Broadening the Scope of Resilience in Chronic Pain: Methods, Social Context, and Development.

PURPOSE OF REVIEW: A wellspring of new research has offered varying models of resilience in chronic pain populations; however, resilience is a multifaceted and occasionally nebulous construct. The current review explores definitional and methodological issues in existing observational and clinical studies and offers new directions for future studies of pain resilience. RECENT FINDINGS: Definitions of pain resilience have historically relied heavily upon self-report and from relatively narrow scientific domains (e.g., positive psychology) and in narrow demographic groups (i.e., Caucasian, affluent, or highly educated adults). Meta-analytic and systematic reviews have noted moderate overall quality of resilience-focused assessment and treatment in chronic pain, which may be attributable to these narrow definitions. Integration of research from affiliated fields (developmental models, neuroimaging, research on historically underrepresented groups, trauma psychology) has the potential to enrich current models of pain resilience and ultimately improve the empirical and clinical utility of resilience models in chronic pain.

Initial validation of the 12-item Tampa Scale of Kinesiophobia in a retrospective sample of adults with chronic headache.

INTRODUCTION: An area of emerging interest in chronic pain populations concerns fear of pain and associated fear of movement (kinesiophobia)-a cognitive appraisal pattern that is well-validated in non-headache chronic pain. However, there is limited research on whether this construct can be measured in a similar manner in headache populations. METHODS: The current project details a confirmatory factor analysis of the 12-Item Tampa Scale of Kinesiophobia (TSK-12) using a clinical data set from 210 adults with diverse headache diagnoses presenting for care at a multidisciplinary pain clinic. One item (concerning an "accident" that initiated the pain condition) was excluded from analysis. RESULTS: Results of the confirmatory factor analysis for the remaining 12 items indicated adequate model fit for the previously established 2-factor structure (activity avoidance and bodily harm/somatic focus subscales). In line with previous literature, total TSK-12 scores showed moderate correlations with pain severity, pain-related interference, positive and negative affect, depressive and anxious symptoms, and pain catastrophizing. DISCUSSION: The current study is the first to examine the factor structure of the TSK-12 in an adult headache population. The results support the relevance of pain-related fear to the functional and psychosocial status of adults with chronic headache, although model fit of the TSK-12 could be characterized as adequate rather than optimal. Limitations of the study include heterogeneity in headache diagnosis and rates of comorbid non-headache chronic pain in the sample. Future studies should replicate these findings in more homogenous headache groups (eg, chronic migraine) and examine associations with behavioral indices and treatment response.

Characterization of chronic overlapping pain conditions in patients with chronic migraine: A CHOIR study.

OBJECTIVE: Chronic overlapping pain conditions (COPCs) represent a co-aggregation of widespread pain disorders. We characterized differences in physical and psychosocial functioning in patients with chronic migraine (CM) and those with CM and COPCs. BACKGROUND: Patients with CM and COPCs have been identified as a distinct subgroup of patients with CM, and these patients may be vulnerable to greater symptom severity and burden. METHODS: Data were extracted from Collaborative Health Outcomes Information Registry (an open-source learning health-care system), completed at the patients' first visit at a large tertiary care pain management center and electronic medical records. In 1601 patients with CM, the number of non-cephalic areas of pain endorsed on a body map was used to examine the differences in pain, physical and psychosocial function, adverse life experience, and health-care utilization. RESULTS: Patients endorsing more body map regions reported significantly worse symptoms and function across all domains. Scored on a t-score metric (mean = 50, SD = 10), endorsement of one additional body map region corresponded with a 0.69-point increase in pain interference (95% CI = 0.55, 0.82; p < 0.001; Cohen's f = 0.328), 1.15-point increase in fatigue (95% CI = 0.97, 1.32; p < 0.001; Cohen's f = 0.432), and 1.21-point decrease in physical function (95% CI = -1.39, -1.03; p < 0.001; Cohen's f = 0.560). Patients with more widespread pain reported approximately 5% more physician visits (95% CI = 0.03, 0.07; p < 0.001), and patients reporting adverse life events prior to age 17 endorsed 22% more body map regions (95% CI = 0.11, 0.32; p < 0.001). CONCLUSIONS: Patients with CM and other overlapping pain conditions as noted on the body map report significantly worse pain-related physical function, psychosocial functioning, increased health-care utilization, and greater association with adverse life experiences, compared with those with localized CM. This study provides further evidence that patients with CM and co-occurring pain conditions are a distinct subgroup of CM and can be easily identified through patient-reported outcome measures.

