Physiological responses to acute stress and the drive to eat: The impact of perceived life stress

Stress-related eating in pregnancy? An RCT examining links between prenatal stress and food choices

BACKGROUND

Diet quality during pregnancy is important for maternal health and offspring development. However, national dietary recommendations are not always met. A potential barrier for healthy food choices might be the experience of stress. Previous literature in non-pregnant populations suggests a negative effect of acute stress on diet quality. This preregistered study is the first to test whether an acute stressor leads to unhealthy food choices in pregnancy and examine the moderating role of stress, depressive and anxiety complaints in daily life.

METHOD

Pregnant women (N = 110, 3rd trimester) completed online self-reported surveys measuring stress, depressive and anxiety complaints in daily life. Hereafter, participants were invited for a laboratory visit, in which they were exposed to the Trier Social Stress Test or a control task. After this manipulation, self-reported and actual food choices and food intake were assessed. At the end of the visit, a hair sample was collected. Throughout the visit, visual analogue scales on negative affect were completed and saliva samples were collected.

RESULTS

The stress group experienced significantly more psychological stress than the control group during the experimental manipulation. Main regression analyses showed that the acute laboratory stressor did not cause unhealthy food choices in the third trimester of pregnancy. In fact, the stress group chose fewer unhealthy foods and consumed fewer kilocalories compared to the control group. Additionally, the findings point at a moderating role of depressive and stress complaints in daily life on food choices within the control group: higher scores were related to more unhealthy food choices and more kilocalories consumed.

DISCUSSION

As this was the first study to test the effect of an acute stressor on food choices in pregnant women, more research is needed to obtain a better understanding of stress-related eating in pregnancy. This knowledge may inform future interventions to support pregnant women in improving their diet quality.

Lifetime stressor exposure is associated with greater rewarding effects of stress-related eating

Acute stressors tend to shift preferences toward comfort foods, yet they do not ubiquitously increase the amount of food consumed. Moreover, although many individuals eat more under stress, others eat less or show no change. Although the precise mechanisms explaining this variability in stress-related eating are unknown, they may be driven by individual differences in the rewarding effects of comfort eating, which are enhanced by greater lifetime stressor exposure. To investigate this possibility, we examined whether differences in lifetime stressor exposure predicted reductions in negative affect following snacking (i.e., negative reinforcement) and if this effect was specific to stress-related snacking or snacking in general. Participants were 26 women (23% non-White) between 20 and 45 years old (M = 31), with a mean body mass index of 26, who completed three laboratory visits. Participants completed an assessment of lifetime stressor exposure (i.e., STRAIN) on the first visit and, on two subsequent laboratory visits in counterbalanced order, were given snacks after an acute social stress task (i.e., TSST) or rest period. Greater lifetime stressor exposure was related to greater post-ingestive decreases in negative affect following the acute social stressor but not following the rest period. If stress-related eating is more comforting for women with greater lifetime stressors and contributes to a stronger stress-eating association, then this may inform obesity-related clinical treatments that target behaviors and cognitions related to reward-based learning.

The relationship between family function and the incidence of overweight/obesity in children and adolescents in Chengdu city, Sichuan province of China: based on latent profile analysis

BACKGROUND

Overweight/obesity in children and adolescents has become a global health problem, and family function may be associated with its occurrence. Studies exploring the association between family function and overweight/obesity in children and adolescents were performed in Western and Taiwan, China. To date, related studies haven't been conducted in Mainland China.

OBJECTIVES

To investigate the current status of overweight, obesity, and family function among children and adolescents in Chengdu, China, and to explore their associations.

METHODS

Children and adolescents in five primary and middle schools were chosen by cluster sampling. Body Mass Index was used to measure the status of overweight and obesity, and the Chinese family assessment instrument was adopted to assess family function. Latent profile analysis and stepwise logistic regression were applied to identify family classification and explore the relationships between family function and overweight/obesity.

