Coronavirus disease 2019 (COVID-19) is a serious respiratory disease that results from infection with a newly discovered coronavirus (SARS-COV-2). Unfortunately, COVID-19 is not only a short-term infection but that patients (pts) recovering from SARS-COV2 infection complain of persisting symptoms including: fatigue, diffuse myalgia and weakness, which may lead to chronic fatigue syndrome. There is currently no evidence that nutritional supplements and/or physical exercise can assist in the recovery of pts with chronic fatigue syndrome. 1-Methylnicotinamide (1-MNA) is an endogenic substance that is produced in the liver when nicotinic acid is metabolized. 1-MNA demonstrates anti-inflammatory and anti-thrombotic properties. Therefore, we investigated whether 1-MNA supplements could improve exercise tolerance and decrease fatigue among patients recovering from SARS-COV-2.

The study population was composed of pts after COVID-19, expressing subjective feelings of limited tolerance to exercise. The selected pts were randomized into two groups: GrM0 - without supplementation; GrM1 - with 1-MNA supplementation. At the beginning of the study (Phase 0), in both groups, a 6-minute walk test (6MWT) was carried out and fatigue assessment with Fatigue Severity Scale (FSS) was performed. After 1 month (Phase 1), a fol-low up FSS and 6MWT once more were performed in both groups.

Inclusion Criteria:

• Patients after COVID-19
• Patients expressing subjective feelings of limited tolerance to exercise and above 50% greater fatigue compared to their pre-COVID-19 levels (symptoms must have continued for at least four weeks since the last symptoms of infection)

Exclusion Criteria:

• Patients with cardiological complications
• Patients with pulmonological complications
• Patients with Chronic Obstructive Pulmonary Disease and/or asthma

Patients after COVID-19, expressing subjective feelings of limited tolerance to exercise and above 50% greater fatigue compared to their pre-COVID-19 levels. These symptoms must have continued for at least four weeks since the last symptoms of infection.