Achilleas Tourkantonis

EXERCISE TRAINING IN PATIENTS WITH END-STAGE RENAL DISEASE ON HEMODIALYSIS: COMPARISON OF THREE REHABILITATION PROGRAMS

Functional capacity of end-stage renal disease patients is dramatically impaired. Although exercise training programs appear to have beneficial morphological, functional and psychosocial effects in end-stage renal disease patients on hemodialysis (HD), the adherence rate is high. The purpose of this study was to compare the effects of three modes of exercise training on aerobic capacity and to identify the most favourable, efficient and preferable to patients on HD with regard to functional improvements and participation rate in the programs. Fifty-eight volunteer patients were screened for low-risk status and selected from the dialysis population. The 48 patients who completed the study protocol were randomly assigned either to one of the three training groups or to a control group. Sixteen of them (Group A - mean age 46.4+/-13.9 years) completed a 6-month supervised outpatient exercise renal rehabilitation program consisting of three weekly sessions of aerobic and strengthening training on the non-dialysis days; 10 (Group B - mean age 48.3+/-12.1 years) completed a 6-month exercise program during HD; 10 (Group C - mean age 51.4+/-12.5 years) followed an unsupervised moderate exercise program at home, and 12 patients (Group D-mean age 50.2+/-7.9 years) were used as patient controls. The level of anemia, the medications and the HD prescription remained stable during the study. Fifteen sex- and age-matched sedentary individuals (Group E - mean age 46.9+/-6.4 years) comprised a healthy control group for baseline data. All subjects at the beginning and end of the study underwent clinical examination, laboratory tests and a treadmill exercise test to fatigue endpoints with direct measurement of aerobic capacity. Group A had a higher dropout rate (24%) compared to groups B (17%) and C (17%). Peak oxygen consumption (VO2 peak) increased by 43% (p < 0.05), anaerobic threshold (VO2AT) by 37% (p < 0.05) and exercise time by 33% (p < 0.05) after training in Group A; by 24% (p < 0.05), 18% (p < 0.05) and 22% (p < 0.05), respectively, in B; and by 17% (p < 0.05), 8% (p < 0.05) and 14% (p < 0.05), respectively, in C; while both remained almost unchanged in Group D. These results demonstrate that intense exercise training on non-dialysis days is the most effective way of training, whereas exercise during HD is also effective and preferable.

Exercise Renal Rehabilitation Program: Psychosocial Effects

The aim of this study was to assess the psychosocial effects of exercise training on hemodialysis (HD) patients. Thirty-one uremic patients, aged 50.6+/-11.6 years, on maintenance HD were studied. Twenty patients were selected at random for a 6-month exercise renal rehabilitation program (ERRP) consisting of 3 weekly sessions of exercise training. The other 11 patients were assigned to sedentary control status. A formal psychosocial assessment, which included affective (Beck Depression Inventory, BDI), quality of life (Quality of Life Index, QLI) and personality (Eysenck Personality Questionnaire, EPQ) parameters, was performed with validated questionnaires at the beginning and the end of the ERRP. After training significant improvement occurred in physical capacity (VO2max increased from 16.8+/-6.2 to 23.2+/-7.6 ml/kg/min, p < 0.05). Although the level of depression did not differ betwen the 2 groups at pretesting, the ERRP group showed a decrease in their self-report of depression (decrease in BDI score value, from 21.0+/-10.4 to 13.7+/-9.5, p < 0.05) after the training program. From the relationship between the baseline levels of BDI depression and changes in VO2max in the ERRP group it was suggested that the most severely depressed patients got the greatest beneficial effects from exercise training. Moreover, trained patients demonstrated an improvement in QLI (from 6.3+/-1.5 to 9.0+/-0.9, p < 0.05). This improvement was found to be dependent on the participation in ERRP, the effects of the training and the improvement in the depression. All the above functional and psychosocial parameters remained unchanged in the controls. The results demonstrate that ERRP is an effective emotional therapeutic method for HD patients and improves their quality of life.

Cardiac effects of exercise rehabilitation in hemodialysis patients.

Exercise training has well documented beneficial effects in a variety of cardiac disorders. End stage renal disease patients present many cardiovascular complications and suffer from impaired exercise capacity. No study to date has adequately examined the cardiac responses to exercise training in renal 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 were 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 three 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 (group 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 study. Fifteen sex- and age-matched sedentary individuals (group D--mean age 46.9+/-6.4 years) were the healthy controls. All subjects at the start and end of the program underwent physical examination, laboratory tests, treadmill exercise testing, M-mode and 2-D echocardiograms performed at rest and at peak of supine bicycle exercise. Left ventricular volumes (EDV, ESV) and 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. Training 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 rest with no change noted in groups B and C. Following a 6-month exercise training 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. Supine bicycle exercise after training in group A was associated with an improvement 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 submaximal exercise were less pronounced in group B following training at home. The untrained patients demonstrated no changes in LV systolic function over the 6-month period. These results demonstrate that intense exercise training improves LV systolic function at rest in HD patients; both intense and moderate physical training leads to enhanced cardiac performance during supine submaximal exercise.

Depression, heart rate variability, and exercise training in dialysis patients:

Background Functional limitations, altered cardiac autonomic activity, and psychological distress are known disorders in chronic hemodialysis (HD) patients, relating to increased morbidity and mortality. The aim of this study was to examine the influence of an exercise training program on emotional parameters and heart rate variability (HRV) indices, as well as to determine whether emotional stress contributes to autonomic dysfunction in these patients. Methods Forty-four HD patients were randomly assigned into group A (24 patients, aged 46.3 ± 11.2 years), who participated in a 1-year intradialytic exercise training program and group B (20 patients, aged 45.8 ± 10.8 years), who were used as controls. At baseline and a year after, measures of HRV were obtained for the estimation of standard deviation of RR intervals, the mean square successive differences, percentage of RR intervals differing by more than 50 ms from the preceding RR interval (pNN50), and low to high frequency components. Emotional parameters (Beck Depression Inventory – BDI and Hospital Anxiety and Depression Scale – HADS) were also assessed by validated questionnaires. Moreover, all patients performed a spiroergometric study for the estimation of VO2peak. Results At baseline, all measurements were similar in the two groups and remained almost unchanged after a year in group B. After a year of training, VO2peak increased from 16.79 ± 5.24 to 22.33 ± 4.90 ml/kg per min (P >0.001) in group A. Trained patients also showed an increase in standard deviation of RR intervals by 58.8% (P >0.001), the mean square successive differences by 68.1% (P >0.001), pNN50 by 23.5% (P >0.001), and a low to high frequency ratio by 17.3% (P >0.001). Finally, at the end of the study, group A showed a decrease in BDI score by 34.5% (P >0.001) and HADS by 23.9% (P >0.001). Canonical correlation revealed significant inverse correlation among depression (in BDI and HADS) and HRV indices before and after exercise training. Conclusion Cardiac autonomic modulation seemed to be sensitive to the experience of persistent depression in HD patients. Significantly, exercise training reduced emotional distress and concomitantly improved HRV.