Heart rhythm biofeedback is a non-invasive physiological treatment that is administered via an app downloaded to personal smart phones. It involves participants attaching a wireless sensor to the ear that monitors heart rate that is displayed on the phone screen app. The participant is actively involved in modifying the heart biofeedback to achieve optimal levels of heart rate variability, an established indicator of health and well-being and a potential factor in chronic fatigue syndrome. The treatment lasts 8 weeks.

Hydrogen pills are mixed in a water glass that is ingested up to 3 times a day for 8 weeks. The hydrogen supplement is intended to reduce oxidative stress and inflammation both of which are implicated in the pathophysiology of chronic fatigue syndrome. This is an 8 week treatment.

This condition combines heart rhythm biofeedback and hydrogen water, as described above, which is intended to assess any additive or synergistic effects of the two treatments. This is an 8 week treatment.

Heart rhythm biofeedback is a non-invasive intervention intended to improve heart rate variability and physical resilience that is often limited in chronic fatigue syndrome

self-report measure of fatigue impact on functioning.Minimum value=1; Maximum value=7; Range: 1.00-7.00. High scores indicate more sever fatigue and a worse outcome.

Self-report measure of physical functioning. The short-form 36 physical function subscale is composed of ten items encompassing a hierarchical range of difficulties. Each item is scores on the basis of the limitations perceived by surveyed individuals. Item scores (1, 2, or 3) are summed to obtain a total score, which can then be scaled relative to its range. Higher scores indicate higher physical function.