RESULTS

A total of 7616 (84.92%) children and adolescents out of 8968 completed the study with qualified-filled questionnaires. Nine hundred and sixty-six (12.68%)participants were overweight and 656 (8.61%) were obese. The family function was categorized into three profiles: mild (63.93%), moderate (12.32%), and severe (23.75%) dysfunction. The prevalence of overweight was 12.16%, 14.71%, and 13.05% for mild, moderate, and severe family dysfunction, respectively. And the prevalence of obesity was 8.19%, 10.77%, and 8.62% respectively. Participants in moderate and severe dysfunction families were more likely to be overweight (moderate: OR = 1.27, 95% CI:1.01 ~ 1.59, P = 0.04; severe: OR = 1.38, 95% CI:1.15 ~ 1.66, P = 0.001) and obese (moderate: OR = 1.35, 95% CI:1.02 ~ 1.79, P = 0.03; severe: OR = 1.55, 95% CI:1.23 ~ 1.96, P < 0.001). Sociodemographic data such as gender, residence, grade, pocket money per week, the number of siblings, and the education level of the mother were all associated with the risk of being overweight/obese in children and adolescents.

CONCLUSIONS

The problems of being overweight or obese exist among children and adolescents in Chengdu. And the risk of being overweight or obese increases along with the decrease in family function.

Acute and Chronic Stress Associations With Blood Pressure: An Ecological Momentary Assessment Study on an App-Based Platform

OBJECTIVE

This study examined the within- and between-person associations of acute and chronic stress with blood pressure (BP) and heart rate (HR) using an app-based research platform.

METHODS

We examined data from 31,964 adults (aged 18-90 years) in an app-based ecological momentary assessment study that used a research-validated optic sensor to measure BP.

RESULTS

Within-person associations revealed that moments with (versus without) acute stress exposure were associated with higher systolic (SBP; b = 1.54) and diastolic BP (DBP; b = 0.79) and HR ( b = 1.53; p values < .001). During moments with acute stress exposure, higher acute stress severity than usual was associated with higher SBP ( b = 0.26), DBP ( b = 0.09), and HR ( b = 0.40; p values < .05). During moments without acute stress, higher background stress severity than usual was associated with higher BP and HR (SBP: b = 0.87, DBP: b = 0.51, HR: b = 0.69; p values < .001). Between-person associations showed that individuals with more frequent reports of acute stress exposure or higher chronic stress severity had higher SBP, DBP, and HR ( p values < .05). Between-person chronic stress severity moderated within-person physiological responses to stress such that individuals with higher chronic stress severity had higher average BP and HR levels but showed smaller responses to momentary stress.

CONCLUSIONS

Technological advancements with optic sensors allow for large-scale physiological data collection, which provides a better understanding of how stressors of different timescales and severity contribute to momentary BP and HR in daily life.

Do categorically distinct stressors alter the attention to visual food cues?

Stressor exposure affects food intake as well as the preference for high or low palatability foods, but little is known about how stressor types impact the visual attention to food images. We used eye tracking methodology in humans to determine if activation of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system is associated with changes in attention to food images as determined by measuring changes in oculomotor activity. Specifically, we tested two questions: 1) Do categorically distinct stressors alter aspects of visual attention to food images as determined by oculomotor activity (i.e., saccade latency, gaze duration, and saccade bouts)? 2) Do categorically distinct stressors differentially affect visual attention to food images of high or low palatability? A total of sixty participants were randomly divided into one of three test groups: controls, an anticipatory stressor group, or a reactive stressor group. We measured salivary cortisol and salivary alpha-amylase (sAA) before and after stressor exposure to confirm activation of the HPA axis and sympathetic nervous system, respectively. Following stressor exposure participants performed an eye-tracking test using a standardized food picture database (Food-pics). We analyzed saccade latency, gaze duration, and saccade bouts in balanced pairs of food and non-food images. Salivary cortisol was elevated by both stressors, although the elevation in salivary cortisol to the reactive stressor was driven by women only. sAA was elevated only by the anticipatory stressor. There were main effects of image type for all three eye-tracking variables, with initial saccades of shorter latency to food images and longer gaze duration and more saccade bouts with food images. Participants exposed to the reactive stressor reduced gaze duration on food images relative to controls, and this affect was not linked to palatability or salivary cortisol levels. We conclude that the reactive stressor decreased time spent looking at food, but not non-food, images. These data are partly consistent with the idea that reactive stressors reduce attention to non-critical visual signals.

