Heart Rate Variability and Fatigue in Patients With Chronic Fatigue Syndrome After a Comprehensive Cognitive Behavior Group Therapy Program

In psychotherapy research, there is a general lack of studies that include objective measurements that provide information about the basic underlying mechanisms involved in behavioral and psychiatric conditions. In this pilot study, we investigated cardiovascular activity and self-reported fatigue in patients with Chronic Fatigue Syndrome (CFS) compared to normal healthy controls who served as a reference group. Furthermore, based on a one-group pre-post design, we investigated whether exposure to a Comprehensive Cognitive Behavior Therapy (CCBT) program resulted in any changes in cardiovascular activity and self-reported fatigue in CFS patients. Overall, 19 female CFS patients and 21 normal healthy controls were included in the study. Cardiovascular activity measurements were heart rate (HR), low frequency/high frequency (LF/HF ratio), and heart rate variability (the root mean of the squared successive differences; rMSSD). Fatigue was measured using the Chalder Fatigue Questionnaire. Analyses of the results indicated that, compared to normal healthy controls, CFS patients were characterized by higher HR and self-reported fatigue prior to exposure to the CCBT. Interestingly, CFS patients showed a significant decrease in LF/HF ratio indicating a shift in sympathovagal balance toward greater vagal activation, and levels of experienced fatigue subsequent to CCBT.