Home-based exercise training modulates pro-oxidant substrates in patients with chronic heart failure

Abstract

Background: In chronic heart failure, oxidative stress is thought to lead to endothelial dysfunction. In this study, we assessed the effect of home-based exercise training on variables of the NO and purine pathways.

Methods and results: Eighteen patients and nine controls were randomly assigned in cross-over design to 8 weeks of exercise training (5 days/week, submaximal bicycle ergometer training, 30 min/day; calisthenics 9 min/day) and 8 weeks of sedentary lifestyle. Hypoxanthine, xanthine, l-arginine, asymmetric dimethylarginine (ADMA), symmetric DMA (SDMA) and nitrite were measured. In patients, exercise training led to an increase in peak VO(2) (p<0.003). At baseline hypoxanthine-a pro-oxidant substrate and marker of hypoxia-was higher in patients than in controls (24.6+/-4.3 vs. 11.9+/-4.2 micromol/l; p<0.05). After training there was a reduction in hypoxanthine (p<0.01). Nitrite levels were lower in patients (416+/-31 micromol/l) than in healthy controls (583+/-35 micromol/l, p<0.001). Although nitrite levels were highest after exercise, the changes did not reach statistical significance (p=n.s.). l-Arginine, ADMA, and SDMA levels were not different between groups and were not altered by exercise training.

Conclusions: Chronic heart failure is associated with increased levels of hypoxanthine and decreased levels of nitrite. This imbalance can be beneficially modulated by chronic home-based exercise training.