might account for the discrepancy between perceived and physiological stress. In a crossover experiment, we assessed cardioceptive accuracy in two ways (mental heartbeat tracking task and perception of heart rate), and induced physiological (handgrip exercise) and mental (N-back task) stress in 64 university students (51 % male, mean age 22.2). We assessed cardiac and electrodermal activity, and expected and perceived stress. We found that indicators of cardioceptive accuracy were not associated with cardiovascular reactivity. However, heart rate perception moderated the association between the change in heart rate and perceived stress in the physical but not in the mental task. Whereas heartbeat tracking accuracy was not associated with perceived stress. Moreover, perceived stress was predicted by the expected stress but not by the change in heart rate and electrodermal activity in the mental stress task. In conclusion, heart rate perception and expectation of stress may shape perceived stress more than actual physiological changes in moderate acute stress.

Heart is deceitful above all things: Threat expectancy induces the illusory perception of increased heartrate

It has been suggested that our perception of the internal milieu, or the body's internal state, is shaped by our beliefs and previous knowledge about the body's expected state, rather than being solely based on actual interoceptive experiences. This study investigated whether heartbeat perception could be illusorily distorted towards prior subjective beliefs, such that threat expectations suffice to induce a misperception of heartbeat frequency. Participants were instructed to focus on their cardiac activity and report their heartbeat, either tapping along to it (Experiment 1) or silently counting (Experiment 2) while ECG was recorded. While completing this task, different cues provided valid predictive information about the intensity of an upcoming cutaneous stimulation (high- vs. low- pain). Results showed that participants expected a heart rate increase over the anticipation of high- vs. low-pain stimuli and that this belief was perceptually instantiated, as suggested by their interoceptive reports. Importantly, the perceived increase was not mirrored by the real heart rate. Perceptual modulations were absent when participants executed the same task but with an exteroceptive stimulus (Experiment 3). The findings reveal, for the first time, an interoceptive illusion of increased heartbeats elicited by threat expectancy and shed new light on interoceptive processes through the lenses of Bayesian predictive processes, providing tantalizing insights into how such illusory phenomena may intersect with the recognition and regulation of people's internal states.

Heart activity perception: narrative review on the measures of the cardiac perceptual ability

Measures of cardiac perceptual ability (also called cardiac accuracy) are methods of cardiac interoception, the perception of bodily sensation related to heart activity. This narrative review aims to provide an overview of these methods. We differentiate between three main measurement types: (1) change detection, i.e., when the task is to notice the change in the heart rate; also called: heart rate perception tasks, (2) discrimination tasks, i.e., when the task is to compare the internal sensations with external signal(s); also called: heartbeat detection tasks and (3) tracking tasks, i.e., when the task is to follow and report heartbeats via tapping or counting. We describe some of the new methods under "mixed methods," as they share features with more than one of the large measurement types described above. Specific measures differ in various aspects, such as their focus (heart rhythm vs. single beats), their sensitivity to non-conscious sensations and the calculated indices (e.g., whether significance level by hypothesis test is provided). When a measure of cardiac perceptual ability is chosen, it is advisable to take its characteristics into consideration in light of the planned research.

Seeing Through Each Other's Hearts: Inferring Others' Heart Rate as a Function of Own Heart Rate Perception and Perceived Social Intelligence

Successful social interactions require a good understanding of the emotional states of other people. This information is often not directly communicated but must be inferred. As all emotional experiences are also imbedded in the visceral or interoceptive state of the body (i.e., accelerating heart rate during arousal), successfully inferring the interoceptive states of others may open a window into their emotional state. But how well can people do that? Here, we replicate recent results showing that people can discriminate between the cardiac states (i.e., the resting heartrate) of other people by simply looking at them. We further tested whether the ability to infer the interoceptive states of others depends on one's own interoceptive abilities. We measured people's performance in a cardioception task and their self-reported interoceptive accuracy. Whilst neither was directly associated to their ability to infer the heartrate of another person, we found a significant interaction. Specifically, overestimating one's own interoceptive capacities was associated with a worse performance at inferring the heartrate of others. In contrast, underestimating one's own interoceptive capacities did not have such influence. This pattern suggests that deficient beliefs about own interoceptive capacities can have detrimental effects on inferring the interoceptive states of other people.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42761-022-00151-4.

