EFFECTS OF REGULAR EXERCISE ON ANXIETY, DEPRESSION, AND QUALITY OF LIFE IN MAINTENANCE HEMODIALYSIS PATIENTS

Abstract

Background: Psychological problems such as depression and anxiety are common in hemodialysis patients. In several studies, exercise programs were effective in relieving depression or anxiety in these patients, although not all agree. Purpose: In this study, we evaluated the effects of an exercise program on exercise capacity, anxiety, depression and quality of life in maintenance hemodialysis patients. Methods: Twenty hemodialysis patients were enrolled in the study. Six patients were later excluded; two due to anemia, one due to nausea with vomiting during exercise, one due to a neurologic problem, and the other two due to noncompliance. Thus, fourteen patients, 3 men and 11 women, aged 42 ± 10 years, completed the study. The exercise program composed of bicycle ergometer, treadmill or upper limb ergometer, 60 min per session, 3 times per week, for 12 weeks. At the beginning and the end of the exercise program, the exercise capacity was determined by measuring the maximal oxygen consumption and exercise duration. In addition, psychological tests for the assessment of depression, anxiety and quality of life were performed. Results: Maximal oxygen consumption was increased from 26.3 ± 4.6 mL/kg/min to 29.8 ± 4.9 mL/kg/min (p = 0.013). Exercise duration was 483 ± 138 s at the start. At the end of the exercise program it was increased to 607 ± 119 s (p = 0.002). The score of anxiety was significantly improved from 47.9 ± 5.9 to 42.8 ± 6.3 after exercise (p = 0.004). Though it did not reach statistical significance there was a trend of improvement in depression (from 44.8 ± 8.4 to 39.7 ± 6.4, p = 0.073). The score of quality of life also showed a significant improvement (from 124.5 ± 16.5 to 133.6 ± 19.3, p = 0.031). Conclusion: The results of this study indicate that an appropriate application of exercise program would improve the psychological status in long-term maintenance hemodialysis patients.

• Anxiety
• Depression
• Exercise
• Hemodialysis
• Quality of life

INTRODUCTION

End-stage renal disease (ESRD) is not a curable disease, and requires a lifelong dialysis treatment unless it is managed by a renal transplantation. ESRD patients on hemodialysis, spend about four hours in each session of hemodialysis three times per week. Therefore, most of hemodialysis patients can not have a regular job, and commonly suffer from psychological problems such as depression and anxiety.

Work capacity of hemodialysis patients as measured by maximal oxygen consumption (VO_2max) has been reported to be significantly lower than that of normal subjects.[[1]] Multiple factors, such as anemia, concurrent coronary artery disease, uremic myopathy and depression may be responsible for it.[[2]], [[3]]

Physical inactivity is a major contributor to premature morbidity and mortality from chronic illness. Though a sudden vigorous exercise program in the unfit may increase the risk of myocardial infarction and sudden death, regular exercise of moderate intensity is known to have a variety of benefits on mental health as well as on physical health. Some of the benefits of exercise have also been reported in hemodialysis patients. Several studies have reported that the work capacity of ESRD patients increased after the application of an exercise program.[[1]], [[4]] In addition, a decrease in blood pressure,[[5]] improvement of lipid profile,[[6]] improvement of anemia[[7]] have also been reported in ESRD patients on an exercise program.

There are several previous studies that mentioned the effects of exercise training on the psychological status in hemodialysis patients. Carney et al.[[8]] reported that after 6 months of an aerobic exercise training program, 10 exercisers showed a significant decrease in dysphoric mood when compared to 7 patients attending the support group. Kouidi et al.[[9]] also reported improvement of depression and quality of life after a 6-month exercise program. On the contrary, in a study by Shalom et al.,[[4]] a 12-week exercise program did not show a significant benefit on the depression or anxiety in fourteen hemodialysis patients.

In this study, we evaluated the effects of a 12-week exercise program on the work capacity, anxiety, depression and quality of life in maintenance hemodialysis patients.

PATIENTS AND METHODS

Patients

Twenty patients were selected from a pool of 250 patients with end-stage renal disease who had been on maintenance hemodialysis at Asan Medical Center, Seoul, Korea. In order to be included, the patients had to have been treated for ESRD with maintenance hemodialysis three times a week for at least three months, had to be 18 years of age or older, had to provide informed consent, had to have the level of hemoglobin higher than 8 g/dL, had to be able to walk without the need of help, and had to have no severe physical or psychological problems to be treated. The criteria for exclusion were uncontrolled hypertension or hyperglycemia, the presence of heart failure or arrhythmia, and cerebrovascular accident. None of the patients was on antidepressants or other psychotropic agents.

