Impaired brachial artery endothelial function in young healthy women following an acute painful stimulus

Abstract

Impaired endothelial function has been observed during and immediately following an acutely painful stimulus. However, the extent to which this persists following pain dissipation is unclear. To determine whether painful ischemic handgrip exercise (pain task) causes impaired flow-mediated dilation (FMD) after the sensation of pain and hemodynamic responses have abated. A second purpose was to determine whether the response to pain differed with a predisposition to magnify, ruminate, and feel helpless about pain (pain catastrophizing status). Brachial artery FMD stimulated by reactive hyperemia was assessed via ultrasound in 18 (9 high catastrophizing) healthy, women (20 ± 1 years) before and 15 min after a 3 min pain task. The shear stress stimulus for FMD was estimated as shear rate (blood velocity/brachial artery diameter). RESULTS (MEAN ± SD): None of the variables were significantly impacted by pain catastrophizing status and are presented pooled across group. The pain task increased pain ratings [1 ± 1-6 ± 3 (0-10 scale) (p < 0.001)], mean arterial pressure (MAP) (p < 0.001) and heart rate (HR) (p < 0.001), all returning to pre-pain levels ≤2-min post-pain task (pre-pain vs. 2-min post-pain: pain rating p = 1.000; MAP p = 0.142; HR p = 0.992). The shear rate stimulus was not different between pre- and post-pain task FMD tests (p = 0.200). FMD decreased post-pain task (10.8 ± 4.6 vs. 7.0 ± 2.7 %, p < 0.001). These results indicate that, regardless of pain catastrophizing status, painful ischemic handgrip exercise has a deleterious impact on endothelial function that persists after the pain sensation and hemodynamic responses have abated.