Studies indicate that acute experimental stress in healthy volunteers has a negative effect on the descending inhibitory pain control system and thus the ability to inhibit one painful stimulus with another (conditioned pain modulation [CPM]) although without effect on general pain sensitivity.
We used the QST to measure the thermal heat threshold (HTT), heat pain threshold (HPT), heat pain tolerance (HPT), heat pain tolerance (HPTo), and conditional pain modulation task (CPM-task).
Cuff pressure algometry at the lower legs was used to assess pain detection threshold (cPDT) and tolerance (cPTT) as well as conditioned pain modulation (CPM: change in cPDT during contralateral cuff pain conditioning) and temporal summation of pain (TSP: ten painful cuff stimulations assessed on a visual analogue scale [VAS]).
Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders.
Experimental pain parameters (pressure pain threshold, temporal summation = TS, conditioned pain modulation = CPM) and situational pain catastrophizing (Situational Catastrophizing Questionnaire = SCQ) were always assessed the evening before and the morning after sleep recording in a pain laboratory.
Decreased CPM potency and increased pain sensitivity in female participants were found, emphasizing the need to improve the understanding of its clinical consequences.
Two paradigms of pain modulation were administered to 191 healthy participants in a random order: Conditioned Pain Modulation in response to painful stimuli (CPM(painful)) tested by the coadministration of repeated short painful heat stimuli and a conditioning tonic cold pain stimulation; and Conditioned Pain Modulation in response to nonpainful stimuli (CPM(nonpainful)) tested similarly, except for using a painless conditioning stimulation.