Home-based exercise training is an alternative for hemodialysis patients. This type of training enables them to exercise at their own convenience without being concerned about fatigue during dialysis, therefore resulting in a low dropout rate. Koh et al. in a randomized 6-month interventional study reported that home-based exercise training equally improved exercise capacity as intradialytic exercise in hemodialysis patients, if they could conduct home-based exercise with appropriate volume or intensity as advised [65]. However, because such programs cannot be supervised at all, it is difficult to ensure patient compliance with exercise. Whether the patients conduct exercise or not may be influenced by their motivation and mood. Therefore, in home-based exercise, practicing time and intensity are often insufficient, and there are a few studies, which report the effects of home-based exercise on cardiorespiratory function to be less than intradialysis exercise [64].

Although some dialysis facilities provide outpatient exercise programs, availability is still too low for the majority of dialysis patients to benefit from them. The survey in DOPPS (2005–2006) reported that only 10–20 % of facilities offered exercise programs to patients not on dialysis in most DOPPS countries [2]. Furthermore, patients’ adherence to such programs is not satisfactory. They often stop participating because of lack of spare time on non-dialysis days, transportation difficulties, high morbidity, and lack of motivation [63, 64]. Nevertheless, such supervised exercise training on non-dialysis days enables them to perform more aggressive, high-intensity exercise and further sports activities involving the movement of upper extremities, which is difficult during the dialysis treatment because of vascular access. Therefore, this method of exercise program has the greatest effect on improving cardiorespiratory capacity in maintenance hemodialysis patients as compared with intradialytic or home-based exercise [64].

Because it is widely known that the benefits of exercise are lost within a few weeks of non-training (detraining), it is important to incorporate exercise programs into routine care in the population on dialysis. Bennett et al. tried to identify contributing factors for sustaining hemodialysis exercise programs by examining 28 original studies and 14 review articles [66]. Other than the aforementioned elements necessary for improving patients’ adherence to exercise, such as exercise professionals’ involvement and conducting exercise programs during dialysis sessions, they identified other factors as follows: commitment to exercise by dialysis and medical staff, adequate space and equipment, interesting and stimulating programs or interventions, and addressing cost implications. Although it is not easy to meet all these requirements, the staffs in dialysis facilities need to make some effort toward creating an atmosphere in which the patients feel like participating continuously in physical activity or exercise.

In regard to the patients on continuous ambulatory peritoneal dialysis (CAPD), exercise capacity estimated by peak VO₂ and aerobic threshold remain unchanged regardless of whether the dialysis solution was retained in the peritoneal cavity or drained. However, exercise time was significantly shortened when the solution was retained directly due to the carrying of extra weight [67]. Therefore, exercising under conditions in which the solution is drained may be sustainable for this population.

In addition, difficulty in sustaining physical activity in patients with CKD has been attributed to anemia. A meta-analysis by Johansen et al. demonstrated that the treatment of anemia using erythropoiesis-stimulating agents significantly increased peak VO₂ by 24 % in hemodialysis patients, although many studies included were not controlled trials [68]. The improvement in anemia probably contributes to the sustainability of exercise, because the patients are freed from shortness of breath and fatigue, which are both major barriers to continuously participating in exercise programs, and could overcome discomfort or pain during exercise.

There is a very small amount of data from controlled studies to discuss or quantify the risks of exercise-induced adverse events in patients with CKD. However, to date, no published study on exercise training in hemodialysis patients has reported deaths or cardiovascular events. Therefore, it does not seem that exercise in dialysis patients necessarily carries additional risks.

According to a scientific statement from AHA, although the incidence of fatal and nonfatal cardiovascular events during exercise varies with the prevalence of cardiac disease in a study population, the rate is extremely low even among patients with chronic heart failure undertaking cardiac rehabilitation programs [69]. In contrast, the relative risk of cardiac arrest during vigorous exercise as compared with risk at other times is notably greater in patients who are unaccustomed to exercise [70]. Regular exercise participation, performed at low to moderate intensity, reduces the long-term risk of cardiac events both during exercise and at rest.

The exercise guide for nephrologists developed by the Life Options Rehabilitation Advisory Council suggested that to minimize the risks of exercise, nephrologists must be sure to provide adequate dialysis, manage ongoing medical concerns, control hypertension, and respond to symptoms suggestive of cardiac disease [71].

Patients with CKD, particularly, those on dialysis, have been exposed to the environment where they had a few opportunities to participate in physical activity due to conventional therapeutic policy. However, now it is evident that a sedentary lifestyle and low physical fitness result in a poor prognosis for this population. To engage all the patients in regular exercise, it is important that both patients and nephrologists discuss exercise positively and that the medical staff encourage the patients to exercise with a customized training program according to individual physical strength, medical concerns, and convenience.