WALKING PERFORMANCE AND ECONOMY IN CHRONIC HEART-FAILURE PATIENTS PREAND POST EXERCISE TRAINING

The effect of a 3-week exercise programme on performance and economy o f walking was analysed in 16 male patients with chronic heart failure [mean age 51.8 (SD 6.9) years, height 174.9 (SD 6.3) cm, body mass 75. 3 (SD 11.5) kg, ejection fraction 20.8 (SD 5.0)%]. They were submitted to a cardiopulmonary exercise test on a cycle ergometer and a 6-min w alking test on a treadmill before and after the period of exercise tra ining. The training programme consisted of interval cycle (five times a week for 15 min), and treadmill ergometer training (three times a we ek for 10 min) at approximately 70% cycling peak oxygen uptake (over d otVO(2peak)) and supplementary exercises (three times a week for 20 mi n). Compared to the pre values cycling over dotVO(2peak) [11.9 (SD 2.9 ) vs 14.0 (SD 2.3) ml . kg(-1). min(-1)], maximal self paced walking s peed [0.68 (SD 0.33) vs 1.16 (SD 0.30) m . s(-1)], and net walking pow er [2.16 (SD 0.89) vs 2.73 (SD 0.91) W . kg(-1)] had increased (P < 0. 01) while net energy cost [3.31 (SD 0.66) vs 2.33 (SD 0.35) J . kg(-1) m(-1)] had decreased (P < 0.001) after the training period. Approxima tely 42% of the increase of walking speed resulted from a higher walki ng power output, whereas approximately 58% corresponded to a positive effect on walking economy. The improvement in walking economy was a fu nction of an increase in walking velocity itself and a result of a mor e efficient walking technique. These results would indicate that in pa tients with marked exercise intolerance, adequate exercise training pr ogrammes could contribute to favourable metabolic changes with positiv e effects on the economy of motion.