Embodied feelings-A meta-analysis on the relation of emotion intensity perception and interoceptive accuracy

Emotion theories emphasize the relevance of (predicted) bodily changes for the construction of one's own emotions and an extensive overlap of brain regions involved during emotion intensity perception and somatosensory processing. The ability to accurately perceive bodily changes and its impact on the perception of emotion intensity has been studied for at least 40 years. The results of previous studies were summarized in a meta-analysis to examine how closely interoceptive accuracy and emotion intensity are related. After a systematic literature search, 4036 studies were screened for eligibility. Only studies assessing adults from general population samples were considered. Samples recruited to examine mental disorders or neurological conditions were excluded. Thirty studies with a quantifiable measure for the relation of interoceptive accuracy and emotion intensity perception were included in the meta-analysis. Interoceptive accuracy was significantly related with emotion intensity perception, when emotions were experimentally induced (k= 22, r= 0.15). However, the relationship was only found when IAPS images (k= 9, r= 0.33) or facial expressions (k= 3, r= 0.24) were used for emotion induction. No significant relation was found in studies without emotion induction (k= 19, r = -0.007). There was considerable bias, varying dependent on bias assessment method, study protocol and examined risk of bias dimension. We discuss the impact of differences in study protocols, review the operationalization of interoceptive accuracy critically and derive directions for future research.

Mediterranean Diet, Interoception and Mental Health: Is it time to look beyond the 'Gut-Brain Axis'?

OBJECTIVE

A Mediterranean style diet (i.e., high in fruit, vegetables, fish, pulses, and wholegrains) is said to benefit psychological health. Many low-level interoceptive processes, such as those involved in the 'gut-brain' axis, are suggested to play a mechanistic role in in this relationship. However, interoceptive sensations in other domains, and at higher hierarchical levels of abstraction, have hitherto been overlooked. One domain often studied in relation to psychological health is cardioception. Therefore, we examined whether the Mediterranean diet was associated with first-order perceptual and second-order metacognitive cardioception.

METHODS

Participants completed the Heartbeat Detection Task, the Heartbeat Counting Task, and the EPIC-Norfolk Food Frequency Questionnaire from which diet was quantified.

RESULTS

Adherence to a Mediterranean style diet was associated with higher cardioceptive accuracy (i.e., perceptual performance) across both tasks. In addition, those consuming a Mediterranean diet had a better ability to detect errors in first order perceptual performance, and a lower prediction error (the magnitude of the difference between accuracy and confidence).

DISCUSSION

These findings indicated that deepening our understanding of how interoceptive processes beyond the 'gut-brain' axis are shaped by diet could deepen our understanding of the link between diet and mental health and wellbeing.

Expectation predicts performance in the mental heartbeat tracking task

The mental heartbeat tracking task by Schandry is sensitive to non-interoceptive (top-down) influences, e.g., estimation of heart rate and expectation. The two studies reported here investigated the impact of these factors on the outcome of the task. In Study 1, performance-related expectation was assessed between the training interval and the real trials. Performance was strongly related (β = .595, p < .001) to expectation even after controlling for sex, body fat, resting heart rate and estimation of heart rate. In Study 2, expectation was assessed before and after the training interval for Group 1 and 2, respectively. The strong association (r = 0.78, p < .001) between performance and expectation was replicated for Group 2; however, a moderate association (r = 0.39, p < .01) was also found in Group 1. People with high expectation may be prone to categorize and count vague sensations, such as attention evoked sensations, as heartbeats; this can lead to an inflated Schandry-score.

Interoceptive accuracy is associated with emotional contagion in a valence- and sex-dependent manner

Over the last years, the neurobiological mechanisms of empathy have been extensively investigated. Recent investigations suggest that interoceptive processes, in particular, those that are related to the experience and perception of cardiac changes, are relevant for affect sharing, mentalizing and self-other distinction. To further investigate the association between interoception and affect-sharing, we measured emotional contagion and interoceptive accuracy in a sample of healthy participants (n = 84). Emotional contagion was assessed with an established self-report questionnaire and interoceptive accuracy was assessed with a validated heartbeat detection task. Across a series of complementary analyses, we found a sex- and valence-dependent association between interoception and affection sharing: Among female but not male participants, interoceptive accuracy was positively associated with emotional contagion for negative but not positive states of others. We provide an evolutionary-based explanation for these findings, which are consistent with previous findings showing positive associations between interoceptive accuracy, mentalizing and self-other distinction.

Sense it and use it: interoceptive accuracy and sensibility in suicide ideators

BACKGROUND

Interoceptive deficits have been found to be associated with suicidal ideation and behavior. However, an objective measure of interoceptive accuracy has not been investigated in participants with suicide ideation, by now. This study aimed at investigating interoceptive accuracy and sensibility in persons with and without suicide ideation (SI) while controlling for severity of depressive symptoms.

METHOD

Ninety-five participants (age: M = 34.8, SD = 11.6, n = 56 female [58.9%]; n = 51 patients with a Major Depressive Disorder and n = 44 healthy participants) were assessed for interoceptive accuracy and sensibility, depression and SI.

RESULTS

Twenty-five participants (26%) reported SI. They showed interoceptive accuracy comparable to persons without SI (t = -.81, p = .422), but significantly lower interoceptive sensibility. After controlling for severity of depressive symptoms in a hierarchical linear regression analysis, most associations between interoceptive sensibility and SI disappeared.

