Dysfunctional endogenous analgesia during exercise in patients with chronic pain: To exercise or not to exercise? (original) (raw)

Endogenous Pain Modulation in Response to Exercise in Patients with Rheumatoid Arthritis, Patients with Chronic Fatigue Syndrome and Comorbid Fibromyalgia, and Healthy Controls: A Double-Blind Randomized Controlled Trial

Pain Practice, 2014

Objective: Temporal summation (TS) of pain, conditioned pain modulation (CPM), and exercise-induced analgesia (EIA) are often investigated in chronic pain populations as an indicator for enhanced pain facilitation and impaired endogenous pain inhibition, respectively, but interactions are not yet clear both in healthy controls and in chronic pain patients. Therefore, the present double-blind randomized placebo-controlled study evaluates pains cores, TS, and CPM in response to exercise in healthy controls, patients with chronic fatigue syndrome and comorbid fibromyalgia (CFS/ FM), and patients with rheumatoid arthritis (RA), both under placebo and paracetamol condition. Methods: Fifty-three female volunteersof which 19 patients with CFS/FM, 16 patients with RA, and 18 healthy controlsunderwent a submaximal exercise test on a bicycle ergometer on 2 different occasions (paracetamol vs. placebo), with an interval of 7 days. Before and after exercise, participants rated pain intensity during TS and CPM.

Dysfunction of endogenous pain inhibition during exercise with painful muscles in patients with shoulder myalgia and fibromyalgia

PAIN, 2010

The aim of this study was to investigate how exercise influenced endogenous pain modulation in healthy controls, shoulder myalgia patients and fibromyalgia (FM) patients. Twenty-one healthy subjects, 20 shoulder myalgia patients and 20 FM patients, all females, participated. They performed standardized static contractions, that is, outward shoulder rotation (m. infraspinatus) and knee extension (m. quadriceps). Pressure pain thresholds (PPTs) were determined bilaterally at m. infraspinatus and m. quadriceps. During contractions PPTs were assessed at the contracting muscle, the resting homologous contralateral muscle and contralaterally at a distant site (m. infraspinatus during contraction of m. quadriceps and vice versa). Myalgia patients had lower PPTs compared to healthy controls at m. infraspinatus bilaterally (p < 0.01), but not at m. quadriceps. FM patients had lower PPTs at all sites compared to healthy controls (p < 0.001) and myalgia patients (p < 0.001). During contraction of m. infraspinatus PPTs increased compared to baseline at the end of contraction in healthy controls (all sites: p < 0.003), but not in myalgia or FM patients. During contraction of m. quadriceps PPTs increased compared to baseline at the end of contraction in healthy controls (all sites: p < 0.001) and myalgia patients (all sites: p < 0.02), but not in FM patients. In conclusion, we found a normal activation of endogenous pain regulatory mechanisms in myalgia patients during contraction of the non-afflicted m. quadriceps, but a lack of pain inhibition during contraction of the painful m. infraspinatus. FM patients failed to activate their pain inhibitory mechanisms during all contractions.

Musculoskeletal pain and exercise-challenging existing paradigms and introducing new

British journal of sports medicine, 2018

Traditional pain models that describe tissue pathology as a source of nocioceptive input directly linked with pain expression, have been insufficient for assessing and treating musculoskeletal pain. The need for pain to be avoided or alleviated as much as possible during physical activity has recently been challenged, with a paradigm shift from traditional biomedical models of pain towards a biopsychosocial model of pain.

Exercise, not to Exercise or how to Exercise in Patients with Chronic Pain? Applying Science to Practice

The Clinical Journal of Pain, 2014

Exercise is an AQ4 effective treatment strategy in various chronic musculoskeletal pain disorders, including chronic neck pain, osteoarthritis, headache, fibromyalgia, and chronic low back pain. Although exercise can benefit those with chronic pain, some patients (eg, those with fibromyalgia or chronic whiplash-associated disorders) encounter exercise as a pain-inducing stimulus and report symptom flares due to exercise. This paper focuses on benefits and detrimental effects of exercise in patients with chronic pain. It summarizes positive and negative effects of exercise therapy in migraine and tension-type headache and provides an overview of the scientific evidence of dysfunctional endogenous analgesia during exercise in patients with certain types of chronic pain. Further, the paper explains the relationship between exercise and recovery highlighting the need to address recovery strategies as well as exercise regimes during rehabilitation. The characteristics, demands, and strategies of adequate recovery to compensate stress from exercise and return to homeostatic balance will be described. Exercise is shown to be effective in the treatment of chronic tension-type headache and migraine. Aerobic exercise is the best option in migraine prophylaxis, whereas specific neck and shoulder exercises is a better choice in treating chronic tension-type headache. Besides the consensus that exercise therapy is beneficial in the treatment of chronic pain, the lack of endogenous analgesia in some chronic pain disorders should not be ignored. Furthermore, optimizing the balance between exercise and recovery is of crucial merit to avoid stress-related detrimental effects and achieve optimal functioning in patients with chronic pain.