Relations among perceived stress, fatigue, and sleepiness, and their effects on the ambulatory arterial stiffness index in medical staff: A cross-sectional study

Objective

To explore the relations among perceived stress, fatigue, sleepiness, and the pathway of their effects on the ambulatory arterial stiffness index (AASI) among medical staff.

Methods

This cross-sectional study was conducted at a tertiary hospital in Wuhan, China. Perceived stress, fatigue, and sleepiness were measured using the perceived stress scale (PSS), Fatigue assessment scale (FAS), and Epworth Sleepiness Scale (ESS), respectively. AASI was obtained from 24-h ambulatory blood pressure monitoring. Path analysis was used to clarify the relations among the PSS, FAS, and ESS scores, and their relations to AASI values.

Results

A total of 153 participants were included herein. The PSS and FAS correlated with the ESS (r = 0.424, p < 0.001), and the PSS correlated with the FAS (r = 0.614, p < 0.001). In addition, the ESS correlated with the AASI (r = 0.225, p = 0.005). According to the path analysis results, the PSS and FAS had no direct effect on the AASI, but did have an indirect effect on this index (β = 0.059, 95% confidence interval [CI] = 0.017-0.128, p = 0.005; β = 0.059, 95%CI = 0.016-0.135, p = 0.006, respectively) by influencing the ESS (β = 0.263, β = 0.262, p = 0.004).

Conclusion

Sleepiness was a mediator of the effects of perceived stress and fatigue on AASI.

Stress and eating responses in adolescent females predisposed to obesity: A pilot and feasibility study

OBJECTIVE

To explore how chronic stress, reactivity to acute stress, and obesogenic eating are linked in adolescent females predisposed to obesity.

METHODS

Participants included 21 adolescent females (m_age = 14.57 years) and their biological mothers with obesity (body mass index [BMI] ≥ 30 kg/m²). The pilot and feasibility study involved adolescent self-report of chronic stress, an acute stress-induction paradigm (Trier Social Stress Task, TSST), salivary cortisol collection to assess stress reactivity, and both subjective (self-report) and objective (snack buffet) measures of obesogenic eating.

RESULTS

Adolescent females reporting high chronic stress were significantly more likely to engage in self-reported emotional and external eating and to have higher food cravings (p's < .05) compared to adolescents with low chronic stress. Effect size estimates suggested a blunting effect of cortisol in the high chronic stress group. Blunted cortisol reactivity significantly predicted higher self-reported food cravings for the high chronic stress group (p = .04). Associations among chronic stress, cortisol, and self-reported and objective obesogenic eating reflected medium to large effect sizes.

CONCLUSIONS

This study built on limited extant research on stress and eating to demonstrate that chronic stress was associated with self-reported obesogenic eating patterns in adolescent females predisposed to obesity. Different patterns of cortisol reactivity and eating emerged depending on chronic stress group (low versus high). Understanding these eating patterns in the context of chronic stress can inform interventions to reduce obesity risks in adolescence.

Self-compassion, Stress, and Eating Behaviour: Exploring the Effects of Self-compassion on Dietary Choice and Food Craving After Laboratory-Induced Stress

BACKGROUND

Stress has been linked to high-fat and high-sugar food consumption. Self-compassion is associated with better emotional and physiological responses to stress. The current study explored whether trait self-compassion or induced state self-compassion could improve dietary choice and food craving after a stress induction.

METHOD

Fifty-three university students completed an online survey assessing self-compassion, eating restraint, and general perceived stress before attending a laboratory visit. In the laboratory, participants were randomised to a neutral writing control or a self-compassion letter writing condition before a stress induction. Measures of heart rate, heart rate variability, state self-compassion, dietary choice, and state food cravings were taken.

