Left ear transcutaneous vagus nerve stimulation will be applied to the participants in this group.A continuous electrical stimulation with a current frequency of 10 Heartz (Hz) with a current transit time of 300 μs was applied to the participants in both groups. The participants included in both groups were treated with taVNS with the "Vagustim" device for 20 minutes once a day and for a total of 10 sessions application was made.

Bilateral double ear transcutaneous vagus nerve stimulation will be applied to the participants in this group.A continuous electrical stimulation with a current frequency of 10 Heartz (Hz) with a current transit time of 300 μs was applied to the participants in both groups. The participants included in both groups were treated with taVNS with the "Vagustim" device for 20 minutes once a day and for a total of 10 sessions application was made.

Transcutaneous vagus nerve stimulation (taVNS) was performed with an FDA-approved Vagustim stimulation device and an electrode-shaped earpiece. In the participants included in the study and randomized to two groups, i) left ear taVNS was applied to the first group and ii) double-ear taVNS was applied to the second group.

HRV is a non-invasive method used to evaluate ANS activity and is a measure of heart rate change over a period of time. It analyzes the change in the beat-beat intervals of the heart and reflects the balance between PNS and SNS. During the analysis of heart rate variability measurement, the results obtained from sub-parameters such as stress index, time-domain and frequency-domain measurements allow evaluation of PNS and SNS activity.

The Fatigue Severity Scale, which is applied in the form of a questionnaire to determine the severity of fatigue accompanied by chronic diseases, consists of a total of 9 questions and according to the results obtained, it gives results as No Fatigue (<2.8 points) and chronic fatigue syndrome (>6.1 points).