Health Psychology, Faculty of Psychology and Educational Sciences.
Translational Research Center for Gastrointestinal Disorders (TARGID), Faculty of Medicine, University of Leuven, Leuven, Belgium.
Pain Med. 2018 Aug 1;19(8):1587-1596. doi: 10.1093/pm/pnx165.
Several chronic pain syndromes are characterized by deficient endogenous pain modulation as well as elevated negative affectivity and reduced resting heart rate variability. In order to elucidate the relationships between these characteristics, we investigated whether negative affectivity and heart rate variability are associated with endogenous pain modulation in a healthy population.
DESIGN, SUBJECTS, AND METHODS: An offset analgesia paradigm with noxious thermal stimulation calibrated to the individual's pain threshold was used to measure endogenous pain modulation magnitude in 63 healthy individuals. Pain ratings during constant noxious heat stimulation to the arm (15 seconds) were compared with ratings during noxious stimulation comprising a 1 °C rise and return of temperature to the initial level (offset trials, 15 seconds). Offset analgesia was defined as the reduction in pain following the 1 °C decrease relative to pain at the same time point during continuous heat stimulation.
Evidence for an offset analgesia effect could only be found when noxious stimulation intensity (and, hence, the individual's pain threshold) was intermediate (46 °C or 47 °C). Offset analgesia magnitude was also moderated by resting heart rate variability: a small but significant offset effect was found in participants with high but not low heart rate variability. Negative affectivity was not related to offset analgesia magnitude.
These results indicate that resting heart rate variability (HRV) is related to endogenous pain modulation (EPM) in a healthy population. Future research should focus on clarifying the causal relationship between HRV and EPM and chronic pain by using longitudinal study designs.
几种慢性疼痛综合征的特点是内源性疼痛调节不足，以及负性情感和静息心率变异性降低。为了阐明这些特征之间的关系，我们研究了在健康人群中，负性情感和心率变异性是否与内源性疼痛调节有关。
设计、对象和方法：使用一种无伤害性热刺激的偏置镇痛范式，该范式根据个体的疼痛阈值进行校准，以测量 63 名健康个体的内源性疼痛调节幅度。在手臂上进行恒定的伤害性热刺激（15 秒）期间的疼痛评分与在伤害性刺激包括 1°C 升高和温度回到初始水平的期间（偏置试验，15 秒）的评分进行比较。偏置镇痛定义为与连续热刺激相同时间点的疼痛相比，1°C 降低后的疼痛减轻。
只有当伤害性刺激强度（因此，个体的疼痛阈值）处于中等水平（46°C 或 47°C）时，才能发现偏置镇痛效应的证据。偏置镇痛幅度也受到静息心率变异性的调节：在心率变异性高但不低的参与者中，发现了一个小但显著的偏置效应。负性情感与偏置镇痛幅度无关。
这些结果表明，静息心率变异性（HRV）与健康人群中的内源性疼痛调节（EPM）有关。未来的研究应重点通过使用纵向研究设计，阐明 HRV 和 EPM 与慢性疼痛之间的因果关系。
