The effect of minimal exercise on the blood lactate in azotemic subjects

Forty-one subjects, including 16 non-azotemic and 25 azotemic individuals, were studied during minimal exercise walking on a treadmill. Blood lactate levels rose dramatically in those with renal failure (maximum 2.05 +/- 1.22 mM/l above resting levels) but not in those who were not azotemic (0.25 +/- 0.22 mM/l above resting levels). Blood lactate/pyruvate ratios also increased in azotemic subjects (from 11.2 at rest to 21.0 after 10 minutes of minimal activity) as compared with non-azotemic controls (from 10.9 at rest to 9.8 after 10 minutes of minimal exercise). These findings suggest an abnormality in the muscle handling of lactate during exercise in individuals with renal failure. The abnormality may pose a problem in the rehabilitation of individuals with renal failure.