Exercise and Cognition in People with Chronic Kidney Disease

Exercise for those of us living with CKD is important and beneficial in so many ways. It can improve our physical function, assist with weight management, reduce cardiovascular risk factors, assist with controlling BP, and improve our emotional well-being and sleep.1 There is a large amount of readily available information about physical activity and exercise for the general population. However, this is not the case for those with CKD.2 As an additional benefit, it is believed that exercise may improve cognitive function, which can be impaired to varying degrees in people with CKD, depending on the stage of CKD, treatment modality (dialysis or transplantation), and presence of other chronic diseases.3 Exercise and physical activity target many of the risk factors that people with CKD may have, including cardiovascular disease, diabetes, and high BP, which are also risk factors of cognitive decline. In this study by Bradshaw et al.,3 they examine the question of the benefit of exercise interventions in improving cognition in people living with CKD through a systematic review and meta-analysis. Only 19 trials including 1160 participants were included in this analysis that highlighted that exercise had a small (statistically significant) effect on cognition in people with CKD with only a very small risk of harm. The specific type of exercise that was found to be beneficial was aerobic exercise. Aerobic exercise can be defined as any activity that uses large muscle groups, can be maintained continuously, and is rhythmic in nature.4 Examples of aerobic exercise include hiking, dancing, walking/jogging, cycling, and swimming, to name a few. This study highlighted that higher intensity exercise (that increases your heart rate) is most beneficial, yet throughout the journey of CKD, dialysis, and transplantation for those lucky enough to get one, we receive little education or information about how to exercise safely, often confused as to where to start. It is also complicated by the presence of comorbidities or disabilities. I have been blessed throughout my journey; in my life before CKD, I was a physiotherapist (physical therapist) for over 20 years, which has allowed me to work out how to progress exercises in a safe manner, despite many setbacks at different stages. I currently have a living donor transplant, and my exercise of choice is aqua aerobics. It is great as I am rehabbing from a knee injury, and so I had to find a substitute from walking/hiking, which was my preferred exercise previously. The World Health Organization recommends that adults need to perform at least 150–300 minutes of moderate activity in a week, along with 2–3 days a week that includes muscle strengthening and balance activities.1 With attending four sessions of 45 minutes of aqua, I can meet these requirements, but also importantly, it is very social, and I get to make many new friends, while singing along to great music. On the days I go to aqua, I find that my mental clarity and ability to churn out work is improved, and as a bonus, I sleep a lot more soundly. It was much harder to find my exercise of choice while I was on peritoneal dialysis. I was so exhausted and fatigued that it was a battle to just get through a day and do all my exchanges. I knew something had to change when I walked to my letter box, only 100 meters away, and was out of breath when I reached it. I was lucky to find Parkrun, a free 5-km timed run/shuffle/walk that was held in our rural town. I started very slowly and over a few months graduated to 1, 2, and then 3 km a day. My goal was to be able to easily do the whole given kilometers before receiving my transplant, scheduled in 5 months. Oh, the joy when I did that for the first time, about 2 months after I started my exercise journey. The biggest gains for me were feeling stronger, less fatigue, improved body image despite the tube, and mental clarity. I struggled on dialysis to read a book and concentrate, which is not normal for me. It was frustrating for me as the brain fog was present a lot, but exercise decreased its effect.2 This study forms an important part of the picture regarding the importance of exercise for people with CKD. However, this needs to progress to the development of exercise guidelines for both health professionals and patients to educate and inform about we can effectively exercise to reduce cognitive decline. One example of this can be seen in the Global Renal Exercise Network and the International Society of Peritoneal Dialysis Physical activity and exercise in PD practice recommendations.5 They highlight the scarcity of quality evidence in this area, but provide a great foundation for what is available. As a patient and physiotherapist, we need to have more readily available information for patients and their families. This information and education need to be aimed at different ages, different stages of CKD, different treatment modalities, and socioeconomic backgrounds and be available for people with CKD to access.