Department of Senior Welfare and Services, Southern Taiwan University of Science and Technology, No. 1, Nan-Tai Street, Yungkang District, Tainan 710301, Taiwan.
Office of Student Affairs, Tainan City Siaying Elementary School, No. 72, Sect. 2, Jhongshan Rd., Siaying District, Tainan 73541, Taiwan.
Int J Environ Res Public Health. 2022 Nov 23;19(23):15502. doi: 10.3390/ijerph192315502.
The effects of fasting and different exercise intensities on lipid metabolism were investigated in 12 male students aged 19.9 ± 1.4 years, with maximal oxygen consumption (VO) of 50.33 ± 4.0 mL/kg/min, using a counterbalanced design. Each participant ran on a treadmill at 45% and 65% VO continuously for 20 min, followed by running at 85% VO for 20 min (or until exhaustion) under a fed or fasted state (6 h). The respiratory exchange ratio (RER), blood glucose (BGLU), blood lactate (BLA), and blood triglyceride (TG) were analyzed during exercise. The results showed that the intensity of exercise did not significantly affect the BGLU and TG in the fed state. The levels of both RER and BLA increased as the intensity of exercise increased from low to high (45, 65, and 85% VO), and more energy was converted from fat into glucose at a high intensity of exercise. In the fasted state of 6 h, the BGLU level increased parallel to the intensity of exercise. The RER was close to 1.0 at a high intensity of exercise, indicating that more energy was converted from glycogen. At the intensities of 45 and 65% VO, the RER and concentration of TG were both lower in the fasted than in the fed state, showing that a higher percentage of energy comes from fat than in the fed state at 45 and 65% VO. When running at 85% VO, the BGLU concentration was higher in the fasted than in the fed state, indicating that the liver tissues release more BGLU for energy in the fasted state. Therefore, in the fasted state, running at 45% and 65% of VO significantly affects lipid metabolism. On the contrary, the higher RER and BGLU concentrations when running at 85% VO revealed no significant difference between the two probes. This study suggests that medium- and low-intensity exercise (45 and 65% VO) in the fasted state enhances lipid metabolism.
本研究旨在探讨禁食和不同运动强度对 12 名 19.9 ± 1.4 岁男性大学生脂质代谢的影响。这些男性的最大摄氧量（VO）为 50.33 ± 4.0 mL/kg/min，采用平衡设计，让他们分别在禁食或进食状态下，以 45%和 65%VO 持续跑步 20 分钟，随后以 85%VO 跑步 20 分钟（或直至力竭）。在运动过程中分析呼吸交换率（RER）、血糖（BGLU）、血乳酸（BLA）和血甘油三酯（TG）。结果表明，在进食状态下，运动强度对 BGLU 和 TG 无显著影响。随着运动强度从低到高（45%、65%和 85%VO）的增加，RER 和 BLA 水平均升高，高强度运动时更多的能量由脂肪转化为葡萄糖。在禁食 6 小时的状态下，BGLU 水平随运动强度的增加而平行升高。高强度运动时，RER 接近 1.0，表明更多的能量来自糖原。在 45%和 65%VO 的强度下，禁食状态下的 RER 和 TG 浓度均低于进食状态，表明在 45%和 65%VO 时，禁食状态下更多的能量来自脂肪。当以 85%VO 跑步时，禁食状态下的 BGLU 浓度高于进食状态，表明在禁食状态下，肝脏组织释放更多的 BGLU 供能。因此，在禁食状态下，以 45%和 65%VO 进行的中低强度运动显著影响脂质代谢。相反，在以 85%VO 跑步时更高的 RER 和 BGLU 浓度表明两种探针之间没有显著差异。本研究表明，禁食状态下的中低强度运动（45%和 65%VO）可增强脂质代谢。