RESULTS

The brief self-compassion intervention did not sufficiently increase state self-compassion in the intervention group compared to the neutral writing condition. There was no effect of the written self-compassion intervention on heart rate, heart rate variability, dietary choice, or food craving. However, higher trait self-compassion was associated with healthier dietary choices (F(1, 49) = 5.35, p = .025, R² = .098).

CONCLUSION

Results suggest that higher trait self-compassion improved dietary choice after stress in a controlled environment in a university population. Further research is warranted to explore whether brief self-compassion interventions can improve state self-compassion and thereby influence dietary choices and food cravings after a stress induction.

Vascular-Metabolic Risk Factors and Psychological Stress in Patients with Chronic Tinnitus

Little is known about molecular correlates of chronic tinnitus. We examined interrelationships between vascular−metabolic risk factors, perceived stress, and other routine blood values in patients with chronic tinnitus. Two-hundred patients (51% female) were screened for 49 blood parameters pertaining to vascular−metabolic risk, immune function, and redox processes. They further completed perceived stress- and tinnitus-related distress questionnaires. Following descriptive analyses, gender-specific sets of age- and tinnitus-severity-adjusted regression models investigated associations between perceived stress and blood parameters. Patients reported mildly elevated levels of perceived stress. Elevated levels of total cholesterol (65% and 61% of female and male patients, respectively), non-HDL-c (43/50%), LDL-c (56/59%), and lipoprotein_a (28/14%) were accompanied by high rates of overweight (99/100%) and smoking (28/31%). A low-level inflammatory state was accompanied by reduced reactive oxygen species (ROS)-neutralizing capacity (reduced co-enzyme Q10 and SOD1 levels). Most vascular risk factors were not correlated with perceived stress, except for fibrinogen (ß = −0.34) as well as C-reactive protein (ß = −0.31, p < 0.05) in men, and MCV (ß = −0.26, p < 0.05) in women. Interrelations between blood parameters and stress levels need to be investigated within psychobehavioural frameworks across varying distress levels. Alongside psychological interventions, a low-level inflammatory state may be a route for pharmacological therapeutics.

A Framework for Developing Translationally Relevant Animal Models of Stress-Induced Changes in Eating Behavior

Stress often affects eating behaviors, leading to increased eating in some individuals and decreased eating in others. Identifying physiological and psychological factors that determine the direction of eating responses to stress has been a major goal of epidemiological and clinical studies. However, challenges of standardizing the stress exposure in humans hinder efforts to uncover the underlying mechanisms. The issue of what determines the direction of stress-induced feeding responses has not been directly addressed in animal models, but assays that combine stress with a feeding-related task are commonly used as readouts of other behaviors, such as anxiety. Sex, estrous cyclicity, circadian cyclicity, caloric restriction, palatable diets, elevated body weight, and properties of the stressors similarly influence feeding behavior in humans and rodent models. Yet, most rodent studies do not use conditions that are most relevant for studying feeding behavior in humans. This review proposes a conceptual framework for incorporating these influences to develop reproducible and translationally relevant assays to study effects of stress on food intake. Such paradigms have the potential to uncover links between emotional eating and obesity as well as to the etiology of eating disorders.

When the mind says one thing, but the HPA axis says another: Lack of coherence between subjective and neuroendocrine stress response trajectories in healthy men

Psychological stress triggers the release of cortisol following the activation of the hypothalamic-pituitary-adrenal (HPA) axis and elicits concomitant subjective responses. Coherence among the stress response systems is theoretically expected, presumably to optimize the organism's response to environmental challenges, but has received little empirical support possibly due to the assumption of linear associations. The present study examined the associations between cortisol responses to the Maastricht Acute Stress Test (MAST) and concomitant subjective stress responses as well as mood states over the past weeks in 133 healthy men. Latent class growth analysis (LCGA) was applied on individual cortisol and subjective stress responses to identify homogeneous response trajectories within the larger heterogeneous population and enable testing non-linear relationships while retaining the temporal resolution of the stress responses. LCGA revealed four latent cortisol response classes, labeled as mild responders (n = 15), moderately-low responders (n = 46), moderately-high responders (n = 48), and hyper responders (n = 24). These latent classes were not associated with concomitant subjective stress responses. Similarly, the three distinct latent classes capturing the variability in subjective stress responses were also not associated with concomitant cortisol responses. Experiencing higher levels of stress over the previous weeks, however, increased the likelihood of exhibiting a hyper cortisol stress response profile. Positive and negative affective states, and anxious and depressive symptomology over the previous weeks were not associated with cortisol response trajectories. Contrary to previous findings supporting a quadratic association in healthy females, our results do not support the response coherence hypothesis in healthy males subjected to the MAST, but suggest that recent levels of perceived stress may influence the cortisol response to acute stress.

