Renal responses to bicycle exercise in trained athletes: influence of exercise intensity.

The effects of exercise on renal function were studied in 11 male bicyclists, using a bicycle ergometer. At a work intensity of 100/150 W, bicycle exercise for 1 h was associated with a significant increase in urine volume, endogenous creatinine clearance, and renal sodium and potassium excretion. In contrast, exercise of the same duration at a work intensity of 150/200 W produced no significant changes in the above variables. Exercise intensity seems to influence renal responses, presumably through a differential effect on renal blood flow.