The Result of Acute Induced Psychosocial Stress on Pain Sensitivity and Modulation in Healthy People.

Background Pain can be influenced by several factors, including stress. Stress can have various reactions on pain. These reactions are influenced by several internal factors such as gender, age, and experience with stress or pain. Objectives To determine the effect of acute stress on mechanical hyperalgesia (with pressure pain thresholds [PPT]), endogenous pain facilitation (measured by temporal summation [TS]), and inhibition (measured by conditioned pain modulation [CPM]) in healthy people and to determine which factors are responsible for this stress result. Study design Pre-posttest design. Setting Healthy volunteers from Belgium. Methods One hundred and one healthy pain-free patients underwent a modified Trier Social Stress Test. Prior and following the stress manipulation, PPT, TS, and CPM efficacy were determined in the mm. trapezius and quadriceps and overall. Furthermore, possible explanatory factors, such as fear of pain, pain catastrophizing, pain hypervigilance, and daily activity levels, were assessed using questionnaires. Results We found a significant stress result on widespread pain sensitivity, with an increase of PPT (P 0.05), and a decrease in CPM efficacy (P Limitations The efficacy of the stress manipulation was not examined, and the lack of a control group prevented to examine a real stress-effect. Furthermore, no physiologic parameters were measured as possibly influencing internal factors for the stress-result. Conclusions The increase in PPT was not a clinically significant change, whereas the decrease in CPM was meaningful. None of the factors predicted the stress result in all experimental pain measurements, and the predictions that were observed only explained a small proportion of the observed effects.