Improved reliability of the urine lactate concentration under controlled hydration after maximal exercise.

CONTEXT: Urine lactate may be a novel biomarker of lactate production capacity but its reliability has been unsatisfactory so far. OBJECTIVE: To compare the reliability of urine lactate between controlled hydration and no hydration after maximal exercise. MATERIAL AND METHODS: Athletes performed swimming exercise four times: two followed by consumption of 1 L of water and two followed by no water intake. Blood and urine lactate was measured. RESULTS: The reliability of urine lactate was good and similar to that in blood only after controlled hydration. Blood and urine lactate were correlated under both hydration conditions. DISCUSSION AND CONCLUSION: Controlled hydration after exercise provides satisfactory reliability of urine lactate.