Perceived Injustice Mediates the Relationship Between Perceived Childhood Neglect and Current Function in Patients with Chronic Pain: A Preliminary Pilot Study.

Cumulative evidence supports the association between perceived childhood neglect and adulthood psychological and physical health. To date, pathways mediating this association remain largely unknown, though other evidence suggests that negative patterns of appraisal, including injustice perception related to pain, may be shaped by prior adverse social experiences. Consequently, the current study examined perceived injustice about chronic pain as a possible factor connecting childhood neglect and pain-related outcomes, given its relevance for both adaptation to chronic pain and to prior adverse life experiences. Patients (n = 742) visiting a tertiary pain clinic completed a survey administered via the Collaborative Health Outcomes Information Registry. Path modeling analyses were used to examine perceived injustice as a mediator of the relationships between childhood neglect and affective distress and physical function, after controlling for pain intensity and pain catastrophizing. Patients endorsing childhood neglect reported higher levels of perceived injustice and worse affective distress and physical function. Further, inclusion of perceived injustice as a mediator fully accounted for the relationship between neglect and current levels of physical function, and accounted for a significant proportion of the relationship between neglect and current levels of affective distress. These preliminary findings suggest that perceived injustice appears to be a more proximal factor by which prior experiences of neglect may adversely affect adaptation to chronic pain. Given the single-item assessment of childhood neglect and cross-sectional nature of the current findings, further research may focus on replicating these findings in longitudinal studies with validated measures and examining other adverse social experiences (e.g., abuse, social disparities) that may contribute to injustice perception and poor pain-related outcomes.

Outcomes in Long-term Opioid Tapering and Buprenorphine Transition: A Retrospective Clinical Data Analysis.

BACKGROUND: There are significant medical risks of long-term opioid therapy (LTOT) for chronic pain. Consequently, there is a need to identify effective interventions for the reduction of high-dose full-agonist opioid medication use. METHODS: The current study details a retrospective review of 240 patients with chronic pain and LTOT presenting for treatment at a specialty opioid refill clinic. Patients first were initiated on an outpatient taper or, if taper was not tolerated, transitioned to buprenorphine. This study analyzes potential predictors of successful tapering, successful buprenorphine transition, or failure to complete either intervention and the effects of this clinical approach on pain intensity scores. RESULTS: One hundred seven patients (44.6%) successfully tapered their opioid medications under the Centers for Disease Control and Prevention guideline target dose (90 mg morphine-equianalgesic dosage), 45 patients (18.8%) were successfully transitioned to buprenorphine, and 88 patients (36.6%) dropped out of treatment: 11 patients during taper, eight during buprenorphine transition, and 69 before initiating either treatment. Conclusions. Higher initial doses of opioids predicted a higher likelihood of requiring buprenorphine transition, and a co-occurring benzodiazepine or z-drug prescription predicted a greater likelihood of dropout from both interventions. Patterns of change in pain intensity according to treatment were mixed: among successfully tapered patients, 52.8% reported greater pain and 23.6% reported reduced pain, whereas 41.8% reported increased pain intensity and 48.8% reported decreased pain after buprenorphine transition. Further research is needed on predictors of treatment retention and dropout, as well as factors that may mitigate elevated pain scores after reduction of opioid dosing.

Clinical Profiles of Concurrent Cannabis Use in Chronic Pain: A CHOIR Study.

OBJECTIVE: Despite evidence of the analgesic benefits of cannabis, there remains a relative scarcity of research on the short- and long-term effects of cannabis use in individuals with chronic pain. DESIGN: The current study is a secondary analysis of clinical data from the Collaborative Health Outcomes Information Registry (CHOIR). SETTING: Data were drawn from a cohort of patients of a multidisciplinary tertiary care pain clinic. SUBJECTS: The study sample consisted of data from 7,026 new patient visits from CHOIR; of these, 1,668 patients with a follow-up time point within 180 days were included in a longitudinal analysis. METHODS: Clinical data were analyzed to characterize cross-sectional differences in pain and indicators of psychological and physical function according to self-reported, concurrent cannabis use. Additionally, a propensity score-weighted longitudinal analysis was conducted, examining cannabis use as a predictor of changes in clinical variables across time. RESULTS: Cross-sectional analyses suggested significantly poorer sleep and significantly higher intensities of pain, emotional distress, and physical and social dysfunction in patients reporting ongoing cannabis use; however, these differences were relatively small in magnitude. However, no differences between cannabis users and nonusers in terms of longitudinal changes in clinical variables were noted. DISCUSSION: Our results are among the first to examine concurrent cannabis use as a prognostic variable regarding trajectories of pain-related variables in tertiary care. Future studies may benefit from examining the effect of cannabis initiation, concurrent medication use, and specific aspects of cannabis use (dose, duration of use, or cannabis type) on clinical outcomes.

