Wu CW, et al. - In this study performed on 79 patients with chronic obstructive pulmonary disease (COPD), researchers intended to corroborate the link between oxygen pulse (O₂P), health-related quality of life (HRQL), exercise capacity, severe exacerbation of COPD, and other parameters in exercise testing. The participants were assessed via lung function testing, a cardiopulmonary exercise test, Borg Dyspnea Scale evaluation, completion of the St. George’s Respiratory Questionnaire, and echocardiography. Compared with patients with impaired peak O₂P, those having normal peak O₂P exhibited higher exercise capacity (peak oxygen uptake and work rate), better HRQL, lower dyspnea score, lower COPD-associated hospitalizations, and higher circulatory and ventilator parameters. Findings revealed a significant influence of peak O₂P on exercise capacity, HRQL, dyspnea, COPD-related hospitalization, and circulatory and ventilatory functions in COPD patients. Also, strong and moderate links of anaerobic threshold and forced expiratory volume in one second with peak O₂P, respectively, were revealed. In this study, peak O₂P was identified as a crucial indicator of disease severity for COPD patients.