NPPB and heart failure: The main finding of this study was that HIIT can significantly reduce the levels of natriuretic peptide biomarkers (BNP and NT-proBNP) in patients with heart failure (SMD = −1.33, 95% CI: −2.55 to −0.11, P = 0.03), proving that HIIT may have better efficacy in the rehabilitation of heart failure patients.