Effects of Acute Experimental Stress on Pain Sensitivity and Cortisol Levels in Healthy Participants: A Randomized Crossover Pilot Study

Aims: To investigate pain sensitivity in the masseter muscle and index finger in response to acute psychologic stress in healthy participants. Methods: Fifteen healthy women (23.7 ± 2.3 years) participated in two randomized sessions: in the experimental stress session, the Paced Auditory Serial Addition Task (PASAT) was used to induce acute stress, and in the control session, a control task was performed. Salivary cortisol, perceived stress levels, electrical and pressure pain thresholds (PTs), and pain tolerance levels (PTLs) were measured at baseline and after each task. Mixed-model analysis was used to test for significant interaction effects between time and session. Results: An interaction effect between time and session occurred for perceived stress levels (P .001); perceived stress was significantly higher after the experimental task than after the control task (P .01). No interaction effects occurred for salivary cortisol levels, electrical PTs, or pressure PTLs. Although significant interactions did occur for electrical PTL (P .05) and pressure PT (P .001), the simple effects test could not identify significant differences between sessions at any time point. Conclusion: The PASAT evoked significant levels of perceived stress; however, pain sensitivity to mechanical or electrical stimuli was not significantly altered in response to the stress task, and the salivary cortisol levels were not altered in response to the PASAT. These results must be interpreted with caution, and more studies with larger study samples are needed to increase the clinical relevant understanding of the pain mechanisms and psychologic stress. Parole chiave: analgesia, facial pain, hyperalgesia, pain, stress