The Beneficial Effects of Regular Physical Activity Intradialysis

Since 1980 ́s Goldberg demonstrate de benefits of exercise for hemodialysis patients as an adjuvant therapy improving metabolical state [1] and beginning a trend among hemodialysis units initially as an outpatient activity and later during dialyisis. Along time it has been demonstrated in randomized clinical trials the multiple beneficial effects of physical activity, attenuating the catabolic effects associated to hemodialysis and Chronic Kidney Disease (CKD) and improving general wellbeing among this population; it is a well-known fact that patients undergoing dialysis experiment a significant reduction in muscular mass, similar to elderly patients in whom muscular tissue is replaced by fat tissue; this muscular mass wasting correlates with lower functionality as shown by McIntyre in 2006 [2] according to his paper muscle mass, as assessed by the measurement of muscle Cross Sectional Area (CSA) corrected for linear height, was significantly lower in patients receiving dialysis (by about 9%), as compared with patients with CKD 4 reductions in muscle CSA appeared to be functionally significant.


Opinion
Since 1980´s Goldberg demonstrate de benefits of exercise for hemodialysis patients as an adjuvant therapy improving metabolical state [1] and beginning a trend among hemodialysis units initially as an outpatient activity and later during dialyisis. Along time it has been demonstrated in randomized clinical trials the multiple beneficial effects of physical activity, attenuating the catabolic effects associated to hemodialysis and Chronic Kidney Disease (CKD) and improving general wellbeing among this population; it is a well-known fact that patients undergoing dialysis experiment a significant reduction in muscular mass, similar to elderly patients in whom muscular tissue is replaced by fat tissue; this muscular mass wasting correlates with lower functionality as shown by McIntyre in 2006 [2] according to his paper muscle mass, as assessed by the measurement of muscle Cross Sectional Area (CSA) corrected for linear height, was significantly lower in patients receiving dialysis (by about 9%), as compared with patients with CKD 4 reductions in muscle CSA appeared to be functionally significant.
Muscle CSA was positively correlated with Sit-To-Stands (STS) 60 and negatively correlated with STS 5 assessments of overall physical condition in both males and females (all P<0.001). This effect could be palliated by physical activity. In our center in 1995 17 young patients (10 men and 7 women) who were receiving hemodialysis three times per week, were submitted to physical conditioning by pedaling without resistance at 50RPM a Monarck® ergometer for 15 minutes every hour during the 4 hours session performed 3 times a week for 12 weeks. We found that such intensity of exercise did not cause significant changes in blood pressure or heart rate and was well tolerated by patients. On average they recovered 4 kilograms of lean body weight and maintained a controlled pre-HD blood pressure without antihypertensive medications. Interestingly, the recovery of muscle mass was observed in both lower and upper limbs. A control group that did not perform physical activity during the same time period only gained one kilogram of weight [3].
Physical activity also has beneficial effects on functional capacity, anemia, cardiovascular risks factors and on psychosocial problems.
In 1986, Painter and colleagues [4] reported the effects of an exercise program that was delivered using a stationary cycle during the dialysis treatment and reported significant improvements in exercise capacity (VO2 peak) and improvements in blood pressure; these results were replicated in other single-center studies. Over time it also has been demonstrated that physical activity can impact increasing phosphorus and urea clearance the pedaling at 60RPM during the whole HDF session in our center improved the extraction of phosphate in 11±4%, this result has been reproduced several times with different subjects in other centers [5]. Other beneficial effect of physical activity found was the diminishing of drowsiness related to the alkaline load at the beginning of the dialysis, when patients do exercise, they do not fall asleep during treatment regularizing circadian cycle and reducing the need for sleeping drug [6]. It is important to mention that resistance to intensity cycling when compared to standard HD without exercise [8]. Related to these effects on intradialytic hypotension, the impact of exercise in tolerability of ultrafiltration has been measured in our Heterogeneity was found to be significant (I2=77%, p=0.005

Conclusion
In conclusion performing physical activity during hemodialysis can lead to an overall improvement in the well-being of this population, with evidence regarding beneficial effects on cardiovascular disease, the lead cause of death among hemodialysis patients, amelioration of muscular wasting that impacts so profoundly on functionality and even diminishing the effects of depression every hemodialysis center should consider include a physical activity program.