The aftermath of severe COVID-19 frequently involves considerable cardiopulmonary damage, necessitating rehabilitation. This study aimed to evaluate the impact of COVID-19 on cardiopulmonary health and assess the effectiveness of various rehabilitative interventions. Conducted between September 2021 and September 2022, this prospective study included patients who had been diagnosed with severe COVID-19 and admitted at the “Victor Babes” Infectious Diseases and Pulmonology Hospital, Timisoara, Romania. The patients were stratified into low- and high-intensity rehabilitation groups. The rehabilitation protocols were individually tailored, and the patient recovery was closely monitored over a 3-month period. Our cohort comprised 84 patients, with a mean age of 56.3 years for the low-intensity group (n= 42) and 53.1 years for the high-intensity group (n= 42). Both groups showed significant improvements in the lung injury area, need for oxygen supplementation, ejection fraction, systolic pulmonary artery pressure, and forced vital capacity. Additionally, considerable enhancements were observed in maximal voluntary ventilation, FEV1, FEV1/FVC ratio, peak expiratory flow, and forced expiratory flow at 25–75%. The work intensity also demonstrated substantial improvements from the initial testing to the 3-month mark in both groups. This study provides evidence that personalized, targeted rehabilitation strategies can improve long-term cardiopulmonary health in patients recovering from severe COVID-19, proving both low-intensity and high-intensity training as sufficient to improve heart and lung function if performed correctly and over a relatively short duration of 3 months. The study findings underscore the importance of implementing comprehensive cardiopulmonary rehabilitation protocols in the care of post-COVID-19 patients and highlight the value of stratified rehabilitation intensity based on individual patient dynamics and recovery features.