Associations Between Activity And Exercise-Induced Changes In Endocannabinoids In Adults With Chronic Low Back Pain
Bibliographic record
Abstract
Exercise-induced hypoalgesia (EIH) is a decrease in pain post-exercise, which can be moderated by activity level and may be related to changes in endocannabinoids (eCBs). Individuals with chronic low back pain (CLBP) may not experience EIH. PURPOSE The purpose of this study was to explore associations between objective assessments of activity (i.e., sedentary time, steps, and moderate-to-vigorous physical activity [MVPA]) and changes in eCBs (i.e., 2AG and AEA) and pain in individuals with CLBP. METHODS 40 participants with CLBP and 20 age/sex matched-pain free adults (PF) wore an activPAL3 accelerometer for 7 days. Participants then completed the McGill Pain Questionnaire (MPQ) and had their blood drawn prior to and following a 30-minute moderate intensity exercise session on a cycle ergometer. From the activPAL, objective assessments of activity were obtained. Levels of circulating eCBs were quantified in serum. Total scores from the MPQ were used to assess perceived pain. To assess exercise response, change scores for AEA, 2AG, and pain were used. Pearson correlations explored associations between sitting time, steps, and MVPA, with changes in AEA, 2AG, and MPQ for both PF and CLBP. RESULTS Correlations between activity level and MPQ scores were non-significant for CLBP (r = -0.07 to 0.02, p > 0.05) and PF (r = -0.07 to 0.13, p > 0.05). Correlations between activity level and eCB exercise response were non-significant for those with CBLP (r = -0.17 to 0.14, p > 0.05). In PF, there were strong and moderate positive correlations between MVPA and changes in 2AG (r = 0.66) and AEA (r = 0.31), respectively, a moderate positive correlation between steps and changes in 2AG (r = 0.44), and a strong negative correlation between sitting time and changes in 2AG (r = -0.56). CONCLUSION Activity levels of those with CLBP did not appear related to eCB changes with exercise. For PF individuals, higher activity levels and lower sitting time were significantly correlated with the exercise-induced changes of eCBs (2AG and AEA). This shows that eCB release in response to exercise may be influenced by physical activity and sitting time in the general population (PF individuals), but not in those with CLBP. Further understanding of how pain may interfere with natural eCB activity in response to exercise in chronic pain populations appears warranted.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".