Methods

The following information was obtained from each patient; age, sex, cause of end-stage renal disease, and duration of hemodialysis. At the beginning and the end of this study, the patients underwent psychological tests for the assessment of depression, anxiety and quality of life. The physical work capacity was also determined by the measurement of VO_2max and duration of exercise during a graded exercise treadmill stress test, using a modified Bruce protocol.

Exercise Program

The patients visited the sports medical center of our hospital 3 times a week on the ‘off’ dialysis days for 12 weeks to take exercise for 60 min in a session under the supervision of a physician.

Each exercise session was consisted of a warm-up for 10 min, bicycle ergometer, treadmill or upper limb ergometer for 40 min, and cool-down for 10 min. The target of exercise intensity was set at 40–60% of the peak heart rate as determined in the baseline treadmill stress test.

Treadmill Test

The physical work capacity was determined by the measurements of performance including VO_2max during a volitional exhausting graded exercise treadmill test, according to a modified Bruce protocol. Theoretically, maximal oxygen consumption is the oxygen amount that one can uptake maximally during exercise. In this study, oxygen consumption during the stress test was determined by analyzing the fractions of oxygen and carbon dioxide in the expired air (MedGraphics, Cardiopulmonary Diagnostic System, USA). The recorded maximum heart rate (HRmax), blood pressure and VO_2max determined the exercise prescription.

Depression

Depression was assessed by Self-rating Depression Scale (SDS), which was originally developed by Zung et al.,[[10]] was translated and standardized for the Korean population. It composed of 20 items, each with a 1–4 grading system. The total score ranges from 20 to 80, with the higher value indicating more severe depression.

Anxiety

Anxiety was assessed by the state anxiety inventory, which was originally developed by Spielberger et al.,[[11]] was translated and standardized for the Korean population. It composed of 20 items, each with a 1–4 grading system. The total score ranges from 20 to 80, with the higher value indicating more severe anxiety.

Quality of Life

Patients’ subjective quality of life outcomes were assessed by the Korean version of a ESRD specific instrument developed by Kim.[[12]] It composed of 41 items, each with a 1–5 grading system. The total score ranges from 41 to 205, with the higher value indicating better quality of life.

Statistical Analysis

Data are presented as mean ± SD. Pre- and post-study VO_2max, scores of depression, anxiety and quality of life were compared by the Wilcoxon's signed-rank test. P < 0.05 was considered significant.

RESULTS

Of the 20 hemodialysis patients, 14 patients, 3 men and 11 women, completed the 12-week exercise program. Two patients were dropped out due to anemia, one due to nausea and vomiting, one due to a neurologic problem. The other two were excluded due to noncompliance.

The clinical characteristics of the patients completed the study are shown in Table 1. The mean age of the patients was 42 ± 10 years. The mean duration of hemodialysis was 41 ± 44 months.

Table 1. Clinical Characteristics of the Patients

	Subjects (n = 14)
Age (years)	42 ± 10 (23–58)
Sex (M : F)	3 : 11
Duration of hemodialysis (months)	41 ± 45 (3–147)
Underlying disease
Small kidneys of unknown etiology	9
Diabetes mellitus	3
Chronic glomerulonephritis	1
Hypertensive nephrosclerosis	1

Mean ± SD (range).

Exercise Capacity

The changes of exercise capacity before and after the treatment are shown in Table 2. Work capacity as measured by VO_2max and exercise duration showed a significant improvement after the 12-week exercise program. VO_2max was increased from 26.3 ± 4.6 mL/kg/min to 29.8 ± 4.9 mL/kg/min (p = 0.013). (Figure 1) Exercise duration was 483 ± 138 s at the start. At the end of the exercise program it was increased to 607 ± 119 s (p = 0.002). There was no difference in hematocrit before (27.8 ± 2.3%) and after (28.2 ± 2.1%) the exercise program.

Figure 1. Changes in VO_2max of the patients after the exercise program.

Table 2. The Work Capacity of the Patients Before and After the Exercise Program

	Before Exercise	After Exercise	p value
Maximal oxygen consumption (mL/kg/min)	26.3±4.6	29.8±4.9	0.013
Exercise Duration (s)	483±138	607±119	0.002
Hematocrit (%)	27.8±2.3	28.2±2.1	0.572

Mean±SD.

