Exercise training improves cardiovascular fitness in people receiving haemodialysis for chronic renal disease

Abstract

To review the effects of exercise training on cardiovascular fitness, cardiac function, strength, quality of life and safety in people on regular haemodialysis for chronic renal disease. CENTRAL, Embase, Medline and CINAHL, searched up to December 2010. Reference lists of included studies were hand searched for further eligible trials. Randomised controlled trials involving people with chronic renal disease on regular haemodialysis, in which exercise training was compared to no training or in which different exercise modalities were compared. Trials assessing peak oxygen consumption as a measure of cardiopulmonary fitness were included. Other outcome measures were cardiac function, strength, quality of life, and safety. Exercise adherence was also considered. : Two reviewers determined the eligibility of studies. Methodological quality was assessed using the Jadad scale. Of 69 studies initially identified by the searches, 15 studies involving a total of 565 participants were eligible and were included in the review. Study quality ranged from 1 to 3 out of 5 on the Jadad scale. Eight studies involving 365 participants compared cardiovascular fitness between training and control groups. The pooled result showed significantly greater peak oxygen consumption in the training group by 5mL per kg per min (95% CI 4 to 7). Subgroup analyses indicated that this effect was greater among studies where the exercise training was of longer duration, was not performed during dialysis, and included strength training as opposed to aerobic training alone. The exercise group also had significantly lower heart rate variability (ie, heart rate SD reduced by 16, 95% CI 8 to 24) and tended to have greater left ventricular ejection fraction (by 5%, 95% CI 0 to 9). Two studies measured cross-sectional area of limb muscles. Both showed significantly greater improvement in the exercise group, but only one also showed significantly greater strength. The effect of exercise training on quality of life was not clear, however the exercise training appeared to be safe with no deaths reported during exercise training. Among those patients originally approached about participation, 25% were ineligible due to comorbidities and a further 28% refused to participate. Of those who commenced exercise, 15% withdrew, which was similar to the dropout rate in the control group. Exercise training is safe, substantially improves cardiovascular fitness and reduces cardiac variability. To maximise the effect on cardiovascular fitness, the training should be longterm, be performed outside of haemodialysis periods, and include strength as well as aerobic training.