Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, United States.
Department of Psychiatry, Rush University, Chicago, IL, United States.
Pain. 2020 Dec;161(12):2887-2897. doi: 10.1097/j.pain.0000000000001969.
Aerobic exercise is believed to be an effective chronic low back pain (CLBP) intervention, although its mechanisms remain largely untested. This study evaluated whether endogenous opioid (EO) mechanisms contributed to the analgesic effects of an aerobic exercise intervention for CLBP. Individuals with CLBP were randomized to a 6-week, 18-session aerobic exercise intervention (n = 38) or usual activity control (n = 44). Before and after the intervention, participants underwent separate laboratory sessions to assess responses to evoked heat pain after receiving saline placebo or intravenous naloxone (opioid antagonist) in a double-blinded, crossover fashion. Chronic pain intensity and interference were assessed before and after the intervention. Endogenous opioid analgesia was indexed by naloxone-placebo condition differences in evoked pain responses (blockade effects). Relative to controls, exercise participants reported significantly greater pre-post intervention decreases in chronic pain intensity and interference (Ps < 0.04) and larger reductions in placebo condition evoked pain responsiveness (McGill Pain Questionnaire-Short Form [MPQ]-Total). At the group level, EO analgesia (MPQ-Total blockade effects) increased significantly pre-post intervention only among female exercisers (P = 0.03). Dose-response effects were suggested by a significant positive association in the exercise group between exercise intensity (based on meeting heart rate targets) and EO increases (MPQ-Present Pain Intensity; P = 0.04). Enhanced EO analgesia (MPQ-Total) was associated with a significantly greater improvement in average chronic pain intensity (P = 0.009). Aerobic exercise training in the absence of other interventions appears effective for CLBP management. Aerobic exercise-related enhancements in endogenous pain inhibition, in part EO-related, likely contribute to these benefits.
有氧运动被认为是一种有效的慢性下背痛（CLBP）干预措施，尽管其机制在很大程度上仍未得到验证。本研究评估了内源性阿片（EO）机制是否有助于 CLBP 的有氧运动干预的镇痛作用。CLBP 患者被随机分为 6 周 18 次有氧运动干预组（n = 38）或常规活动对照组（n = 44）。在干预前后，参与者分别进行了单独的实验室测试，以评估在双盲、交叉方式下接受生理盐水安慰剂或静脉内纳洛酮（阿片拮抗剂）后对诱发热痛的反应。在干预前后评估慢性疼痛强度和干扰。内源性阿片类药物镇痛作用通过纳洛酮-安慰剂条件下诱发疼痛反应的差异（阻断作用）来表示。与对照组相比，运动组报告的慢性疼痛强度和干扰的干预前后下降幅度明显更大（P < 0.04），且安慰剂条件下诱发疼痛反应的减少幅度更大（McGill 疼痛问卷-短表[MPQ]-总）。在群体水平上，仅在女性运动者中，EO 镇痛（MPQ-总阻断作用）在干预前后显著增加（P = 0.03）。运动组中运动强度（基于达到心率目标）与 EO 增加（MPQ-现在疼痛强度）之间存在显著正相关，提示存在剂量反应效应（P = 0.04）。增强的 EO 镇痛（MPQ-总）与平均慢性疼痛强度的显著改善相关（P = 0.009）。在没有其他干预措施的情况下进行有氧运动训练似乎对 CLBP 的管理有效。与有氧运动相关的内源性疼痛抑制增强，部分与 EO 相关，可能有助于这些益处。
