1. Discharged patients with COVID-19 pneumonia, 2. With dyspnea symptom (mMRC 2~3), 3. Aged 18~75 years old, 4. Have and can use smart phone (study subjects or family members), 5. Obtain the consent of the subjects or legal representative and sign the informed consent.

1. Discharged patients with COVID-19 pneumonia, 2. With dyspnea symptom (mMRC 2~3), 3. Aged 18~75 years old, 4. Have and can use smart phone (study subjects or family members), 5. Obtain the consent of the subjects or legal representative and sign the informed consent.