CONCLUSION

Results suggest that suicide ideators do not lack the ability to perceive their own bodily signals but they feel less able to use them in a way that is advantageous for them. Differences between suicide ideators and non-ideators appear to be largely driven by depressive symptoms (depression bias).

Interoceptive Accuracy in Youth with Tic Disorders: Exploring Links with Premonitory Urge, Anxiety and Quality of Life

Aberrant interoceptive accuracy could contribute to the co-occurrence of anxiety and premonitory urge in chronic tic disorders (CTD). If it can be manipulated through intervention, it would offer a transdiagnostic treatment target for tics and anxiety. Interoceptive accuracy was first assessed consistent with previous protocols and then re-assessed following an instruction attempting to experimentally enhance awareness. The CTD group demonstrated lower interoceptive accuracy than controls but, importantly, this group difference was no longer significant following instruction. In the CTD group, better interoceptive accuracy was associated with higher anxiety and lower quality of life, but not with premonitory urge. Aberrant interoceptive accuracy may represent an underlying trait in CTD that can be manipulated, and relates to anxiety and quality of life.

Fear of hypoglycemia in patients with type 2 diabetes: The role of interoceptive accuracy and prior episodes of hypoglycemia

OBJECTIVE

Fear of hypoglycemia (FoH) is a limiting factor for diabetes self-management and can have detrimental effects on quality of life. However, relatively little is known about its underlying mechanisms. In line with findings on patients with anxiety disorders, we hypothesized that interoceptive accuracy (IA) might be positively linked to FoH in patients with type 2 diabetes (T2DM).

METHODS

133 patients with T2DM were screened according to the extreme quartiles of the Hypoglycemia Fear Survey worry subscale (HFS-W). Overall, 66 participants (HFS-W<4; HFS-W>17) were included in the present study. Participants completed questionnaires on sociodemographic and diabetes-related measures. Accuracy of heartbeat perception was assessed using the mental tracking task.

RESULTS

Contrary to expectations, IA did not differ significantly between patients with low and high FoH. A linear regression analysis demonstrated that the experience of mild hypoglycemia (β=0.32, p≤0.01) and its interaction with IA (β=-0.26, p=0.040) were significant predictors of FoH, indicating that low IA and a history of experiencing mild hypoglycemia are positively associated with FoH.

CONCLUSION

Our findings suggest a positive association of low IA in combination with prior episodes of hypoglycemia and FoH in patients with T2DM. The results are in line with recent findings on IA in patients with chronic somatic symptom distress more generally and contribute to our understanding of the relations between interoception, body related fears, and physical symptom perception.

The impact of olfactory dysfunction on interoceptive awareness

This study aimed to investigate how the impairment of the olfactory system influences interoception. Interoception is known as the awareness of one's body or the sense of the condition of the body; more precisely, this construct is defined as the processing, representation, and perception of the internal physical state. Interoceptive sensitivity and chemosensory performance were assessed in 77 subjects, including 43 functional anosmics, 18 hyposmics, and 16 healthy controls. Interoceptive awareness was predicted by odor detection threshold, as well as the duration of olfactory loss in patients who suffered from reduced olfactory function-the longer the olfactory impairment, the worse the perception of bodily signals. The results of this study will significantly contribute to the basic understanding of the multifaceted effects of olfactory alterations.

Health anxiety--an indicator of higher interoceptive sensitivity?

BACKGROUND AND OBJECTIVES

According to cognitive-behavioral models, health anxiety arises from the misattribution of normal bodily sensations as signs of a severe illness. Consequently, higher levels of interoceptive accuracy might be critically involved in the development of health anxiety.

METHODS

To test this central assumption of cognitive behavioral models of health anxiety, we assessed interoceptive accuracy in a sample of college students (N = 100). Two interoceptive tasks (detection of one's own heartbeat using the Schandry paradigm and detection of nonspecific skin conductance fluctuations, NSCFs) were used.

RESULTS

We found no indication for a positive association between facets of health anxiety and a higher interoceptive accuracy in the two tasks. In fact, worse heartbeat perception was associated with higher health anxiety as measured by two questionnaires whereas perception of NSCFs was not significantly related to any facet of health anxiety. In addition, we found a bias to overestimate NSCFs in people with heightened health anxiety.

LIMITATIONS

Because a sample of college students served as participants, the generalization of the findings is limited and further studies in patients with the diagnosis of hypochondriasis are necessary.

CONCLUSIONS

The findings of both interoceptive paradigms suggest that health anxiety is not associated with better but rather with less accurate and biased interoceptive sensitivity. Probably, not a heightened interoceptive sensitivity but rather the bias in overestimating harmless somatic cues is more relevant for the maintenance of health anxiety. Our results are in line with recent research in other somatoform disorders.

Being watched: the effect of social self-focus on interoceptive and exteroceptive somatosensory perception

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 (using a heartbeat perception task) and on tactile perception (using the Somatic Signal Detection Task (SSDT)). 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 (private versus social). 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.