Research has shown that individuals who exercise have lower risk for chronic diseases than individuals who do not exercise.
Woolf et al (J Am Dietetic Assoc 2008;108:948-959) conducted a clinical trial comparing chronic disease risk factors in healthy women by the number of steps they took.
The active group, which took more than 7,500 steps as measured by a pedometer, had significantly lower serum insulin and leptin concentrations and lower body mass index (BMI) than the group taking fewer than 7,500 steps. Additionally, when the number of steps were expressed in tertiles, and the tertiles were statistically compared, both BMI and waist circumference were significantly lower in the tertile with the most steps.
CKD patient challenges
Patients who have chronic kidney disease (CKD) and especially those with end-stage renal disease on dialysis are quite likely to have multiple comorbidities (such as hypertension, cardiovascular disease, anemia of chronic disease, and diabetes) and take multiple medications (antihypertensive agents, phosphate binders, lipid and glucose lowering drugs, and others). Thus, routinely engaging in physical activity is more difficult and may be unsafe if the activity is not carefully monitored.
A 2006 Polish study Nephrol Dial Transplant 2006;21:1323-1327) showed that hemodialysis (HD) patients have significantly lower activity, as measured by steps with a pedometer, than patients not receiving HD (6,896 vs. 14,181 steps per 48 hours, respectively). More recently, Avesani et al (Nephrol Dial Transplant 2011; published online ahead of print) determined that HD patients’ activity was comparable with a sedentary life style.
This study used a multisensory device to measure steps taken, activity-related energy expenditure, and physical activity level. A high BMI or diabetic status was associated with a significantly lower physical activity level, and older age and diabetic status were associated with fewer steps. Additionally, all parameters were significantly lower during dialysis days when compared to non-dialysis days.
Improved quality of life
According to a 2011 review and meta-analysis by Heiwe and Jacobson (Cochrane Database Syst Rev 2011;) in patients with CKD, physical activity significantly improves quality of life (QoL), nutrition parameters (serum albumin and pre-albumin), blood pressure and heart rate, and aerobic and walking capacity.
However, even with the knowledge that patients with CKD are less active and that physical activity can improve key outcome parameters in this population, many clinicians would be unsure how to engage their patients in regular physical activity in a safe, well-monitored environment.
Two recent review articles have been published on how to initiate an exercise program in both CKD prior to dialysis (Am J Kidney Dis 2012; 59:126-134) and for patients on dialysis (Chonnam Med J 2011;47:61-65). Both reviews outline the types of exercise to consider and ways to monitor outcomes.
Exercising during dialysis
A 2010 study by Chen et al (Nephrol Dial Transplant 2010;25:1936-1943) outlines a very practical intradialytic exercise program that achieved positive outcomes. In this study, the authors enrolled 50 HD patients and randomized them to either intradialytic low intensity strength training or to stretching.
Patients engaged in resistance exercise during the second hour of dialysis, two times a week, for 48 sessions. The exercise consisted of a five-minute warm up and cool down and resistance exercise with ankle weights. The ankle weights were increased in 0.5 pound increments during the trial.
At the end of the trial, 44 patients could be analyzed for the primary outcome, the short physical performance battery score (SPPB). The investigators evaluated both physical parameters and QoL changes. The SPPB improved significantly in the strength training group compared with the stretching group (21% vs. 0.2%) and the short form-36 physical composite score improved significantly in the intervention group compared with the control group (21% vs. -0.2%). Interestingly, patient adherence to the exercise regime was 89%.
The Chen study shows a practical and inexpensive way to have dialysis patients exercise in the dialysis center, where they are closely monitored and the health care team can encourage and support the activity. CKD patients have many challenges that can decrease their QoL.
Engaging in physical activity on a regular basis, such as while on dialysis, may promote an anabolic state to enhance body composition and nutritional status thereby resulting in reduced hospitalization, improved mortality risk, and an overall improved QoL.
In a recent paper published in the American Journal of Kidney Diseases (2011;59:132-140), authors Kirsten L. Johansen, MD, and Patricia Painter, PhD, noted that the optimal recommendations for exercise in CKD patients have not been determined but that it is reasonable to follow recommendations contained in a 2002 report issued by an American College of Cardiology/American Heart Association task force for older adults.
These recommendations “are explicitly intended to be relevant to younger individuals with clinically significant chronic conditions and/or functional limitations, a description that applies to patients with CKD.”
The recommendations for older adults are as follows: “To promote and maintain health, older adults need moderate-intensity aerobic physical activity for a minimum of 30 minutes on five days each week or vigorous intensity aerobic activity for a minimum of 20 minutes on three days each week.”