This trial investigated whether an 8-week regimen of yoga in addition to standard medical therapy would improve exercise capacity, inflammatory markers, and QoL in patients with heart failure (HF). New York Heart Association Class I–III HF patients were randomised to yoga treatment (YT) or standard medical therapy (MT). Measurements included a graded exercise test (GXT) to VO_2Peak and the following serum biomarkers: interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and extracellular superoxide dismutase (EC-SOD). The Minnesota Living with Heart Failure Questionnaire (MLHFQ) was administered to assess changes in QoL. A total of 19 patients were enrolled after the initial screening. Of the 19 patients, nine were randomised to YT and 10 to MT. Patients had a mean EF of 25%. GXT time and VO_2Peak were significantly improved in the YT versus MT groups (+18% in the YT and –7.5% in MT; vs. control and +17 in YT and –7.1 in MT). There were statistically significant reductions in serum levels of IL-6 and hsCRP and an increase in EC-SOD in the YT group. MLHFQ scores improved by 25.7% in the YT group and by 2.9% in the MT group.