Walking increases pain tolerance in humans: an experimental cross-over study

Abstract

Background and aims Exercise is commonly used as treatment for chronic pain with positive long-term effects on pain and pain-related disability. In pain-free subjects, hypoalgesia following an acute bout of exercise compared with a control condition has consistently been demonstrated also known as exercise-induced hypoalgesia (EIH). Walking exercise, a low intensity aerobic exercise, is frequently used in clinical practice as an easily applicable intervention for patients with chronic pain. Walking exercise is furthermore recommended as an effective treatment for patients with chronic musculoskeletal pain conditions to alleviate pain and reduce disability, however, the effect of walking on pain sensitivity is currently unknown. The aims of the present study were to investigate (1) the acute effect of walking on pain sensitivity, and (2) the relative (between-subjects) and absolute (within-subject) test-retest reliability of the hypoalgesic response across two sessions separated by 1 week. Methods In this randomised experimental cross-over study including two identical sessions, 35 pain-free subjects performed a standardized 6 min walking test and a duration-matched quiet rest condition in a randomized and counterbalanced order in each session. Before and after both conditions, handheld pressure pain thresholds (PPTs) were assessed at the thigh and shoulder, and pressure pain thresholds (cPPT) and pain tolerance (cPTT) were assessed with computer-controlled cuff algometry at the lower leg. Change in the pain sensitivity measures were analysed with repeated-measures ANOVAs, and test-retest reliability with intraclass correlation coefficients (ICC) and agreements in classification of EIH responders/non-responders between the two sessions. Results All subjects completed the walking conditions in both session 1 and session 2. The perceived intensity of walking assessed with rating of perceived exertion (RPE) and walking distance did not differ significantly between session 1 (distance: 632.5 ± 75.2 meters, RPE: 10.9 ± 1.9) and session 2 (distance: 642.1 ± 80.2 meters, RPE: 11.0 ± 2.4) (p > 0.11). Moreover, RPE showed excellent relative reliability with an ICC value of 0.95 [95%CI: 0.90–0.97]. Walking increased pain tolerance (mean difference: 2.6 kPa [95%CI: 0.5–4.9 kPa; p = 0.02]), but not pain thresholds compared with rest in both sessions. Hypoalgesia after walking demonstrated fair to good relative reliability (ICC = 0.61), however the agreement in classification of EIH responders/non-responders (absolute reliability) across sessions was low and not significant (κ = 0.19, p = 0.30). Conclusions Walking consistently increased pain tolerance but not pain thresholds compared with a duration-matched control condition with fair to good relative reliability between sessions. Based on classification of EIH responders/non-responders the absolute reliability between the two sessions was low indicating individual variance in the EIH response. Future studies should investigate the hypoalgesic effect of a walking exercise in a clinical pain population.

Impaired exercise‐induced hypoalgesia in individuals reporting an increase in low back pain during acute exercise

“…These participants demonstrated local and remote EIH suggesting that walking may serve as a beneficial non-pain provoking physical activity in most individuals with LBP. This is in line with Hviid et al (2019), who recently showed that walking induced hypoalgesia compared with a control condition in pain-free individuals. Higher cuff pain thresholds and lower clinical pain during the last 24 hr were associated with pain during walking suggesting that both pain sensitivity and clinical pain manifestations influence the sensitivity to physical activity.…”

Exercise-induced hypoalgesia after acute and regular exercise: experimental and clinical manifestations and possible mechanisms in individuals with and without pain

“… 80 In addition, low-intensity nonpainful aerobic and isometric exercises also increase the tolerance to a painful stimulus. A 20% increase in pain tolerance was observed by Vaegter et al 199 after a 3-minute submaximal isometric knee extension exercise, and after a 6-minute walking exercise 73 compared with rest in 35 pain-free individuals.…”

“…Despite robust hypoalgesia after exercise on a group level, the response to exercise is not identical across individuals and across days. Several studies have investigated the stability of the EIH response in pain-free individuals across different days using a number of aerobic 54 , 73 , 192 , 193 and isometric 200 exercise protocols. Across protocols, some individuals consistently show hypoalgesia after exercise, some individuals consistently showed hyperalgesia after exercise, and some individuals had a change in their response from hypoalgesic to hyperalgesic or vice versa between days.…”

Endogenous Modulation of Pain

“…the pain threshold), exercise also reduces more spinal and supraspinal mechanisms of pain. Vaegter and colleagues showed a significantly larger increase in pressure pain tolerance compared with the increase in pressure and heat pain thresholds after a 3 min submaximal isometric knee extension exercise [13] and after a 6 min walking condition [14], suggesting that coping with pain may be influenced to an even larger extent. Moreover, the degree of temporal summation of pain to repeated pressure and heat stimulations, which is suggested as a measure of excitability of the central nervous system, is reduced after one short session of isometric exercise [15,16].…”