LFE Research Group, Department of Health and Human Performance, Faculty of Physical Activity and Sport Science (INEF), Universidad Politécnica de Madrid, Madrid, Spain.
Olympia Sport & Lifestyle Center, Grupo Quironsalud, Madrid, Spain.
Eur J Sport Sci. 2024 Nov;24(11):1653-1663. doi: 10.1002/ejsc.12211. Epub 2024 Oct 30.
It is unknown whether changes in lactate concentration produced by different situations (e.g., glycogen depletion or heat) modify fat oxidation. If confirmed, we could determine a dose-response relationship between lactate and fat. The aim of this study was to determine whether changes in lactate concentration (due to glycogen depletion or heat) alter fat oxidation during exercise. 11 males and eight females performed an incremental exercise test under three situations: control, glycogen depletion, and heat. At rest, in the last minute of each step and immediately post-exhaustion, lactate was analyzed and fat oxidation was estimated by indirect calorimetry. Lactate concentration was inversely associated with fat oxidation in the three aforementioned situations (r > 0.88 and p < 0.05). The highest lactate concentration was found in the heat situation, followed by the control situation, and finally the glycogen depletion situation (all p < 0.05). The opposite was found for fat oxidation, with the highest fat oxidation found in the glycogen depletion situation, followed by the control situation, and finally the heat situation (all p < 0.05). There is no association between the changes in lactate concentration between situations at each intensity and the changes in fat oxidation between situations at each intensity in males or females (p > 0.05). In conclusion, lactatemia is strongly and inversely associated with fat oxidation under the three different situations. Furthermore, the lowest lactate concentrations were accompanied by the highest fat oxidations in the glycogen depletion situation, whereas the highest lactate concentrations were accompanied by the lowest fat oxidations in the heat situation.
目前尚不清楚不同情况下（例如糖原耗竭或热量）产生的乳酸浓度变化是否会改变脂肪氧化。如果得到证实，我们可以确定乳酸和脂肪之间的剂量-反应关系。本研究旨在确定乳酸浓度（由于糖原耗竭或热量）的变化是否会改变运动过程中的脂肪氧化。11 名男性和 8 名女性在三种情况下进行了递增运动测试：对照、糖原耗竭和热。在休息时、每一步的最后一分钟和运动结束后立即，分析了乳酸并通过间接测热法估计了脂肪氧化。在上述三种情况下，乳酸浓度与脂肪氧化呈负相关（r>0.88，p<0.05）。在热情况下发现的乳酸浓度最高，其次是对照情况，最后是糖原耗竭情况（均为 p<0.05）。对于脂肪氧化则发现相反的情况，糖原耗竭情况下的脂肪氧化最高，其次是对照情况，最后是热情况（均为 p<0.05）。在男性或女性中，各强度下的三种情况之间的乳酸浓度变化与各强度下的三种情况之间的脂肪氧化变化之间没有关联（p>0.05）。总之，在三种不同情况下，乳酸性血症与脂肪氧化呈强烈的负相关。此外，在糖原耗竭情况下，乳酸浓度最低，脂肪氧化最高，而在热情况下，乳酸浓度最高，脂肪氧化最低。
