Psychophysiological Characteristics of Women Suffering from Stress-Related Fatigue

Stress-related fatigue has been attributed to excessive sympathetic nervous system and hypothalamic pituitary adrenal (HPA) axis activation, but findings have been equivocal as to whether the HPA axis or the autonomic nervous system (ANS) are affected in this condition and how. Whether task performance deficits are associated with this condition is also uncertain. The present study investigated possible differences between women with stress-related fatigue and healthy women in heart rate variability (H RV) and other autonomic and respiratory measures, task performance and in salivary cortisol response to awakening. Thirty-six women with stress-related fatigue were compared with 19 female healthy controls matched in age. Four indices of HRV and other autonomic and respiratory measures were recorded during baseline, task performance and relaxation phases of a laboratory session. Saliva cortisol was measured four times during the hour after awakening. The fatigued group showed less HRV in three measures, higher temperature, lower O-2 saturation at the surface of the finger, lower end-tidal pCO(2), and greater cortisol response. This group responded faster on the task but with more errors. Women with stress-related fatigue show signs of hyperarousal on ANS, respiratory and HPA axis measures. The lower H RV may indicate greater cardiovascular risk. Results for task performance confirm subjectively reported deficits. Copyright (C) 2009 John Wiley & Sons, Ltd.