Exercise During Dialysis Enhances Results And Overall Physical Performance

A five-month, low-intensity exercise intervention study of dialysis patients was recently carried out by Rehabilitation Therapy professor Cheryl King-VanVlack, member of the Cardiac, Circulation and Respiratory (CCR) group at Queen's, and a group of researchers from Queen's and Kingston General Hospital.

Results of the study, published in the most recent edition of the journal Archives of Physical Medicine and Rehabilitation, show that exercise during the process of dialysis increases by 20 per cent the removal of urea, one of the toxins collected in the body between dialysis sessions. This indicates that exercise during dialysis can enhance the treatment.

The study also suggests that physical function and stamina for the participants increases with the increased rate of toxin removal. During six-minute walk tests at weeks one, 10 and 20 of the study, the distance participants walked each time increased substantially.

"Enhanced dialysis efficacy over the long term may reduce the toxic effects of the 'uremic' syndrome, which refers to a myriad of complications associated with renal failure," says Dr. King-VanVlack. "Patients undergoing hemodialysis may have fewer complications, enhanced physical function and better quality of life by regular participation in an intra-dialytic exercise program."

Previously, most exercise programs for dialysis patients were instituted between sessions on non-dialysis days, and those programs that used exercise did not focus on dialysis efficacy -- the amount of toxins removed during a dialysis session.

Participants in this study exercised three times a week on stationary exercise bikes or mini-steppers placed in front of their dialysis chairs, for 30 minutes in each of the first two hours of dialysis.

Blood flow through the tissue is increased when exercise using lower extremity muscles allows capillaries to open up more to provide a greater surface area for exchange of substances from tissue to blood, researchers say. The increased blood flow moves more toxins from tissue to blood during dialysis for subsequent removal at the dialyser. The overall result is a greater removal of toxins in a given dialysis session or enhanced dialysis efficacy.

Other members of the research team are Dr. Edwin B. Toffelmire, Head of Nephrology at Kingston General Hospital and Trisha Parsons, a former Queen's Rehabilitation Science doctoral student. Findings from this study were presented at the Canadian Society of Nephrology meetings.