Negative Affect-Related Factors Have the Strongest Association with Prescription Opioid Misuse in a Cross-Sectional Cohort of Patients with Chronic Pain.

OBJECTIVE: Increased opioid prescription to relieve pain among patients with chronic pain is associated with increased risk for misuse, potentially leading to substance use disorders and overdose death. We aimed to characterize the relative importance and identify the most significant of several potential risk factors for the severity of self-reported prescribed opioid misuse behaviors. METHODS: A sample of 1,193 patients (mean age ± SD = 50.72 ± 14.97 years, 64.04% female) with various chronic pain conditions completed a multidimensional registry assessing four pain severity measures and 14 physical, mental, and social health status factors using the National Institutes of Health's Patient-Reported Outcomes Measurement Information System (PROMIS). A validated PROMIS measure of medication misuse was completed by 692 patients who endorsed currently taking opioid medication. Patients taking opioid medications were compared across all measures with those who do not take opioid medications. Subsequently, a data-driven regression analysis was used to determine which measures best explained variability in severity of misuse. We hypothesized that negative affect-related factors, namely anxiety, anger, and/or depression, would be key predictors of misuse severity due to their crucial role in chronic pain and substance use disorders. RESULTS: Patients taking opioid medications had significantly greater impairment across most measures. Above and beyond demographic variables, the only and most significant predictors of prescribed opioid misuse severity were as follows: anxiety (ß = 0.15, P = 0.01), anger (ß = 0.13, P = 0.02), Pain Intensity-worst (ß = 0.09, P = 0.02), and depression (ß = 0.13, P = 0.04). CONCLUSIONS: Findings suggest that anxiety, anger, and depression are key factors associated with prescribed opioid misuse tendencies in patients with chronic pain and that they are potential targets for therapeutic intervention.

The Impact of Social Isolation on Pain Interference: A Longitudinal Study.

Background: Evidence suggests social interactions play an important role in pain perception. Purpose: The aim of this study was to determine whether social isolation (SI) in people with persistent pain determines pain interference (PI) and physical function over time. Methods: Patients seeking care at a tertiary pain management referral center were administered the Patient Reported Outcome Measurement Information System (PROMIS®) SI, PI, physical function, depression, and average pain intensity item banks at their initial consultation and subsequent visits as part of their routine clinical care. We used a post hoc simulation of an experiment using propensity score matching (n = 4,950) and carried out a cross-lagged longitudinal analysis (n = 312) of retrospective observational data. Results: Cross-lagged longitudinal analysis showed that SI predicted PI at the next time point, above and beyond the effects of pain intensity and covariates, but not vice versa. Conclusions: These data support the importance of SI as a factor in pain-related appraisal and coping and demonstrate that a comprehensive assessment of the individuals' social context can provide a better understanding of the differential trajectories for a person living with pain. Our study provides evidence that the impact of pain is reduced in individuals who perceive a greater sense of inclusion from and engagement with others. This study enhances the understanding of how social factors affect pain and have implications for how the effectiveness of therapeutic interventions may be improved. Therapeutic interventions aimed at increasing social connection hold merit in reducing the impact of pain on engagement with activities.

Associations of Pain Intensity and Frequency With Loneliness, Hostility, and Social Functioning: Cross-Sectional, Longitudinal, and Within-Person Relationships.

