COVID-19 has a high spread rate, millions of people have been infected around the world. Patients complained of different symptoms as fever, dry cough and fatigue which is mild in about 80% of cases, but the severity of the case may progress to develop a respiratory distress or respiratory failure, which may require the need for intensive care unit (ICU)

COVID-19 has a high spread rate, millions of people have been infected around the world. Patients complained of different symptoms as fever, dry cough and fatigue which is mild in about 80% of cases, but the severity of the case may progress to develop a respiratory distress or respiratory failure, which may require the need for intensive care unit (ICU) Many patients with mild or severe COVID-19 do not make a full recovery and have a wide range of chronic symptoms for weeks or months after infection.

Post-COVID-19 syndrome is defined by persistent clinical signs and symptoms that appear while or after suffering COVID-19, persist for more than 12 weeks and cannot be explained by an alternative diagnosis.

Dyspnea is one of the most prevalent symptoms in post-covid-19 patients in up to 29% of patients with post COVID-19 syndrome.

Also, persistent dyspnea in post COVID-19 infection is frequent, it is so far, of unknown mechanism. Cardiopulmonary Exercise Test (CPET) is currently the gold standard technique in the differential diagnosis of dyspnea.

Cardiopulmonary exercise testing (CPET) is useful in the assessment of subjects with chronic lung conditions as it may help to: 1) recognize physiological factors limiting exercise (with or without the presence of psychogenic limiting factors); 2) identify these factors as potential therapeutic targets; 3) allow quantification of the level of impairment; 4) assess the effects of an intervention; and 5) provide prognostic information.

Inclusion Criteria:

• Confirmed or clinically and radiologically highly suspected Covid19-infection
• Symptom duration at least 12 weeks following first occurrence of symptoms
• Patients with dyspnea score 2, 3 and 4 on mMRC
• No other disease that better could explain the symptoms (dyspnea) than Covid-19

Exclusion Criteria:

• Age <18
• pregnant women
• terminally ill patients
• active covid-19 infection
• previous known severe pulmonary or heart disease
• inability to perform pulmonary function or cardiopulmonary exercise tests.

patients who are diagnosed as post covid_19 who were admittted to isolation unit of Assiut University Hospitals or visit the post covid_19 outpatient clinic