Aslankeser Zübeyde, Balcı Şükrü Serdar
Faculty of Sports Science, Selçuk University, Konya, Turkey.
PeerJ. 2017 Sep 6;5:e3769. doi: 10.7717/peerj.3769. eCollection 2017.
It has been believed that the contribution of fat oxidation to total energy expenditure is becoming negligible at higher exercise intensities (about 85% VO). The aim of the present study was to examine the changes in substrate oxidation during high-intensity interval exercise in young adult men.
A total of 18 healthy well-trained (aged 19.60 ± 0.54 years, BMI = 22.19 ± 0.64 kg/m, = 10) and untrained (aged 20.25 ± 0.41 years, BMI = 22.78 ± 0.38 kg/m, = 8) young men volunteered to participate in this study. After an overnight fast, subjects were tested on a cycle ergometer and completed six 4-min bouts of cycling (at ∼80% VO) with 2 min of rests between intervals. Energy expenditure and the substrate oxidation rate were measured during the experiment by using indirect calorimetry. The blood lactate concentration was collected immediately after each interval workout.
The fat oxidation rate during each workout was significantly different between the untrained and the athlete groups ( < 0.05), and the carbohydrate (CHO) oxidation rate during the experiment was similar between groups ( > 0.05). Moreover, lactate concentration significantly increased in the untrained group ( < 0.05), whereas it did not significantly change in the athlete group during the workouts ( > 0.05). Fat contribution to energy expenditure was significantly higher in the athlete group (∼25%) than in the untrained group (∼2%).
The present study indicates that 17 times more fat oxidation was measured in the athlete group compared to the untrained group. However, the athletes had the same CHO oxidation rate as the recreationally active subjects during high-intensity intermittent exercise. Higher fat oxidation rate despite the same CHO oxidation rate may be related to higher performance in the trained group.
人们一直认为，在较高运动强度（约85%最大摄氧量）下，脂肪氧化对总能量消耗的贡献变得微不足道。本研究的目的是研究年轻成年男性在高强度间歇运动期间底物氧化的变化。
共有18名健康的受过良好训练的年轻男性（年龄19.60±0.54岁，体重指数=22.19±0.64kg/m²，n=10）和未受过训练的年轻男性（年龄20.25±0.41岁，体重指数=22.78±0.38kg/m²，n=8）自愿参加本研究。在禁食过夜后，受试者在自行车测力计上进行测试，并完成六组4分钟的骑行（约80%最大摄氧量），组间休息2分钟。在实验过程中，使用间接测热法测量能量消耗和底物氧化率。每次间歇训练后立即采集血乳酸浓度。
未受过训练的组和运动员组在每次训练期间的脂肪氧化率存在显著差异（P<0.05），且实验期间两组间的碳水化合物（CHO）氧化率相似（P>0.05）。此外，未受过训练的组中乳酸浓度显著增加（P<0.05），而在训练期间运动员组中乳酸浓度没有显著变化（P>0.05）。运动员组中脂肪对能量消耗的贡献（约25%）显著高于未受过训练的组（约2%）。
本研究表明，与未受过训练的组相比，运动员组的脂肪氧化量是其17倍。然而，在高强度间歇运动期间，运动员的CHO氧化率与有规律运动的受试者相同。尽管CHO氧化率相同，但较高的脂肪氧化率可能与训练组的较高运动表现有关。