Depression

The score of depression was 44.8 ± 8.4 at the start of the exercise program. After the exercise program it was decreased to 39.7 ± 6.4 (p = 0.073) though the difference was not statistically significant. (Table 3)

Table 3. Depression, Anxiety, and Quality of Life in the Patients Before and After the Exercise Program

	Before Exercise	After Exercise	p value
Depression	44.8 ± 8.4	39.7 ± 6.4	0.073
Anxiety	47.9 ± 5.9	42.8 ± 6.3	0.004
Quality of life	124.5 ± 16.5	133.6 ± 19.3	0.031

Mean ± SD.

Anxiety

The score of anxiety was significantly improved from 47.9 ± 5.9 to 42.8 ± 6.3 after the exercise program (p = 0.004). (Table 3)

Quality of Life

The score of quality of life also showed a significant improvement (from 124.5 ± 16.5 to 133.6 ± 19.3; p = 0.031) after the exercise program. (Table 3)

DISCUSSION

Work capacity was increased after the 12-week exercise program. The exercise program also had beneficial effects on anxiety and quality of life in our hemodialysis patients. Maximal oxygen consumption is low in hemodialysis patients as compared to normal subjects.[[1]] Pre-exercise maximal oxygen consumption in our patients was 26.3 ± 4.6 mL/kg/min and it was increased to 29.8 ± 4.9 mL/kg/min at the end of the exercise program. Increase in work capacity as measured by maximal oxygen consumption and exercise duration after the exercise program in the present study is in agreement with the previous studies. Zebetakis et al.[[7]] reported 13% increase in maximal oxygen consumption after treadmill exercise, 25–45 min per session, 3 times per week, for 10 weeks in 5 hemodialysis patients. In the study by Shalom et al.[[4]] there was 42% improvement in work capacity in the group of 5 hemodialysis and 2 peritoneal dialysis patients who attended more than 50% of the sessions held three times each week for 12 weeks. Regular exercise imposes demand and stress on multiple organ and enzyme system. The responding long-term adaptation of the circulatory, respiratory, endocrine, nervous and musculoskeletal system is thought to cause the increase in work capacity.

Due to the persistent physical and psychological stress a significant portion of hemodialysis patients have emotional problems.[[13]] Depression and anxiety are highly prevalent in these patients. In the study by De-Nour,[[14]] 62% of the hemodialysis patients suffered from depression. By suppressing appetite, depression can result in malnutrition, which in turn increase the mortality in these patients.

The psychological benefit of exercise in hemodialysis patients was at first suggested by Goldberg et al.[[15]] In the psychological test of four hemodialysis patients, exercise training was associated with an improvement in depression, hostility, anxiety, social interaction, and outlook for the future. In a study by Shalom et al.[[4]] of fourteen hemodialysis patients, however, a 12-week exercise program did not show a significant change in depression, anxiety, or aggressiveness. On the contrary, Kouidi et al.[[9]] reported improvement of depression and quality of life after a 6-month exercise program. The result of this study is in agreement with the latter study. Anxiety was significantly relieved. There was a tendency of decrease in depression after exercise program though it was not statistically significant.

Quality of life is an important outcome indicator in assessing the effects of the therapeutic strategies. In our patients, the score of quality of life was increased after the exercise program. This is in consistent with the study by Lo et al.[[16]] Other subjective responses of the patients to the exercise program were as the followings; “sleep well”, “walk more comfortably”, “feel less fatigue”, “feel well”.

Exercise should be prescribed systematically and individualized according to the individual characteristics. Bicycle ergometer, walking, jogging and swimming are recommended as aerobic exercise to hemodialysis patients. The strength of exercise is determined at 65 ˜ 88% of the maximal strength on treadmill test. It is suggested that to be effective, exercise should be done 30–45 min per session, 3 times per week.[[6]]

Cardiovascular disease is commonly present in hemodialysis patients. Especially diabetic patients on hemodialysis are likely to have ischemic heart disease. Thus, before the introduction of exercise program, careful evaluation of health status should be preceded. This study and the previous studies evaluating the effect of exercise in ESRD patients indicate that exercise of moderate intensity can be applied in ESRD patients without a significant risk if performed after a careful evaluation of health status by a physician.

In conclusion, an appropriate application of exercise program would improve the psychological status including anxiety and increase quality of life as well as improve work capacity in maintenance hemodialysis patients.