BACKGROUND: The current studies investigated associations between pain intensity and pain frequency with loneliness, hostility, and social functioning using cross-sectional, longitudinal, and within-person data from community-dwelling adults with varying levels of pain. METHOD: Secondary analysis of preexisting data was conducted. Study 1 investigated cross-sectional (baseline data: n = 741) and longitudinal (follow-up data: n = 549, observed range between baseline and follow-up: 6-53 months) associations. Study 2 tested within-person associations using daily diaries across 30 days from a subset of the participants in Study 1 (n = 69). RESULTS: Cross-sectionally, pain intensity and frequency were associated with higher loneliness (ßintensity = 0.16, ßfrequency = 0.17) and worse social functioning (ßintensity = - 0.40, ßfrequency = - 0.34). Intensity was also associated with higher hostility (ß = 0.11). Longitudinally, pain intensity at baseline predicted hostility (ß = 0.19) and social functioning (ß = - 0.20) at follow-up, whereas pain frequency only predicted social functioning (ß = - 0.21). Within people, participants reported higher hostility (γ = 0.002) and worse social functioning (γ = - 0.013) on days with higher pain, and a significant average pain by daily pain interaction was found for loneliness. Pain intensity did not predict social well-being variables on the following day. CONCLUSION: Pain intensity and frequency were associated with social well-being, although the effects were dependent on the social well-being outcome and the time course being examined.

Sharing Positive Experiences Boosts Resilient Thinking: Everyday Benefits of Social Connection and Positive Emotion in a Community Sample.

The influence of shared enjoyment and positive affect (PA) on resilient thinking was examined in 191 middle-aged adults (40-65 years), participating in a study of resilience. Participants completed diaries assessing positive events, shared enjoyment, PA, and resilient cognitions (RC). Multilevel structural equation modeling was utilized to examine when and who engages in RC. Participants reported more RC on days they experienced more positive experiences. This relationship was explained by shared enjoyment and PA. Level-1 proportional reduction of variance (PRV) for shared enjoyment, PA, and RC was 9%, 10%, and 35%, respectively. Individuals reporting more positive experiences trended toward a more resilient mindset; PA accounted for this relationship. Shared enjoyment mediated the relationship between interpersonal events and PA. These findings suggest PA is integral to having a resilient mindset, and shared enjoyment is a potential mechanism that may influence PA. Level-2 PRV for shared enjoyment, PA, and RC was 22%, 21%, and 55%, respectively. RC were associated with less depression and anxiety; and greater well-being, vitality, and physical functioning at follow-up.

Predictors of Daily Pain Medication Use in Individuals with Recurrent Back Pain.

PURPOSE: A key component to chronic pain management regimens is the use of analgesic medications. Psychological factors, such as mood states, may also affect the use of pain medications for individuals with chronic pain, but few observational studies have examined how these factors may predict pain medication use at the daily level. METHODS: Daily assessments from 104 individuals with back pain were used to examine fluctuations in daily pain intensity, mood, sleep quality, and physical activity as predictors of the likelihood of pain medication (opioid and non-opioid) use and levels of medication use on the same day. RESULTS: Pain intensity and mood ratings significantly predicted whether participants used pain medication on the same day, while only pain intensity predicted whether participants used more medication than usual. Further, current opioid users were more likely to increase the amount of their medication use on days of higher pain. DISCUSSION: This article identifies fluctuations in daily pain intensity and mood as salient predictors of daily pain medication use in individuals with recurrent back pain. The current study is among the first to highlight both pain and mood states as predictors of daily pain medication use in individuals with back pain, though future studies may expand on these findings through the use of higher-resolution daily medication use variables.

Pain Catastrophizing Moderates Relationships between Pain Intensity and Opioid Prescription: Nonlinear Sex Differences Revealed Using a Learning Health System.

BACKGROUND: Pain catastrophizing is a maladaptive response to pain that amplifies chronic pain intensity and distress. Few studies have examined how pain catastrophizing relates to opioid prescription in outpatients with chronic pain. METHODS: The authors conducted a retrospective observational study of the relationships between opioid prescription, pain intensity, and pain catastrophizing in 1,794 adults (1,129 women; 63%) presenting for new evaluation at a large tertiary care pain treatment center. Data were sourced primarily from an open-source, learning health system and pain registry and secondarily from manual review of electronic medical records. A binary opioid prescription variable (yes/no) constituted the dependent variable; independent variables were age, sex, pain intensity, pain catastrophizing, depression, and anxiety. RESULTS: Most patients were prescribed at least one opioid medication (57%; n = 1,020). A significant interaction and main effects of pain intensity and pain catastrophizing on opioid prescription were noted (P < 0.04). Additive modeling revealed sex differences in the relationship between pain catastrophizing, pain intensity, and opioid prescription, such that opioid prescription became more common at lower levels of pain catastrophizing for women than for men. CONCLUSIONS: Results supported the conclusion that pain catastrophizing and sex moderate the relationship between pain intensity and opioid prescription. Although men and women patients had similar Pain Catastrophizing Scale scores, historically "subthreshold" levels of pain catastrophizing were significantly associated with opioid prescription only for women patients. These findings suggest that pain intensity and catastrophizing contribute to different patterns of opioid prescription for men and women patients, highlighting a potential need for examination and intervention in future studies.

