INTERVAL TRAINING IN PATIENTS WITH SEVERE CHRONIC HEART-FAILURE - ANALYSIS AND RECOMMENDATIONS FOR EXERCISE PROCEDURES

This study analyzes a new exercise training procedure, which includes interval exercise training on cycle ergometer (IntCT) (30-s work phase s/60-s recovery phases) and on treadmill (60-s work and recovery phase s each). Training was applied for 3 wk in 18 patients with severe chro nic heart failure (CHF) ((mean +/- SEM) age 52 +/- 2 yr, ejection frac tion 21 +/- 1%). Peak V over dotO(2) was increased from 12.2 +/- 0.7 t o 14.6 +/- 0.7 ml . kg(-1).(-1) owing to training (P < 0.001). A speci fic steep ramp test (work rate increments 25 W . 10 s(-1)) was develop ed to derive exercise intensity for work phases in IntCT, which was 50 % of the maximum work rate achieved. Steep ramp test was performed at the start of the study to determine the initial training work rate, th en weekly to readjust it. Since the maximum work rate achieved from th is test increased weekly (144 +/- 10 W --> 172 +/- 10 W --> 200 +/- 11 W; P < 0.001), the training work rate also increased (72 +/- 4 W --> 86 +/- 6 W --> 100 +/- 7 W; P < 0.001). Physical responses to IntCT we re measured. There was no significant change in heart rate, blood pres sure, and ratings of perceived exertion (RPE) using a Borg Scale betwe en the first and the third week of training (heart rate 88 +/- 3 b . m in(-1); blood pressure 115 +/- 4/80 +/- 2 mm Hg; leg fatigue 12 +/- 1; dyspnea 10 +/- 1). Mean lactate concentration (1.70 +/- 0.09 mmol . l (-1)) indicated an overall aerobic range of training intensity. When c ompared with the commonly used intensity level of 75% peak V over dotO (2) from an ordinary ramp test (work rate increments 12.5 W . min(-1)) , the performed training work rate was more than doubled (240%; P < 0. 0001) while cardiac stress was lower (86%; P < 0.01). Values of norepi nephrine and epinephrine as well as of RPE corresponded to those measu red at 75% peak V over dotO(2). Interval exercise training is thus rec ommended for selected patients with CHF as it allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. Using a ste ep ramp test, training work rate can be determined and readjusted week ly during initial training period.