Stress-induced alterations in HPA-axis reactivity and mesolimbic reward activation in individuals with emotional eating

BACKGROUND

Emotional eating has emerged as a contributing factor to overeating, potentially leading to obesity or disordered eating behaviors. However, the underlying biological mechanisms related to emotional eating remain unclear. The present study examined emotional, hormonal, and neural alterations elicited by an acute laboratory stressor in individuals with and without emotional eating.

METHODS

Emotional (n = 13) and non-emotional eaters (n = 15) completed two main study visits, one week apart: one visit included a Stress version and the other a No-stress version of the Maastricht Acute Stress Task (MAST). Immediately pre- and post-MAST, blood was drawn for serum cortisol and participants rated their anxiety level. After the MAST, participants completed a Food Incentive Delay (FID) task during functional magnetic resonance imaging (fMRI), followed by an ad libitum snack period.

RESULTS

Emotional eaters exhibited elevated anxiety (p = 0.037) and cortisol (p = 0.001) in response to the Stress MAST. There were no changes in anxiety or cortisol among non-emotional eaters in response to the Stress MAST or in either group in response to the No-stress MAST. In response to the Stress MAST, emotional eaters exhibited reduced activation during anticipation of food reward in mesolimbic reward regions (caudate: p = 0.014, nucleus accumbens: p = 0.022, putamen: p = 0.013), compared to non-emotional eaters. Groups did not differ in snack consumption.

CONCLUSIONS

These data indicate disrupted neuroendocrine and neural responsivity to psychosocial stress amongst otherwise-healthy emotional eaters, who demonstrated hyperactive HPA-axis response coupled with hypoactivation in reward circuitry. Differential responsivity to stress may represent a risk factor in the development of maladaptive eating behaviors.

What's eating you? Risk factors for poor health behaviors among family caregivers

OBJECTIVES

Overeating and obesity are major public health issues in the United States. Caregivers are at greater risk of engaging in poor health behaviors, such as emotional eating, to cope with the demands of caregiving. Using Heatherton and Baumeister (1991) Escape Theory, this study examines the associations between caregiver characteristics (i.e. age, gender, and BMI) and emotional eating, including the extent to which family strain mediates these associations.

METHOD

Data are from the MIDUS 3 dataset (N = 326) and include family caregivers of older adults and children with special health care needs (Mage = 62.88 years, SD = 10.28; 69.6% female).

RESULTS

Female caregivers were more likely than male caregivers to engage in emotional eating. Age was significantly associated with emotional eating, where increased age was associated with less emotional eating. ANCOVA results indicated that obese caregivers were the most likely to engage in emotional eating. Results also indicated that family strain significantly mediated the association between caregiver age and emotional eating. Linear regression analyses indicated that female gender predicted emotional eating, although family strain did not mediate the association between gender and emotional eating. Similarly, after controlling for family strain as a mediator, higher BMI was still significantly associated with emotional eating, suggesting that BMI is a strong predictor of emotional eating among family caregivers regardless of present family strain.

CONCLUSION

Interventions targeted at managing family strain, particularly for younger, female caregivers, could improve coping and decrease poor health behaviors.

