Çukurova University, Medical Faculty, Department of Physiology, Division of Sports Physiology, Adana, Turkey.
Department of Physical Education and Sports, Adana, Turkey.
J Sports Sci Med. 2019 Feb 11;18(1):44-51. eCollection 2019 Mar.
This study aimed to compare the maximal fat oxidation (MFO) rates obtained from the stage average, last 2 min average, and highest value in the Fatmax stage determined with a 6 min step protocol. A total of 35 overweight, sedentary healthy men (age: 25.4 ± 0.7 years, body mass index: 26.0 ± 0.6 kg/m) participated in the study. Substrate oxidation was calculated using breath-by-breath gas exchange data for each stage. When the change in the fat oxidation rate for every min throughout the Fatmax stage was evaluated, the average value of the 4 min was significantly lower than that of the 2 and 3 min (p < 0.01). In addition, the 5 and 6 min fat oxidation rates were significantly lower than the rates of the 1, 2, 3, and 4 min (0.30 ± 0.01 and 0.29 ± 0.01 g/min for the 5 and 6 min, respectively, vs. 0.35 ± 0.02, 0.34 ± 0.02, 0.33 ± 0.02, and 0.31 ± 0.01 g/min for the 1, 2, 3, and 4 min, respectively; p < 0.01). Most of the participants had MFO rates in the 1 min of the stage (16/35 participants), and the MFO rates of the remaining participants were observed in the 2, 3, and 4 min (7/35, 4/35, and 8/35 participants, respectively). None of the participants had MFO rates in the 5 or 6 min. The individual MFO rate (highest fat oxidation rate during Fatmax) was significantly higher than the fat oxidation rate calculated with the last 2 min average values (0.36 ± 0.02 and 0.30 ± 0.01 g/min, respectively; p < 0.05). In conclusion, the calculation of the fat oxidation rate by averaging the last portion of the Fatmax stage data may cause the underestimation of the MFO rate, which probably occurs earlier in the Fatmax stage.
本研究旨在比较 6 分钟递增负荷试验中通过阶段平均、最后 2 分钟平均和 Fatmax 阶段最高值所获得的最大脂肪氧化率（MFO）。共有 35 名超重、久坐的健康男性（年龄：25.4 ± 0.7 岁，BMI：26.0 ± 0.6 kg/m）参与了这项研究。在每个阶段，使用呼吸交换数据计算底物氧化。当评估 Fatmax 阶段内每分钟脂肪氧化率的变化时，4 分钟的平均值明显低于 2 分钟和 3 分钟（p < 0.01）。此外，5 分钟和 6 分钟的脂肪氧化率明显低于 1、2、3 和 4 分钟的脂肪氧化率（5 分钟和 6 分钟分别为 0.30 ± 0.01 和 0.29 ± 0.01 g/min，而 1、2、3 和 4 分钟分别为 0.35 ± 0.02、0.34 ± 0.02、0.33 ± 0.02 和 0.31 ± 0.01 g/min；p < 0.01）。大多数参与者的 MFO 率出现在阶段的 1 分钟（35 名参与者中的 16 名），其余参与者的 MFO 率出现在 2、3 和 4 分钟（35 名参与者中的 7 名、4 名和 8 名）。没有参与者的 MFO 率出现在 5 分钟或 6 分钟。个体 MFO 率（Fatmax 期间的最高脂肪氧化率）明显高于用最后 2 分钟平均值计算得出的脂肪氧化率（0.36 ± 0.02 和 0.30 ± 0.01 g/min；p < 0.05）。综上所述，通过平均 Fatmax 阶段最后一部分的数据来计算脂肪氧化率可能会导致对 MFO 率的低估，这种低估可能发生在 Fatmax 阶段的早期。
