Exogenous lactate intake immediately after endurance exercise increases time to exhaustion in VO(2max) measurements in mice

[PURPOSE]: The purpose of the study was to investigate the effects of 4 weeks of lactate intake immediately after endurance exercise on maximal oxygen uptake (VO(2max)) in exercise performance. [METHODS]: Seven-week-old mice from the Institute of Cancer Research (ICR) were randomly divided into four groups: vehicle intake (SE/CON), lactate intake (SE/LAC), endurance exercise with vehicle intake (EX/ CON), and lactate intake with endurance exercise (EX/ LAC). Mice were subjected to 60-70% VO(2max) endurance exercise with or without oral lactate intake 5 days/ week for 4 weeks. VO(2max) measurements (VO(2max), time to exhaustion (TTE), respiratory exchange rate, fat oxidation, and carbohydrate oxidation) were recorded at the end of the study period. After 48 h of VO(2max) measurement, the mice were sacrificed, and three different abdominal fat samples (epididymal, perirenal, and mesenteric) were collected. [RESULTS]: Body weight and abdominal fat mass did not differ between the groups. When measuring VO(2max), endurance exercise raised VO(2max), and lactate intake after endurance exercise increased TTE. The change in energy substrate utilization during VO(2max) measurement demonstrated that although the respiratory exchange rate and fat oxidation were enhanced by lactate intake, there were no synergistic effects of lactate intake and endurance exercise. [CONCLUSION]: Lactate intake immediately after endurance exercises can improve exercise performance, indicating the benefit of long-term exogenous lactate intake as an exercise supplement.