Activation of the hypothalamic-pituitary adrenal axis in response to a verbal fluency task and associations with task performance
Speech fluency can be impaired in stressful situations. The aim of the present study was to investigate whether a verbal fluency task without any further stress induction by itself induces responses of the hypothalamic-pituitary adrenal (HPA) axis and of the sympathetic nervous system (SNS). The sample consisted of n = 85 participants (68.2% female; 33.3 {+/-} 15.2 years, BMI = 23.7 {+/-} 4.3 kg/m2) who performed two consecutive verbal fluency tasks for two minutes each. The categories were either stress or disease and animals or foods which were presented in a randomized order. Three saliva samples were collected, prior to the task (t0), immediately after (t1), and ten minutes after (t2). Salivary -amylase and cortisol were assessed. Furthermore, blood pressure, heart rate, and subjective ratings of actual stress perception, level of effort, and tiredness were measured. The verbal fluency task induced an HPA axis response with a maximum cortisol level at t2 (p < .001, {eta}p2 = .19) which was independent of task performance. Furthermore, subjective stress and effort as well of tiredness increased immediately after the task (all p < .001; all d [≥] 1.0). Tiredness immediately after the task was negatively correlated with task performance (p = .002). No -amylase, blood pressure or heart rate responses were found. We conclude that a verbal fluency task acts like an acute stressor that induces a cortisol response without the need of further (e.g., social-evaluative) stress components. Therefore, it is a little time-consuming alternative to other stress tasks that can be used in field studies with little effort.