Research Centre for Exercise and Health, Department of Biomedical Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium.
J Appl Physiol (1985). 2011 Jul;111(1):108-16. doi: 10.1152/japplphysiol.01459.2010. Epub 2011 May 5.
In this study, we compared the effects of endurance training in the fasted state (F) vs. the fed state [ample carbohydrate intake (CHO)] on exercise-induced intramyocellular lipid (IMCL) and glycogen utilization during a 6-wk period of a hypercaloric (∼+30% kcal/day) fat-rich diet (HFD; 50% of kcal). Healthy male volunteers (18-25 yrs) received a HFD in conjunction with endurance training (four times, 60-90 min/wk) either in F (n = 10) or with CHO before and during exercise sessions (n = 10). The control group (n = 7) received a HFD without training and increased body weight by ∼3 kg (P < 0.001). Before and after a HFD, the subjects performed a 2-h constant-load bicycle exercise test in F at ∼70% maximal oxygen uptake rate. A HFD, both in the absence (F) or presence (CHO) of training, elevated basal IMCL content by ∼50% in type I and by ∼75% in type IIa fibers (P < 0.05). Independent of training in F or CHO, a HFD, as such, stimulated exercise-induced net IMCL breakdown by approximately twofold in type I and by approximately fourfold in type IIa fibers. Furthermore, exercise-induced net muscle glycogen breakdown was not significantly affected by a HFD. It is concluded that a HFD stimulates net IMCL degradation by increasing basal IMCL content during exercise in type I and especially IIa fibers. Furthermore, a hypercaloric HFD provides adequate amounts of carbohydrates to maintain high muscle glycogen content during training and does not impair exercise-induced muscle glycogen breakdown.
在这项研究中，我们比较了空腹（F）和进食状态[充足碳水化合物摄入（CHO）]下的耐力训练对高脂肪饮食（HFD；卡路里的 50%）6 周期间运动引起的肌内细胞脂质（IMCL）和糖原利用的影响。健康男性志愿者（18-25 岁）在接受 HFD 的同时进行耐力训练（四次，每周 60-90 分钟），要么在 F 中进行（n=10），要么在运动期间进食 CHO（n=10）。对照组（n=7）接受 HFD 但不进行训练，体重增加约 3 公斤（P<0.001）。在 HFD 前后，受试者在 F 下进行 2 小时恒负荷自行车运动测试，达到最大摄氧量的约 70%。HFD 无论是否存在训练（F 或 CHO），都会使 I 型和 IIa 型纤维的基础 IMCL 含量分别增加约 50%和 75%（P<0.05）。独立于 F 或 CHO 中的训练，HFD 本身会刺激 I 型和 IIa 型纤维中运动引起的净 IMCL 分解增加约两倍和四倍。此外，HFD 不会显著影响运动引起的肌肉糖原分解。因此，HFD 通过增加运动时 I 型和 IIa 型纤维中的基础 IMCL 含量来刺激净 IMCL 降解。此外，高卡路里的 HFD 在训练期间提供足够的碳水化合物来维持高肌肉糖原含量，并且不会损害运动引起的肌肉糖原分解。
