Effectiveness and Safety of a Tele-Rehabilitation Program on Fatigue and Related Variables in Chronic Fatigue Syndrome and Post COVID Syndrome

Effectiveness and Safety of a Tele-rehabilitation Program Based on Mindful and Conscious Movement-based Exercise vs Conventional Low-intensity Exercise on Fatigue and Related Variables in Patients With Chronic Fatigue Syndrome/ Myalgic Encephalitis (CFS/ME) or Post COVID Syndrome (PCS)

This is a randomized, single-blind clinical trial that aims to evaluate the effectiveness of a tele-rehabilitation program based on mindful and conscious movement-based exercise (including adapted yoga, breathing exercises, and body awareness) compared to conventional exercise (low-intensity strength and aerobic training) and usual medical care (control group) over twelve weeks. The study is for people diagnosed with Chronic Fatigue Syndrome/ Myalgic Encephalitis (CFS/ME) or Post-Covid Syndrome (PCS).

We will also look at how the program affects the autonomic nervous system by measuring heart rate variability (HRV).

All sessions will be delivered remotely via Telehealth, so participants can take part from home. Assessments will be completed online at the beginning of the study, after three months (at the end of the intervention), and again three months later.

This clinical trial aims to evaluate the effectiveness of a tele-rehabilitation program based on mindful and conscious movement-based exercise (MBE) in individuals with Chronic Fatigue Syndrome/ Myalgic Encephalitis (CFS/ME) or Post-Covid Syndrome (PCS). The study includes three parallel groups: (1) MBE (including yoga, breathwork, and interoceptive awareness); (2) conventional low-intensity aerobic and strength exercise; and (3) usual medical care as a control. Participants will be randomly assigned to one of the three groups in a 1:1:1 ratio.

All interventions will be delivered via Telehealth, allowing participants to follow the program from home, which increases accessibility and is especially important for people experiencing severe fatigue. The intervention period will last 12 weeks. Both the conscious movement program and the conventional exercise program include a weekly live session of 45 minutes, progressively increased by 5 minutes per month to adapt to tolerance and avoid post-exertional symptom exacerbation. The program is designed with special attention to pacing, allowing participants to self-regulate effort levels based on daily condition and feedback from the body. Participants will also engage in a supportive WhatsApp group and complete digital daily logs.

The primary outcome is fatigue level (measured by the Chalder Fatigue Questionnaire). Secondary outcomes involve heart rate variability (HRV) as an indicator of autonomic function, physical capacity, pain, sleep quality, mental health, interoceptive awareness, quality of life, pain-related fear and somatic vigilance, adverse events, and adherence to the intervention. Assessment points are: baseline (T0), 3 months, at the end of intervention (T1), and follow-up at 6 months (T2). The study follows CONSORT guidelines and is single-blinded (evaluators/statisticians blinded to group assignment).

The expected sample size is 147 participants (49 per group), calculated for sufficient statistical power and accounting for 20% dropout. Recruitment will occur through patient associations, social media, and clinical collaborators. Data analysis will follow an intention-to-treat approach using appropriate mixed models for repeated measures.

The study addresses the need for safe and feasible therapeutic options for people with post-viral fatigue syndromes. It also explores the potential role of interoception and vagal modulation in symptom relief, contributing to a growing body of research on holistic, home-based interventions for chronic conditions.

Inclusion Criteria:

• Participants must be over 18 and under 70 years of age (to minimize the presence of comorbidities).
• Participants must meet the latest established diagnostic criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Post-Covid Syndrome, respectively.
• Participants must have access to a computer, tablet, or mobile device with an internet connection to attend videoconference sessions.
• Participants must have a mobile device compatible with the applications Cardiio: Heart Rate Monitor and Welltory, which will be used to measure heart rate (HR) and heart rate variability (HRV), respectively.
• Participants must be able to remain seated in a chair for at least 45 continuous minutes.
• Participants must have fluent comprehension of the Spanish language.
• Any comorbid condition that could explain the symptomatology associated with the syndrome (such as post-infectious organ damage, heart disease, neurological disorders, cancer, severe psychiatric illness, or metabolic syndrome) must have been ruled out by a physician.

Exclusion Criteria:

• Recent suspicion of comorbid conditions that could explain the syndrome's associated symptoms, not yet ruled out by a qualified healthcare professional.
• Inability to use basic software required for participation in the study (e.g., Microsoft Teams, completing a Google Forms questionnaire).
• Unwillingness to make minor adjustments to daily habits.