Tousignant-Laflamme Yannick, Marchand Serge
Faculty of Medicine and Health Sciences, School of Rehabilitation, Université de Sherbrooke, 3001, 12e avenue Nord, Sherbrooke, QC, J1H 5N4, Canada.
Clin Auton Res. 2009 Jun;19(3):167-73. doi: 10.1007/s10286-009-0004-7. Epub 2009 Mar 3.
We previously demonstrated that only men showed a significant correlation between heart rate (HR) and pain. Other authors also found sex differences in the autonomic and cardiovascular reactivity to pain, and sex hormones have been proposed to be partly responsible for these differences. However, no previous studies were done to examine if the autonomic and cardiovascular reactivity to pain vary across the menstrual cycle (MC).
Thirty-two healthy women were randomly tested 3 times across their MC (days 1-3, days 12-14 and days 19-23). The painful stimulus consisted of a 2 min cold pressor test (CPT) (immersion of the arm in cold noxious water at 12 degrees C). HR and blood pressure were recorded before and during the immersion using an ECG which also allowed us to measure heart rate variability (HRV).
Pain ratings during the CPT did not vary across the MC (P = 0.14). HRV (sympathetic and parasympathetic indicators) and blood pressure (systolic and diastolic) analysis showed that women had similar cardiovascular reactivity to pain throughout their MC. However, we found that the correlation between HR and pain ratings during the CPT varied across the MC, where there was a significant positive relationship between HR and pain (r = 0.36, P < 0.05) only during the menstrual phase.
These results add to our previous finding but tend to show that sex hormones have minimal influence on autonomic reactivity. Moreover, the great variability in intra- and inter-subject reactivity to pain does not allow us to predict the autonomic and cardiovascular reactivity to pain women will show throughout the MC.
我们之前证明只有男性的心率（HR）与疼痛之间存在显著相关性。其他作者也发现了自主神经和心血管对疼痛反应的性别差异，并且有人提出性激素是造成这些差异的部分原因。然而，之前没有研究探讨自主神经和心血管对疼痛的反应在月经周期（MC）中是否会发生变化。
32名健康女性在其月经周期内随机接受3次测试（第1 - 3天、第12 - 14天和第19 - 23天）。疼痛刺激包括2分钟的冷加压试验（CPT）（将手臂浸入12摄氏度的冷有害水中）。在浸入前和浸入过程中使用心电图记录心率和血压，该心电图还使我们能够测量心率变异性（HRV）。
CPT期间的疼痛评分在月经周期中没有变化（P = 0.14）。HRV（交感神经和副交感神经指标）和血压（收缩压和舒张压）分析表明，女性在整个月经周期中对疼痛的心血管反应相似。然而，我们发现CPT期间HR与疼痛评分之间的相关性在月经周期中有所不同，仅在月经期HR与疼痛之间存在显著正相关（r = 0.36，P < 0.05）。
这些结果补充了我们之前的发现，但倾向于表明性激素对自主神经反应的影响最小。此外，个体内和个体间对疼痛反应的巨大变异性使我们无法预测女性在整个月经周期中对疼痛的自主神经和心血管反应。