Perfectionism and Eating Behavior in the COVID-19 Pandemic

The novel coronavirus disease 2019 (COVID-19) represents a massive global health crisis leading to different reactions in people. Those reactions may be adaptive or not depending on situational or psychological processes. Disordered eating attitudes and behaviors are likely to be exacerbated by the pandemic through multiple pathways as suggested by Rodgers et al. (2020). Among the psychological variables that may have increased dysfunctional eating attitudes and behaviors as a consequence of the social distancing and isolation, we looked at perfectionism. Perfectionism is a well-recognized risk and maintaining factor of eating-related symptoms and interact with stress increasing the probability of dysfunctional reactions (e.g., Wang and Li, 2017). The present study investigated the relationship between multidimensional perfectionism and eating behaviors by considering the mediating role of psychological distress. Data were collected from two countries (Italy and Spain) by means of an online survey. The samples included 465 (63.4% female) participants from Italy and 352 (68.5% female) from Spain. Participants completed the short form of the Hewitt and Flett Multidimensional Perfectionism Scale (Lombardo et al., 2021) to assess self-oriented, other-oriented and socially prescribed perfectionism, as well as the short form of Three Factors Eating Questionnaire (Karlsson et al., 2000) and the Italian version of Depression Anxiety and Stress Scale-21 (Bottesi et al., 2015), respectively used to assess restrictive, emotional and uncontrolled eating on one hand, and depression, anxiety and stress on the other. Multigroup analysis was performed to test the hypothesized model. Results showed that other-oriented and socially prescribed perfectionism were indirectly related to most of the dysfunctional eating aspects through the mediation of psychological distress, and the pattern obtained was consistent in both countries. These findings evidence that the psychological distress potentially related to the COVID-19 disease mediates the negative impact of interpersonal perfectionism and the tendency to eat in response to negative emotions.

Multiple levels assessment of the RDoC "system for social process" in Eating Disorders: Biological, emotional and cognitive responses to the Trier Social Stress Test

BACKGROUND

Social dysfunction is a putative risk and maintaining factor for Eating Disorders (EDs). We assessed biological, emotional, and cognitive responses to a psychosocial stressor, in order to provide a multilevel investigation of the RDoC social process system in EDs.

METHODS

Patients were recruited among those seeking treatment for an ED. Cortisol response to Trier Social Stress Test (TSST) was measured in 105 subjects: 35 women with anorexia nervosa (AN), 32 with bulimia nervosa (BN) and 38 healthy women. Anxiety, hunger, and desire to eat throughout TSST were rated in a subgroup of them (23 AN, 21 BN, and 25 control women). Two-way ANOVAs with repeated measures were run to assess differences among groups.

RESULTS

The TSST-induced cortisol secretion of AN women was significantly higher than in BN and healthy women; this significance disappeared after controlling for body mass index. Compared to healthy women, both AN and BN women showed reduced cortisol reactivity that disappeared after controlling for trait anxiety and ineffectiveness. Both ED groups displayed increased anxiety response to TSST, while only AN group reported greater decreases in hunger and desire to eat. No significant correlations were found between cortisol and anxiety, hunger, or desire to eat in response to TSST.

CONCLUSIONS

People with EDs are characterized by blunted cortisol reactivity and greater anxiety, hunger, and desire to eat responses to a psychosocial stressor without any significant association between these measures. This study provides the first empirical and multilevel support to a deranged functioning of the RDoC "system for social process" in EDs.

Identifying stress-related eating in behavioural research: A review

Stress is a commonly reported precipitant of overeating. Understanding the relationship between stress and food intake is important, particularly in view of the increasing prevalence of obesity. The purpose of this review is to examine how stress-related eating has been defined and measured in the literature to date. There are no established diagnostic criteria or gold standards for quantification of stress-related eating. Questionnaires relying on the accuracy of self-report are the mainstay of identifying people who tend to eat in response to stress and emotions. There is a paucity of clinical research linking objective measurements of stress and appetite with self-reported eating behaviour. Limitations of the methodological approaches used and the heterogeneity between studies leave significant knowledge gaps in our understanding of the mechanism of stress related eating, and how best to identify it. These issues are discussed, and areas for further research are explored.