Pain catastrophizing mediates the relationship between trait happiness and depressive symptoms in individuals with current pain.

OBJECTIVE: There is an extensive relationship between chronic pain and depression; however, there is less research examining whether pain-specific factors, such as pain intensity, predict depression, above and beyond the role of normative factors, such as positive emotions. The current study characterized the independent contributions of pain intensity, pain catastrophizing, and a trait measure of happiness to self-rated depressive symptoms. METHODS: We recruited and enrolled 70 volunteers across 3 groups of participants: two groups of patients with current low back pain (one group on opioids and one group opioid-naïve), and individuals in a methadone maintenance treatment program. RESULTS: Of note, participants reporting concurrent opioid use reported significantly higher levels of depressive symptomatology, although study groups did not differ on any other clinical variables. In our path model, we failed to find direct relationships between pain (intensity or duration) and either trait happiness or depressive symptoms (p > .05). However, our analysis did reveal that individuals with chronic back pain who reported higher levels of trait happiness reported lower levels of depressive symptomatology; this effect was significantly mediated by lower levels of pain catastrophizing (standardized ab = -.144, p = .002). CONCLUSION: Our analysis suggests that trait happiness, while unrelated to ongoing pain, may predict a decreased vulnerability to depressive symptoms in individuals with chronic pain, which may operate via lower levels of pain catastrophizing.

The Psychosocial Context of Financial Stress: Implications for Inflammation and Psychological Health.

OBJECTIVE: Psychological distress may contribute to chronic activation of acute-phase inflammation. The current study investigated how financial stressors influence psychosocial functioning and inflammation. This study examined a) the direct relations between financial stress and inflammation; b) whether the relationships between financial stress and inflammation are mediated in part by negative interpersonal events, psychological distress, and psychological well-being; and c) whether social standing in one's community moderates the relations between financial stress and psychological distress, psychological well-being, and markers of inflammation (interleukin-6 [IL-6] and C-reactive protein). METHODS: Stressful financial and interpersonal events over the previous year, perceived social status, indices of psychological well-being and distress, and levels of IL-6 and C-reactive protein were assessed in a community sample of 680 middle-aged adults (ages 40-65 years). RESULTS: Structural equation modeling analyses revealed significant relations among financial stress, interpersonal stress, and psychological distress and well-being, and complex relationships between these variables and inflammatory markers. Psychological well-being mediated the association between financial stress and IL-6 ([mediation] ab = 0.012, standard error [SE] = 0.006, p = .048). Furthermore, individuals with higher perceived social standing within their communities exhibited a stronger relation between negative financial events and both interpersonal stressors (interaction B = 0.067, SE = 0.017, p < .001) and C-reactive protein (interaction B = 0.051, SE = 0.026, p = .050). CONCLUSIONS: Financial stress demonstrates complex relations with inflammation, due partly to psychological well-being and social perceptions. Findings are discussed with regard to the social context of stress and physiological factors pertinent to stress adaptation and inflammation.

Social Disruption Mediates the Relationship Between Perceived Injustice and Anger in Chronic Pain: a Collaborative Health Outcomes Information Registry Study.

BACKGROUND: Perceptions of pain as unfair are a significant risk factor for poorer physical and psychological outcomes in acute injury and chronic pain. Chief among the negative emotions associated with perceived injustice is anger, arising through frustration of personal goals and unmet expectations regarding others' behavior. However, despite a theoretical connection with anger, the social mediators of perceived injustice have not been demonstrated in chronic pain. PURPOSE: The current study examined two socially based variables and a broader measure of pain interference as mediators of the relationships between perceived injustice and both anger and pain intensity in a sample of 302 patients in a tertiary care pain clinic setting. METHODS: Data from the Collaborative Health Outcomes Information Registry (CHOIR) were analyzed using cross-sectional path modeling analyses to examine social isolation, satisfaction with social roles and activities, and pain-related interference as potential mediators of the relationships between perceived injustice and both anger and pain intensity. RESULTS: When modeled simultaneously, ratings of social isolation mediated the relationship between perceived injustice and anger, while pain-related interference and social satisfaction did not. Neither social variable was found to mediate the relationship between perceived injustice and pain intensity, however. CONCLUSIONS: The current findings highlight the strongly interpersonal nature of perceived injustice and anger in chronic pain, though these effects do not appear to extend to the intensity of pain itself. Nevertheless, the results highlight the need for interventions that ameliorate both maladaptive cognitive appraisal of pain and pain-related disruptions in social relationships.

