[Improvement of aerobic capacity in chronic congestive heart failure. Which training method is appropriate?]

Standardized guidelines for exercise training for patients with chronic congestive heart failure (CHF) have not been established. In the past, CHF patients involved in exercise training studies demonstrated a wide range of cardiac and functional impairment, with an ejection fraction between 18 and 35% and a peak VO2 between 12.2 and 25.4 ml/kg/min on average. For determination of training intensity, a VO2 between 40 and 70% of peak VO2 and/or training heart rate between 60 and 80% of peak heart rate was used. There was also a wide range for frequency (between 3 and 7 times per week) and duration of training (between 20 and 60 min per session). For aerobic exercise training only continuous training methods were applied. We have developed a new interval training method which allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. After only three weeks of training, the improvement in aerobic capacity was similar to that reported after longer training periods using continuous methods. To determine work rate for work phases of interval training, a special steep ramp test was developed. By analysis of acute physical responses to this testing procedure and to the interval training, both were proven to be tolerable in CHF patients, even if their ejection fraction is as low as 13%, or peak cardiac index not greater than 1.61/m2/min, and peak VO2 less than 8.5 ml/kg/min.