Renal lactate elimination is maintained during moderate exercise in humans

Abstract

Reduced hepatic lactate elimination initiates blood lactate accumulation during incremental exercise. In this study, we wished to determine whether renal lactate elimination contributes to the initiation of blood lactate accumulation. The renal arterial-to-venous (a-v) lactate difference was determined in nine men during sodium lactate infusion to enhance the evaluation (0.5 mol x L(-1) at 16 ± 1 mL x min(-1); mean ± s) both at rest and during cycling exercise (heart rate 139 ± 5 beats x min(-1)). The renal release of erythropoietin was used to detect kidney tissue ischaemia. At rest, the a-v O(2) (CaO(2)-CvO(2)) and lactate concentration differences were 0.8 ± 0.2 and 0.02 ± 0.02 mmol x L(-1), respectively. During exercise, arterial lactate and CaO(2)-CvO(2) increased to 7.1 ± 1.1 and 2.6 ± 0.8 mmol x L(-1), respectively (P < 0.05), indicating a -70% reduction of renal blood flow with no significant change in the renal venous erythropoietin concentration (0.8 ± 1.4 U x L(-1)). The a-v lactate concentration difference increased to 0.5 ± 0.8 mmol x L(-1), indicating similar lactate elimination as at rest. In conclusion, a -70% reduction in renal blood flow does not provoke critical renal ischaemia, and renal lactate elimination is maintained. Thus, kidney lactate elimination is unlikely to contribute to the initial blood lactate accumulation during progressive exercise.

The role of lactate in sepsis and COVID‐19: Perspective from contracting skeletal muscle metabolism

“…1B). In contrast, the kidneys appear to maintain lactate uptake during incremental exercise, despite reduced renal blood flow (Volianitis et al, 2012).…”

“…Thus, the exponential increase in blood lactate with work intensity does not represent an ‘anaerobic threshold’ (Wasserman, 1987), but rather reflects collapse of liver sinusoids because of inadequate blood flow, meaning that less liver tissue is available for lactate elimination (Figure 1b). In contrast, the kidneys appear to maintain lactate uptake during incremental exercise, despite reduced renal blood flow (Volianitis et al., 2012).…”

Cardiovascular control during whole body exercise

“…The data confirm across exercise modalities a twofold higher muscle DO2 in the legs compared with the arms. the reduction in venous oxygenation (213). Considering that splanchnic and renal circulations, combined with the modest vasoconstriction in inactive skeletal muscles, can contribute to the systemic circulation at most a total of ϳ1 l/min (164), it is deemed that active muscles are needed as a circulatory "donor" (78).…”