Cardiac effects of exercise rehabilitation in hemodialysis patients

Exercise training has well documented beneficial effects in a variety of ca rdiac disorders. End stage renal disease patients present many cardiovascul ar complications and suffer from impaired exercise capacity. No study to da te has adequately examined the cardiac responses to exercise training in re nal patients on hemodialysis (HD). To determine the effects of an exercise rehabilitation program on the left ventricular function at rest and during submaximal effort, 38 end-stage renal disease patients on maintenance HD we re randomised into three groups. Sixteen of them (group A - mean age 46.4+/ -13.9 years), without clinical features of heart failure, participated in a 6-month supervised exercise renal rehabilitation program consisting of thr ee weekly sessions of aerobic training, 10 (group B - mean age 51.4+/-12.5 years) followed a moderate exercise program at home, and the other 12 (grou p C - mean age 50.2+/-7.9 years) were not trained and remained as controls. The level of anemia and the HD prescription remained constant during the s tudy. Fifteen sex- and age-matched sedentary individuals (group D - mean ag e 46.9+/-6.4 years) were the healthy controls. All subjects at the start an d end of the program underwent physical examination, laboratory tests, trea dmill exercise testing, M-mode and 2-D echocardiograms performed at rest an d at peak of supine bicycle exercise. Left ventricular volumes (EDV, ESV) a nd mass (LVM) were measured and ejection fraction (EF), stroke volume index (SVI) and cardiac output index (COI) were calculated by standard formulae. The maximal oxygen consumption increased by 43% (P<0.001) and the exercise time by 33% (P<0.001) after training in group A, by 17% (P<0.001) and 14% (P<0.01), respectively, in B, and both remained unchanged in group C. Train ing in group A was also associated with an increase in LVIDd (from 52.1+/-6 .4 to 54.0+/-6.1 mm, P<0.001) and LVM (226-+67 to 240+/-84 g, P<0.05) at re st with no change noted in groups B and C. Following a 6-month exercise tra ining in group A an increase was also found in the resting EF by 5% (P<0.01 ) and SVI by 14% (P<0.001). There was no change found in groups B and C. Su pine bicycle exercise after training in group A was associated with an impr ovement in EF by 14% compared to the pre-training change (P<0.001), SVI by 14% (P<0.001) and COI by 73% (P<0.001). These changes from rest to submaxim al exercise were less pronounced in group B following training at home. The untrained patients demonstrated no changes in LV systolic function over th e 6-month period. These results demonstrate that intense exercise training improves LV systolic function at rest in HD patients; both intense and mode rate physical training leads to enhanced cardiac performance during supine submaximal exercise. (C) 1999 Elsevier Science ireland Ltd. All rights rese rved.