NEW YORK (Reuters Health) - Patients with end stage renal disease (ESRD) can safely participate in high intensity, progressive resistance training during routine hemodialysis, according to a study conducted in Sydney, Australia.

Within 3 months, weight training increases patients' muscle status and strength, reduces blood levels of inflammatory markers, and leads to improved quality of life, the research team reports.

Patients with ESRD suffer from muscle wasting, lead author Dr. Bobby Cheema, from the University of Sydney, and colleagues point out. According to their report in the May issue of the Journal of the American Society of Nephrology, muscle wasting is one of the strongest predictors of mortality in patients with ESRD.

To see if training could counteract the process of muscle wasting, the investigators designed the Progressive Exercise for Anabolism in Kidney Disease (PEAK) trial. The 49 participants were patients undergoing dialysis at an outpatient hemodialysis unit, and were randomly assigned to the exercise program or to a usual-care control group.

The exercises were performed while patients were seated or supine. Each session included two sets of eight repetitions of ten exercises, using free-weight dumbbells for the upper body, and weighted ankle cuffs for the lower body.

After 12 weeks, CT scans showed that the weight-training group had significantly less intramuscular lipid infiltration, a marker of muscle quality (p = 0.04).

The cross-sectional measure of thigh mass was higher in the exercise group, and worse in the controls, but the difference between the two was not statistically significant. Still, Dr. Cheema's group maintains that the difference is clinically important.

Improvements in several secondary outcomes -- total body strength, body mass index, and C-reactive protein -- were significantly greater among those who lifted weights. The intervention group also improved in two of eight quality-of-life domains, Physical Function and Vitality.

Dr. Cheema and his team observed no significant differences in dialysis-related complaints. The only adverse event occurred in a 73-year-old woman -- a partial tearing of a supraspinatus muscle -- which was treated conservatively and had no effect on her ability to continue lifting weights.

The investigators conclude, "Intradialytic progressive resistance training may provide a simple, practical method by which the health status of this cohort can be improved."