Exercising legs while having dialysis boosts toxin removal from blood: study
Provided by: Canadian Press
Written by: SHERYL UBELACKER
May. 11, 2006
TORONTO (CP) - Exercising while undergoing dialysis appears to improve removal of toxins from the body and increase physical stamina for patients with severe kidney disease, a Canadian study has found.
The five-month study by researchers at Queen’s University found that patients who took part in a total of one hour of lower-extremity exercise while sitting in a dialysis chair showed a 20 per cent increase in the amount of urea removed through their blood and were able to walk significantly farther in a standard stamina test.
Urea is a toxic byproduct from the metabolism of protein and is used as a marker for up to almost 100 possible toxic substances that build up in the body due to kidney failure.
Hemodialysis takes over the key jobs performed by healthy kidneys - cleaning the blood of toxins and extracting excess fluid that would normally be voided as urine. The three-times-a-week procedure, which circulates blood through the dialysis machine and then back into the patient, takes about four hours per session.
"The standard saying is: ‘What goes in, stays in,’ " principal researcher Cheryl King-VanVlack said of the effects of kidney failure. The buildup of toxins and excess fluid - especially in the 48 hours between dialysis bouts - can damage almost every organ system in the body, including the heart, blood vessels, muscles and the nervous system.
The resulting condition is known as uremic syndrome and it can halve a person’s capacity to perform physical activities, for instance, making it difficult to walk up stairs without puffing, she said.
“Therefore, it’s very essential in order to maintain as optimal a physical function as you can to try to have an exercise program,” King-VanVlack, chair of graduate studies in rehabilitative science at Queen’s, said from Kingston, Ont.
Exercising while undergoing dialysis not only increases stamina and helps stave off the nasty effects of uremic syndrome, it also gives often-bored patients something to do while stuck in the dialysis chair.
The Queen’s study involved 13 men and women in their early 20s to 80s, who exercised their legs three times a week on special stationary “bikes” or mini-steppers that were placed in front of their dialysis chairs, said King-VanVlack. The exercise was done for 30 minutes in each of the first two hours of dialysis, when patients were strongest.
King-VanVlack said that during exercise, blood flow through the tissue increases, opening up capillaries and providing a greater surface area for exchange of substances from tissue to blood. That allows more toxins to be removed.
Physical function and stamina also improved for participants. In standard endurance tests - in which a person walks as fast and as far as they can in six minutes - the distance patients were able to achieve rose by 14 per cent.
In a previously published paper looking at patient perceptions of the exercise program, one participant said “it gives you more stamina, more strength in your legs,” while another reported: “I definitely feel stronger . . . it’s a lot easier for going up stairs, just doing anything, I know I have a lot more strength.”
About 15,000 Canadians were on hemodialysis at the start of 2004, the Kidney Foundation of Canada, quoting the latest figures available, says on its website. That figure represents a doubling of cases since 1993; the number is predicted to double again in the next decade, due in part to a rising epidemic of potentially kidney-destroying Type 2 diabetes.
Commenting on the study, Toronto nephrologist Dr. Sheldon Tobe said that although the number of participants was small, the results are clinically significant.
“It shows us a way that we can actually improve efficiency of the dialysis procedure,” said Tobe of Sunnybrook Health Sciences Centre, who was not involved in the study. “It shows us that we can make our patients healthier and it does that all during a period of time when a patient is just sitting there tied to the machine, really not able to do much.”
Tobe believes the results, along with the findings of other studies, are enough to recommend that hospitals consider equipping dialysis units with sit-down exercise machines.
Creating space and equipment costs could pose some financial barriers, but the benefits would be worth it, he said.
“If we make (patients) stronger . . . that’s been correlated with fewer falls; fewer falls means fewer broken hips,” which represent a far greater drain on health-care resources and patients’ quality of life, Tobe said.
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