The effects of exercise on markers of lipid peroxidation in renal dialysis patients compared with control subjects.

Purpose: The purpose of this study was to compare the susceptibility to exercise-induced lipid peroxidation of patients on chronic maintenance dialysis (CMD) and non-CMD control subjects.

Design: Cross-sectional comparison of exercise-induced changes in breath ethane and pentane flux between patients on CMD (group A) and an age-, gender-, medical diagnosis-, smoking-, and ethanol consumption-matched comparison group (group B). Breath ethane and pentane were measured at rest before exercise, during cardiopulmonary exercise stress testing (CPX) at lactic acidosis threshold (Vo2lat), and 5 minutes after CPX.

Results: Group comparisons of clinical characteristics reveal that the groups were similar in terms of age, ethnicity, comorbid diagnoses, prevalence of medication use, BMI, measurements of aerobic exercise capacity, cigarette smoking and ethanol consumption behaviors. All subjects successfully completed the CPX protocol achieving Vo2lat. There were significant differences in breath ethane flux between group A and B subjects, with greater pre-exercise, Vo2lat, and postexercise ethane levels in group A compared with group B subjects, and significant group differences, with lower breath ethane/pentane flux ratios at rest, Vo2lat, and recovery with lower ratios in group B than group A subjects.

Discussion/conclusions: This study shows that patients on CMD have greater lipid peroxidation compared with control subjects at rest and during and after physical exercise. In addition, compared with control subjects, patients on CMD preferentially peroxidize n-3 polyunsaturated fatty acids at rest and during physical exercise and recovery. The lipid peroxidation profile may result in an unfavorable endoperoxide shift and should be evaluated further, along with modalities to reduce oxidative stress among patients on CMD.