NPPB and congestive heart failure: This particular multicentre RCT (n = 149) reported improvements in all outcome measures except B-type natriuretic peptide (BNP) levels (namely, longer 6-minute walking distance, reduced cardiothoracic ratio on chest X-ray, and improved NYHA (New York Health Association) classification) in the infrared sauna-treated congestive heart failure group compared to control over only 2 weeks of intervention [31].