Whole unstimulated salivary flow rate decreases during acute stressful condition

Objective: To examine the influence of acute stress on salivary flow using a validated stressor paradigm. Study Design: This uniform crossover study consisted of 40 healthy adults who underwent the Trier Social Stress Test, consisting of a 5-minute mental arithmetic task (MAT), and a nonstressful task (NST), consisting of a 5-minute free speech task. The order of the tasks was counterbalanced and unstimulated whole saliva (UWS) was measured in 2 groups of 20 participants during each 5-minute task condition, with a 10-minute washout period between tasks. At baseline, mathematical ability was self-reported and psychological distress was measured using the Symptom Checklist-90-Revised. Heart rate (HR) and breathing rate (BR) were recorded during each task. Results: Age, sex, HR, BR, and psychological distress were similar between groups at baseline (P > .05). During the MAT, HR increased significantly and mean UWS flow rate decreased significantly compared with the NST (P < .001). Conclusions: An acute psychobiological stressor task was associated with a rapid decrease in salivary flow in adults. Thus, stress can contribute to reduced salivary flow and should be considered as a factor during the diagnostic workup of patients who complain of a dry mouth.