Intra-Dialytic Resistance Exercise for Hemodialysis Patients in Improving Physiological Measurements and Quality of Life: A Pilot Study

Bokai Chen

Department of Exercise and Fitness, The National Kidney Foundation, Singapore

*Correspondence to: Bokai Chen, Department of Exercise and Fitness, The National Kidney Foundation, Singapore.

Copyright © 2019 Bokai Chen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 10 February 2019
Published: 13 February 2019

Keywords: Intra-Dialytic Exercise; Hemodialysis; Chronic Kidney Disease; Glomerular Filtration Rate; Quality of Life; Physical Rehabilitation

Abstract

Hemodialysis (HD) patients generally have reduced functional capacity which leads to low level of physical activity. Exercise training in patients with end stage renal disease for a prolonged period of time has been shown to improve physical functioning and dialysis efficiency. While there are many literatures on aerobic exercises for HD patients reporting improved dialysis outcome and physical performance, resistance exercises have not been as extensively studied. Among the limited research on weight training during dialysis, it was found to improve functional performance and increase muscular strength. The present pilot study evaluates the feasibility of a relatively simple intradialytic resistance exercise intervention in improving HD patients’ physiological measurements and quality of life.

Abbreviations (if used)
Hemodialysis (HD)
Chronic Kidney Disease (CKD)
Glomeruar Filtration Rates (GFR)
Frequency, Intensity, Time and Type (FITT)
Kidney Disease Quality of Life (KDQOL-36)
Short Form (SF-12)
Physical Composite (PC)
Mental Composite (MC)

Introduction
Chronic kidney disease (CKD) is a gradual loss of kidney function over time [1]. The stages of chronic kidney disease are classified into 5 stages and the progression of the stages is based on the reduction in glomerular filtration rates (GFR) [2]. The two major causes of CKD are diabetes and high blood pressure, which accounts for up to 67% of the cases [1]. Studies have also shown that reduced GFR is linked with increased risks of cardiovascular events [3]. People with CKD have lower functional abilities [4] and an exercise programme may be beneficial for this population [4,5]. Currently, there is no cure for CKD but treatment can slow down the decline [6].

Exercise have shown the potential to improve health and quality of life in CKD patients, with stronger relationship of aerobic exercise and dialysis patients [7]. For haemodialysis (HD) patients, many studies have explored intra-dialytic cycling exercise intervention and have found positive results on health [8-10]. In these studies, patients cycled 10 to 30 minutes on an exercise peddler at moderate intensity during the first two hours of their HD sessions.

HD patients generally have reduced functional capacity which leads to low level of physical activity [11]. According to American College of Sports Medicine, individuals with stage 5 CKD have functional capacities which are about 50 - 80% of their healthy counterparts [12]. Their VO2 peak ranges between 15 - 25ml/kg/min and can increase with regular exercise by about 17 - 23% but generally will not achieve the same values with healthy equivalent controls [13]. Low-intensity aerobic exercises for HD patients have been reported to improve dialysis outcome and physical performance [14]. As the ideal FITT (Frequency, Intensity, Time and Type) principle of exercise prescription is not fully established for this population, modified recommendations for the general population can be used instead [12].

Exercise training in patients with end stage renal disease for a prolonged period of time has been shown to improve physical functioning and HD efficiency [15,16]. Weight training during dialysis have also been found to improve functional performance and strength [17]. The present study aims to evaluate the feasibility and effectiveness of an intra-dialytic resistance exercise intervention for HD patients in improving physiological measurements and quality of life.

Materials and Methods

Subjects
15 HD patients (age 60.9 ± 13.9 years) from 3 dialysis centers in Singapore were recruited for the study. All participants were informed of the study purposes and signed a consent form. Inclusion criteria includes undergoing maintenance HD for more than 12 months and good compliance to treatment modality without missing more than 2 dialysis sessions in the previous month. The exclusion criteria includes hospitalization in the prior month and amputation in the lower limbs.

Study Design
Intervention was carried out during every HD session for 12 weeks. It consisted of four exercises: arm curls, front shoulder raises, knee raises and knee extensions. The exercises were carried out using 0.5kg dumbbells for the arm exercises while 0.5kg ankle weights were used for the lower limbs exercises. Participants were instructed to perform the arm exercises on their non-fistula arm and the leg exercises on both legs.

