The journal of pain : official journal of the American Pain Society
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Review Meta Analysis
A meta-analytic review of the hypoalgesic effects of exercise.
The purpose of this article was to examine the effects of acute exercise on pain perception in healthy adults and adults with chronic pain using meta-analytic techniques. Specifically, studies using a repeated measures design to examine the effect of acute isometric, aerobic, or dynamic resistance exercise on pain threshold and pain intensity measures were included in this meta-analysis. The results suggest that all 3 types of exercise reduce perception of experimentally induced pain in healthy participants, with effects ranging from small to large depending on pain induction method and exercise protocol. In healthy participants, the mean effect size for aerobic exercise was moderate (d(thr) = .41, d(int) = .59), while the mean effect sizes for isometric exercise (d(thr) = 1.02, d(int) = .72) and dynamic resistance exercise (d(thr) = .83, d(int) = .75) were large. In chronic pain populations, the magnitude and direction of the effect sizes were highly variable for aerobic and isometric exercise and appeared to depend on the chronic pain condition being studied as well as the intensity of the exercise. While trends could be identified, the optimal dose of exercise that is needed to produce hypoalgesia could not be systematically determined with the amount of data available. ⋯ This article presents a quantitative review of the exercise-induced hypoalgesia literature. This review raises several important questions that need to be addressed while also demonstrating that acute exercise has a hypoalgesic effect on experimentally induced pain in healthy adults, and both a hypoalgesic and hyperalgesic effect in adults with chronic pain.
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Randomized Controlled Trial
Effects of nicotine on spinal cord injury pain vary among subtypes of pain and smoking status: results from a randomized, controlled experiment.
Smoking has been associated with increased pain severity in general chronic pain populations. Less is known about the effects of smoking and nicotine on the multifaceted and often complex subtypes of pain that frequently occur following spinal cord injury (SCI). The purpose of this study was to examine the effects of nicotine on self-reported pain among individuals with SCI and to determine if the effect of nicotine varied by pain subtype. A randomized, placebo-controlled crossover design was used to determine the effect of nicotine exposure on subtypes of SCI-related pain among smokers and nonsmokers. A complex relationship emerged, such that the degree of reported pain with exposure to 2 mg of nicotine compared to placebo varied according to pain type and smoking status of the subject. Pain sites that had characteristics of both neuropathic and musculoskeletal symptoms (deemed complex neuropathic pain sites) exhibited pain reduction after nicotine exposure in nonsmokers. In sharp contrast, smokers with this form of pain exhibited an increase in pain severity. Data were also examined descriptively to determine potentially unique factors associated with complex neuropathic pain that may explain trends associated with clinically relevant changes following nicotine exposure. In sum, smoking or tobacco use history may determine the analgesic (or enhanced pain perception) effect of nicotine on post-SCI pain. ⋯ Pain characterized by both neuropathic and musculoskeletal symptoms decreased in severity after nicotine exposure in nonsmokers with SCI but increased in severity among smokers with SCI. The analgesic (or enhanced nociceptive) effect of nicotine may depend on tobacco use history.
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Study purposes were to determine the prevalence of persistent pain in the breast; characterize distinct persistent pain classes using growth mixture modeling; and evaluate for differences among these pain classes in demographic, preoperative, intraoperative, and postoperative characteristics. In addition, differences in the severity of common symptoms and quality of life outcomes measured prior to surgery, among the pain classes, were evaluated. Patients (n = 398) were recruited prior to surgery and followed for 6 months. Using growth mixture modeling, patients were classified into no (31.7%), mild (43.4%), moderate (13.3%), and severe (11.6%) pain groups based on ratings of worst breast pain. Differences in a number of demographic, preoperative, intraoperative, and postoperative characteristics differentiated among the pain classes. In addition, patients in the moderate and severe pain classes reported higher preoperative levels of depression, anxiety, and sleep disturbance than the no pain class. Findings suggest that approximately 25% of women experience significant and persistent levels of breast pain in the first 6 months following breast cancer surgery. ⋯ Persistent pain is a significant problem for 25% of women following surgery for breast cancer. Severe breast pain is associated with clinically meaningful decrements in functional status and quality of life.
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Randomized Controlled Trial
We discount the pain of others when pain has no medical explanation.
The present studies investigated the impact of medical and psychosocial information on the observer's estimations of pain, emotional responses, and behavioral tendencies toward another person in pain. Participants were recruited from the community (study 1: N = 39 women, 10 men; study 2: N = 41 women, 12 men) and viewed videos of 4 patients expressing pain, paired with vignettes describing absence or presence of 1) medical evidence for the pain and 2) psychosocial influences on the pain experience. A similar methodology was used for studies 1 and 2, except for the explicit manipulation of the presence/absence of psychosocial influences in study 2. For each patient video, participant estimations of each patient's pain and their own distress, sympathy, and inclination to help were assessed. In both studies, results indicated lower ratings on all measures when medical evidence for pain was absent. Overall, no effect of psychosocial influences was found, except in study 2 where participants indicated feeling less distress when psychosocial influences were present. The findings suggest that pain is taken less seriously when there is no medical evidence for the pain. The findings are discussed in terms of potential mechanisms underlying pain estimations as well as implications for caregiving behavior. ⋯ The present studies indicate that observers take the pain of others less seriously in the absence of clear medical evidence for the pain. These findings are important to further understand the social context in which pain for which there is no clear medical explanation is experienced.
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Previous studies have associated depression and temporomandibular joint disorders (TMDs). The temporality, however, remains to be clarified. Most patient studies have selected subjects from treatment facilities, whereas in epidemiological studies a clinical examination has not been performed. In this study the 5-year follow-up data of the population-based Study of Health in Pomerania (SHIP) were analyzed. To estimate the effect of symptoms of depression and those of anxiety on the risk of TMD pain, the Composite International Diagnostic-Screener (CID-S) and a clinical functional examination with palpation of the temporomandibular joint and the masticatory muscles were used. After exclusion of subjects having joint pain at baseline, a sample of 3,006 Caucasian participants with a mean age of 49 years resulted. Of those, 122 participants had signs of TMD joint pain upon palpation. Subjects with symptoms of depression had an increased risk of TMD joint pain upon palpation (rate ratio: 2.1; 95% confidence interval: 1.5-3.0; P < .001). Anxiety symptoms were associated with joint and with muscle pain. The diagnosis, prevention, and therapy of TMD pain should also consider symptoms of depression and those of anxiety, and appropriate therapies if necessary. ⋯ Depressive and anxiety symptoms should be considered as risk factors for TMD pain. Depressive symptoms are specific for joint pain whereas anxiety symptoms are specific for muscle pain, findings that deserve detailed examination. These findings may support decision-making in treating TMD.