Age (p < 0.0001), female sex (p < 0.0001), NYHA class (p = 0.0003), BMI (p = 0.03), hemoglobin (<0.0001), NT-proBNP (p < 0.0001), left atrial volume index (p = 0.006), E/e’ (p < 0.0001), E/A (p < 0.0001), as well as a history of diabetes (p < 0.0001), atrial fibrillation (p = 0.04), hypertension (p < 0.0001), stroke (p = 0.01), and coronary artery disease (p = 0.02) were identified as significant predictors of the lowest VO2peak (i.e., quartile 1). Here, NPPB is linked to diabetes mellitus.