Impact of low versus upper range intensity exercise training on endothelial function in patients with heart failure

Abstract

Purpose: To evaluate the impact of low versus upper range intensity exercise training on endothelial function, through assessment of circulating blood markers of endothelial function: the stable end product of Nitric Oxide (NOx), dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and xanthine oxidase (XO), in patients (pts) with Heart Failure (HF). Methods: Twenty male pts admitted at residential rehabilitation center (mean age 54.1±11.1 years) with ejection fraction <40%, were studied. Patients were randomized to low intensity exercise (40% heart rate reserve; LI group, n=9) and to upper range intensity exercise (70% heart rate reserve; UI group, n=11). Patients exercised twice a day at residential center over a period of 3 weeks. At baseline and 3 weeks later, in all pts values of NOx, ADMA, SDMA and XO were evaluated and exercise test was performed. Results: After 3 weeks NOx increased significantly in both groups: in LI group (from 33.2±4.1 to 38.8±6.0 μmol/l, P=0.006), and in UI group (from 32.3±6.9 to 52.2±14.5 μmol/l, P<0.0005), however increase in NOx was higher in UI than in LI group (P=0.041). Value of ADMA as well of SDMA decreased significantly in both groups after 3 weeks: in LI (P=0.003 and P=0.004) and in UI group (P=0.001 and P=0.071). At the end of the study value of ADMA was significantly lower in UI than in LI group (P=0.025).Compared to the baseline, value of XO at the end of the study was significantly lower in both groups (P<0.0005 both). After 3 weeks level and duration of test increased in both groups, however level of exercise test was significantly higher only in UI group, compared to baseline exercise test (P=0.005). Conclusion: Residential 3 weeks low, as well as, upper range intensity exercise training induced improvement in endothelial function in patients with HF. More significant increase of NOx, decrease of ADMA and increase of exercise capacity in UI group give an advantage to upper range over low intensity exercise training in patients with HF.