Mild Water-filtered Infrared-A Whole-body Hyperthermia in Patients With Post-COVID Syndrome (HyPoCo)

This study examines the efficacy of mild water-filtered whole-body hyperthermia during outpatient treatment in patients with post-COVID syndrome. The aim is to evaluate whether there can be an improvement in fatigue and quality of life. The duration of the study extends over a treatment period of approximately 2 weeks with two treatment units per week and a follow-up period of 3 months after the outpatient treatment.

A total of about 60 participants over 18 years of age are sought, who will be divided into two groups of equal size after inclusion in the study. All participants will receive the same amount of water-filtered whole-body hyperthermia (WBH) under application of 10 L/min oxygen within the outpatient setting. One group receives the gentle form of WBH, the other group receives the classic, mild WBH, which differ in the intensity of the radiation. Gentle hyperthermia serves as a control group for mild hyperthermia.

All abnormalities are documented by the responsible therapists, doctors and nurses.

Blood parameters are collected before the start, after 2 applications and after the last application during the clinical stay. The aim here is to determine the differential blood count and inflammatory and immune parameters; among other things, autoantibody production is to be examined and monitored during the course of the study. In order to check the possible effectiveness of the treatment, various questionnaire values are also collected. The survey will take place at 3 points in time (at the beginning, after completion of the 4 treatments and 3 months afterwards).

In addition, a diary will be filled out in which patients will provide information on their sleep, personal energy level and pain level as well as their daily step count in order to create an activity profile. All patients receive a paper diary and a pedometer adapted to their individual characteristics in advance. The diary is to be kept from week 0 to week 15.

After completion of the study, qualitative interviews lasting around 30-45 minutes will be conducted with 16-20 participants in weeks 8-10 of the follow-up period. Participants are selected on the basis of socio-demographic and clinical characteristics with the aim of obtaining a sample that is as heterogeneous as possible. The interviews are conducted by telephone.

Eligibility Criteria:
Inclusion Criteria:

* Patients aged between 18 and 75 years
* Confirmed diagnosis of post-COVID syndrome
* Fatigue: at least 51.5 points on the MFI-20 scale.
* Signed declaration of consent

Exclusion Criteria:

* Participation in other clinical studies
* Contraindications for hyperthermia (severe cardiovascular diseases with/above NYHA II, active tumor diseases, acute infections, hyperthyroidism (not adjusted), pregnant and breastfeeding women, epilepsy, high-grade cardiac arrhythmia including atrial fibrillation, multiple sclerosis, major skin lesions, photosensitivity disease, acute exacerbated bronchial asthma/COPD \[Gold II to IV\])
* Pleuritic chest pain
* Hyperthyroidism
* Poorly controlled diabetes mellitus
* Condition after critical illness due to COVID-19
* Patients with active tumor disease, with pneumological, rheumatic, endocrine or neurological concomitant diseases (including dementia, epilepsy, multiple sclerosis), in particular neurological diseases associated with cognitive or sensory disorders
* Severe liver or kidney diseases (liver cirrhosis, post liver transplant, autoimmune hepatitis, dialysis patients, post kidney transplant, acute kidney failure, autoimmune nephropathy)
* Patients with chronic cannabis use (exception: CBD for myalgia), long-term use of WHO class III opioids (e.g. for myalgia/joint pain), long-term use of immunosuppressive medication (steroids, biologics, MTX, leflunomide, azathioprine)
* Patients with psychiatric disorders (bipolar disorder, psychosis, schizophrenia, personality disorder)