Development of the Sensory Hypersensitivity Scale (SHS): a self-report tool for assessing sensitivity to sensory stimuli.

Sensory hypersensitivity is one manifestation of the central sensitization that may underlie conditions such as fibromyalgia and chronic fatigue syndrome. We conducted five studies designed to develop and validate the Sensory Hypersensitive Scale (SHS); a 25-item self-report measure of sensory hypersensitivity. The SHS assesses both general sensitivity and modality-specific sensitivity (e.g. touch, taste, and hearing). 1202 participants (157 individuals with chronic pain) completed the SHS, which demonstrated an adequate overall internal reliability (Cronbach's alpha) of 0.81, suggesting the tool can be used as a cross-modality assessment of sensitivity. SHS scores demonstrated only modest correlations (Pearson's r) with depressive symptoms (0.19) and anxiety (0.28), suggesting a low level of overlap with psychiatric complaints. Overall SHS scores showed significant but relatively modest correlations (Pearson's r) with three measures of sensory testing: cold pain tolerance (-0.34); heat pain tolerance (-0.285); heat pain threshold (-0.271). Women reported significantly higher scores on the SHS than did men, although gender-based differences were small. In a chronic pain sample, individuals with fibromyalgia syndrome demonstrated significantly higher SHS scores than did individuals with osteoarthritis or back pain. The SHS appears suitable as a screening measure for sensory hypersensitivity, though additional research is warranted to determine its suitability as a proxy for central sensitization.

Nonlinear Effects of Noxious Thermal Stimulation and Working Memory Demands on Subjective Pain Perception.

OBJECTIVE: A bidirectional relationship between working memory (WM) and acute pain has long been assumed, but equivocal evidence exists regarding this relationship. This study characterized the relationship between WM and acute pain processing in healthy individuals using an adapted Sternberg WM task. DESIGN: Participants completed a Sternberg task while receiving noxious thermal stimulation. Participants received a pseudorandom presentation of four different temperatures (baseline temperatures and individually determined low-, medium-, and high-temperature stimuli) and four levels of Sternberg task difficulty (0-, 3-, 6-, and 9-letter strings). SUBJECTS: Twenty-eight healthy participants were recruited from Stanford University and the surrounding community to complete this study. RESULTS: A nonlinear interaction between intensity of thermal stimulation and difficulty of the Sternberg task was noted. Increased cognitive load from the Sternberg task resulted in increased perception of pain in low-intensity thermal stimulation but suppressed pain perception in high-intensity thermal stimulation. Thermal stimulation had no significant effect on participants' response time or accuracy on the Sternberg task regardless of intensity level. CONCLUSIONS: Pain perception appears to decrease as a function of WM load only for sufficiently noxious stimuli. However, increasing noxious stimuli did not affect cognitive performance. These complex relationships may reflect a shared cognitive space that can become "overloaded" with input of multiple stimuli of sufficient intensity.

Respiratory sinus arrhythmia: a marker of resilience to pain induction.

BACKGROUND: There may be significant individual differences in physiological regulatory responses to the experience of pain and stress. Respiratory sinus arrhythmia is a physiological indicator that may have implications for efficient physiological responses to pain and stress. PURPOSE: Fatigue is an indicator of inefficient self-regulation under stressful conditions. The current study examined processes that impact changes in fatigue in response to pain. METHODS: Fifty-nine women (33 with fibromyalgia and 26 healthy controls) were exposed to repeated thermal pain stimuli and were asked to rate their feelings of fatigue after each block of thermal pain exposures. RESULTS: Self-reported fatigue affect increased during pain induction, but greater respiratory sinus arrhythmia predicted less-pronounced increases in fatigue affect across induction trials. CONCLUSIONS: Respiratory sinus arrhythmia appears to be a promising indicator of physiological resilience to pain, predicting an attenuated effect of repeated pain exposure on self-reported fatigue. Implications of efficient regulation of pain, fatigue, and long-term physical health are discussed.