Biofeedback equipment is classified by the Food and Drug Administration (FDA) as medical device class II and this type of equipment/treatment has shown evidence regarding stress management in post-Covid-19 syndrome.

The main objective of the study is to verify the feasibility of an HVR biofeedback training protocol in patients with long covid, and also to verify improvement induced by the technique in relation to: cognitive performance; pain perception; fatigue; quality of life; depressive and anxious symptoms

Long COVID is known by different names, and include a wide range of persistent symptoms that develop after SARS-CoV-2 infection and last for usually more than 12 weeks to months and up to 2 years, so far. The most common symptoms categorizable as neurological are fatigue, brain fog, and headache, among respiratory symptoms chest pain and shortness of breath, other less easily classifiable symptoms are heart palpitations and muscle pain. These symptoms are often debilitating enough to leave patients unable to work.

According to the WHO (2023), an estimated 17 million people were thought to be living with the long-term effects of COVID-19. Still now in less active pandemic phases, the risk of developing long COVID symptoms, at 10-20% of those infected, remains just as strong.

Trying to find a solution to manage symptoms through evidence-based practices is considered a current necessity to help health patients and professionals.

Biofeedback allows to learn self-regulation of some physiological processes through feedback of recorded parameters and the goal is improving health and its performances.

Biofeedback measures muscle activity, skin temperature, electrodermal activity (sudoriparous glands activity), respiration, heart rate, blood pressure, electrical brain activity and bloodstream, it also gives a quick feedback of those personal measurements to the patient, in this way biofeedback teaches people to have a more active role in maintaining a good personal, mental and physical health (quickly and thoroughly it give person feedback of activity and biofeedback teaches people to take a more active role in maintaining personal health and mental health and physical health).

Biofeedback equipment is classified by the Food and Drug Administration (FDA) as medical device class II and this type of equipment/treatment has shown evidence regarding stress management (evidence were shown as regards stress menagement).

The greatest benefits from using biofeedback are: improvement of sleep quality, improvement of self- efficacy, improvement of pain threshold, and improvement of emotional adjustment. In particular, a study conducted with HRV biofeedback, in which the sample learned resonance frequency breathing, showed dicreases in depression and pain and improved the person's system functioning.

Study objectives

The main objective of the study is to verify the feasibility of an HVR biofeedback training protocol in patients with Long Covid syndrome, and also to produce a preliminary measurement of the possible improvement induced by the technique in relation to:cognitive performance; pain perception; fatigue; quality of life; depressive and anxious symptoms. This measure will be useful to estimate the expected improvement in future case-control studies. Study design

This is a controlled clinical trial between usual care and biofeedback training plus usual care.

Inclusion Criteria:

• People who have contracted Covid-19 and have symptoms attributable to Long syndrome

Exclusion Criteria:

• patients with cognitive difficulties and/or diagnosis of mental retardation
• patients with severe comorbidities with the exception of anxious/depression symptoms arising in conjunction with the viral infection or long covid syndrome.