In the first 4 weeks, participants completed 2 sets of 15 repetitions with 15 seconds of rest in between each set. Thereafter, the repetition in each set was increased by 5 for next 4 weeks (i.e. 2 sets of 20 repetitions with 15 seconds of rest in between sets). In the last 4 weeks, the repetitions in each set was further increased by another 5 repetitions (i.e. 2 sets of 25 repetitions with 15 seconds of rest in between sets).

Measurements
Pre dialysis heart rate and blood pressure are always recorded for each patient as part of the standard operation procedure in the dialysis centers. The records of the 12 weeks prior to the intervention were recalled and served as the baseline physiological measurements. These baseline data were used to compare with the data collected during the intervention. In addition, the OMNI Rating of Perceived Exertion scale was used to find out the participants’ perception of the level of effort they gave in performing the resistance exercises [18,19].

Participants also completed the Kidney Disease Quality of Life (KDQOL-36) questionnaire [20] before and after the intervention. It is widely used to evaluate the quality of life among people with CKD [21].

Statistical Analysis
SPSS 20.0 version for Windows was used for all statistical analyses. Paired sample t-test were performed to test the difference between the pre and post intervention heart rate, blood pressure, rate of perceived exertion and KDQOL-36 results. Statistical significance is defined as p-value of < .05 and .01.

Results
Patients showed significant improvements before and after the intervention in the following: Pre dialysis heart rate (79.9 ± 10.4 to 75.2 ± 10.1 beats per minute, p<0.01); Rate of Perceived Exertion (4.5 ± 2.1 to 3.2 ± 1.7, p<0.05) and Short Form (SF-12) Physical Composite scores (43.5 ± 8.2 to 48.5 ± 7.3, p<0.05) (Figure 1).

* p < .05

Figure 1: Pre and post SF-12 Physical Composite (PC) and Mental Composite (MC)

Discussion
HD patients have lower functional capacities compared to their healthy counterparts [4]. Muscle wasting has been associated with high risks for mortality in ESRD patients and exercise is one of the possible measures to aid prevention of muscle protein loss as well as maintain muscle function [22]. The benefits of exercising for patients with renal disease are not limited to increased energy but also include improved muscle physical functioning, improved blood pressure control, muscle strength, low levels of cholesterol and triglycerides, enhanced sleep and greater body weight control [23].

Resistance exercises are commonly known as strength training and is a form of physical activity that helps to improve muscular fitness by exercising a muscle or a muscle group against external resistance [12]. Strength training exercise program for older adults, when done regularly (e.g. twice or thrice weekly), can lead to an increase or maintenance in strength of muscles and connective tissues which help to combat frailty and reducing depression [24]. While resistance exercise training programs are lesser studied as compared to aerobic exercise in the CKD patient population, the evidence on this type of exercise had shown that they improved muscle strength and size, and potentially improve functioning [25].

Particularly for dialysis patients, it is found that those who did resistance exercises during dialysis had improvements in their physical fitness and psychological health, thereby improving their quality of life, as well as gaining a better dialysis efficiency of their treatment modality [26]. Research has also shown that intra-dialytic resistance exercise training is feasible, safe and well tolerated for patients [27]. Muscle strength is one of the most important determinants of physical function and also a key point to maintain daily activities of HD patients hence highlighting the potential of resistance exercise for this population [28].

The finding in the present study is consistent with other existing research which found out better perceived quality of life as an outcome from the intra-dialytic exercise interventions [29]. The SF-12 of KDQOL-36 assesses the generic physical and mental health of patients with kidney disease and has been validated in Singapore with her patient population [30]. It is compelling to know that the participants in the present study perceived a better physical health after the intra-dialytic exercise intervention.

The convenience sampling is a potential limitation of the study where the samples used in the study had some interest in the exercise intervention prior to the commencement of the study [31]. In additional, the study was unable to confirm that the improvements were because of the intervention. There are other existing studies, with leisure time physical activity records included, better in accounting for the factors contributing to their results [32].

Conclusion
Intra-dialytic resistance exercises have been shown to be effective in improving the health of HD patients. This study adds on to the evidence that weight bearing exercises during dialysis is also beneficial as evidenced by lower pre dialysis heart rate and perceived better physical health. This evidence further increases the support for the inclusion of exercise interventions during dialysis.

Acknowledgements
I thank the nurses in The National Kidney Foundation dialysis centers who helped me to retrieve the dialysis reports and the patients who participated in the study.

Conflicts of Interest
There was no conflict of interest as the scope of work of the researcher is independent of the treatment for the patients in the dialysis centers.

Bibliography