The effects of a 15-week physical exercise intervention on pain modulation in fibromyalgia: Increased pain-related processing within the cortico-striatal- occipital networks, but no improvement of exercise-induced hypoalgesia

Neurobiology of Pain, 2023

Dysfunctional top-down pain modulation is a hallmark of fibromyalgia (FM) and physical exercise is a cornerstone in FM treatment. The aim of this study was to explore the effects of a 15-week intervention of strengthening exercises, twice per week, supervised by a physiotherapist, on exercise-induced hypoalgesia (EIH) and cerebral pain processing in FM patients and healthy controls (HC). FM patients (n = 59) and HC (n = 39) who completed the exercise intervention as part of a multicenter study were examined at baseline and following the intervention. Following the exercise intervention, FM patients reported a reduction of pain intensity, fibromyalgia severity and depression. Reduced EIH was seen in FM patients compared to HC at baseline and no improvement of EIH was seen following the 15-week resistance exercise intervention in either group. Furthermore, a subsample (Stockholm site: FM n = 18; HC n = 19) was also examined with functional magnetic resonance imaging (fMRI) during subjectively calibrated thumbnail pressure pain stimulations at baseline and following intervention. A significant main effect of exercise (post > pre) was observed both in FM patients and HC, in pain-related brain activation within left dorsolateral prefrontal cortex and caudate, as well as increased functional connectivity between caudate and occipital lobe bordering cerebellum (driven by the FM patients). In conclusion, the results indicate that 15-week resistance exercise affect pain-related processing within the cortico-striatal-occipital networks (involved in motor control and cognition), rather than directly influencing top-down descending pain inhibition. In alignment with this, exercise-induced hypoalgesia remained unaltered.

The effect of maximal exercise on temporal summation of second pain (windup) in patients with fibromyalgia syndrome

The Journal of Pain, 2001

Exercise activates endogenous opioid and adrenergic systems, but attenuation of experimental pain by exercise has not been shown consistently. In this study, effects of exercise on temporal summation of late pain responses to stimulation of unmyelinated (C) nociceptors were assessed. When a preheated thermode was applied repetitively to glabrous skin of the hand in a series of brief contacts at rates of 0.2 to 0.5 Hz, the perceived intensity of late thermal sensations increased after successive contacts. This summation of pain sensations provides information regarding the status of central opioid and N-methyl-D-aspartate receptor systems. For normal subjects, temporal summation of late pain sensations was substantially attenuated when testing began 1.5 or 10 minutes after exercise. Individuals diagnosed with fibromyalgia syndrome (FMS) report generalized chronic pain that is increased after exercise. Therefore, we hypothesized that strenuous exercise would increase summation of late pain sensations in this cohort. Patients with FMS and control subjects exerted to similarly high metabolic rates, as shown by physiologic monitoring. Ratings of late pain sensations increased for patients with FMS after exercise, an effect opposite to a decrease in ratings for age/sex-matched control subjects. In contrast to this result for experimentally induced pain, clinical pain ratings were not substantially altered after strenuous exercise by patients with FMS.

Exercise-induced pain threshold modulation in healthy subjects: a systematic review and meta-analysis

Principles and Practice of Clinical Research Journal

Background: The use of exercise is a potential treatment option to modulate pain (exercise-induced hypoalgesia). The pain threshold (PT) response is a measure of pain sensitivity that may be a useful marker to assess the effect of physical exercise on pain modulation. Aim: The aim of this systematic review and meta-analysis is to evaluate the PT response to exercise in healthy subjects. Methods: We searched in MEDLINE, EMBASE, Web of Science, Lilacs, and Scopus using a search strategy with the following search terms: "exercise" OR "physical activity" AND "Pain Threshold" from inception to December 2nd, 2019. As criteria for inclusion of appropriate studies: randomized controlled trials or quasi-experimental studies that enrolled healthy subjects; performed an exercise intervention; assessed PT. Hedge's effect sizes of PT response and their 95% confidence intervals were calculated, and random-effects meta-analyses were performed. Results: For the final analysis, thirty-six studies were included (n=1326). From this, we found a significant and homogenous increase in PT in healthy subjects (ES=0.19, 95% CI= 0.11 to 0.27, I2=7.5%). According to subgroup analysis, the effect was higher in studies: with women (ES=0.36); performing strength exercise (ES=0.34), and with moderate intensity (ES=0.27), and no differences by age were found. Confirmed by the meta-regression analysis. Conclusion: This meta-analysis provides evidence of small to moderate effects of exercise on PT in healthy subjects, being even higher for moderate strength exercise and in women. These results support the idea of modulation of the endogenous pain system due to exercise and highlight the need for clinical translation to the chronic pain population.