College of Health and Biomedicine, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
Eur J Appl Physiol. 2014;114(7):1513-20. doi: 10.1007/s00421-014-2878-x. Epub 2014 Apr 19.
Exercise at 50-60 % of peak oxygen consumption (VO2 peak) stimulates maximal fat oxidation rates. Despite a lower estimated work performed; high-intensity intermittent exercise (HIIE) training produces greater fat mass reductions when compared with workload-matched continuous (CON) steady state exercise. No metabolic basis has been documented nor mechanisms offered to explain this anomaly. This study investigated the physiological and metabolic responses of two different workload-matched exercise protocols.
On separate occasions and at least 1 week apart, eight apparently healthy males cycled for 30 min at either 50 % VO2 peak (CON) or performed repeated 20 s bouts of supramaximal exercise at 150 %VO2 peak separated by 40 s rest (HIIE).
The average heart rate, oxygen consumption, plasma glycerol and free fatty acid concentrations were not different during exercise and recovery between the trials. Plasma lactate and hypoxanthine (Hx) concentrations were elevated and urinary excretion rates of Hx and uric acid were greater following HIIE as compared to CON (P < 0.05).
Exercise-induced plasma Hx accumulation and urinary purine excretion are greater following HIIE and indirectly represents a net loss of adenosine triphosphate (ATP) from the muscle. The subsequent restorative processes required for intramuscular de novo replacement of ATP may contribute to a negative energy balance and in part, account for the potential accelerated fat loss observed with HIIE when compared with CON training programs.
以 50-60%的峰值耗氧量（VO2 峰值）进行运动可刺激最大脂肪氧化速率。尽管估计的工作量较低，但与工作量匹配的连续（CON）稳态运动相比，高强度间歇运动（HIIE）训练可更大程度地减少脂肪量。尚未记录到代谢基础，也没有提出机制来解释这种异常现象。本研究调查了两种不同工作量匹配的运动方案的生理和代谢反应。
在不同的时间点，且至少相隔 1 周，8 名健康男性分别以 50%VO2 峰值（CON）或 150%VO2 峰值进行重复 20 秒的超最大运动，其间间隔 40 秒休息，进行 30 分钟的骑行。
在两次试验中，运动和恢复期间的平均心率、耗氧量、血浆甘油和游离脂肪酸浓度没有差异。与 CON 相比，HIIE 后血浆乳酸和次黄嘌呤（Hx）浓度升高，Hx 和尿酸的尿排泄率更高（P<0.05）。
与 CON 相比，HIIE 后运动诱导的血浆 Hx 积累和尿嘌呤排泄增加，间接代表肌肉中三磷酸腺苷（ATP）的净损失。随后肌肉内新合成 ATP 的恢复过程可能导致负能平衡，并在一定程度上解释了与 CON 训练计划相比，HIIE 观察到的潜在加速脂肪损失的原因。