A systematic review of the Trier Social Stress Test methodology: Issues in promoting study comparison and replicable research

Since its development in 1993, the Trier Social Stress Test (TSST) has been used widely as a psychosocial stress paradigm to activate the sympathetic nervous system and hypothalamic-pituitary-adrenal axis (HPAA) stress systems, stimulating physiological functions (e.g. heart rate) and cortisol secretion. Several methodological variations introduced over the years have led the scientific community to question replication between studies. In this systematic review, we used the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) to synthesize procedure-related data available about the TSST protocol to highlight commonalities and differences across studies. We noted significant discrepancies across studies in how researchers applied the TSST protocol. In particular, we highlight variations in testing procedures (e.g., number of judges, initial number in the arithmetic task, time of the collected saliva samples for cortisol) and discuss possible misinterpretation in comparing findings from studies failing to control for variables or using a modified version from the original protocol. Further, we recommend that researchers use a standardized background questionnaire when using the TSST to identify factors that may influence physiological measurements in tandem with a summary of this review as a protocol guide. More systematic implementation and detailed reporting of TSST methodology will promote study replication, optimize comparison of findings, and foster an informed understanding of factors affecting responses to social stressors in healthy people and those with pathological conditions.

Neural Efficiency of Human-Robotic Feedback Modalities Under Stress Differs With Gender

Sensory feedback, which can be presented in different modalities - single and combined, aids task performance in human-robotic interaction (HRI). However, combining feedback modalities does not always lead to optimal performance. Indeed, it is not known how feedback modalities affect operator performance under stress. Furthermore, there is limited information on how feedback affects neural processes differently for males and females and under stress. This is a critical gap in the literature, particularly in the domain of surgical robotics, where surgeons are under challenging socio-technical environments that burden them physiologically. In the present study, we posited operator performance as the summation of task performance and neurophysiological cost of maintaining that performance. In a within-subject design, we used functional near-infrared spectroscopy to assess cerebral activations of 12 participants who underwent a 3D manipulation task within a virtual environment with concurrent feedback (visual and visual + haptic) in the presence and absence of a cognitive stressor. Cognitive stress was induced with the serial-7 subtraction test. We found that while task performance was higher with visual than visual + haptic feedback, it degraded under stress. The two feedback modalities were found to be associated with varying neural activities and neural efficiencies, and these were stress- and gender-dependent. Our findings engender further investigation into effectiveness of feedback modalities on males and females under stressful conditions in HRI.

Negative affect is associated with increased stress-eating for women with high perceived life stress

Perceived life stress (PLS) and cognitive restraint are associated with increased comfort food intake under stress and lead to weight gain and obesity, but the mechanisms by which they do so remain unclear. Stress and negative affect (NA) are associated with increased reward-driven comfort food intake as a means to 'feel better', particularly for individuals with higher PLS and cognitive restraint. Thus, we propose that PLS and cognitive restraint increase stress-eating by strengthening the relationship between stress-induced NA and comfort food intake. Upon comfort eating, individuals with higher PLS show greater reductions in the negative consequences of stress (e.g. NA). The rewarding effects of this 'emotional relief' may promote future stress-induced comfort eating, but this has yet to be examined. Thus, we investigate the pathways by which PLS or cognitive restraint increase snack intake under stress by proposing that 1) stress-induced NA is a stronger predictor of increased snack intake for women with greater PLS and cognitive restraint, and 2) greater PLS will be associated with greater reductions in NA upon snacking under stress (i.e. emotional relief). Forty-three healthy women were given snacks (chips, golden oreos, and M&Ms) to eat after a Trier Social Stress Test or rest period on separate days in counterbalanced order. Following linear regression analyses, we determined that stress-induced NA predicted more snack intake for women with higher PLS, and that higher PLS was associated with heightened emotional relief upon snacking under stress. Future studies are needed to directly assess whether greater emotional relief following stress-eating reinforces the learned association between stress-induced NA and intake, and ultimately explains greater stress-eating and obesity in women with higher PLS. This work may lead clinicians to focus on NA in the treatment of obesity-and stress-related illnesses for women with higher PLS.