Aughey R J, Gore C J, Hahn A G, Garnham A P, Clark S A, Petersen A C, Roberts A D, McKenna M J
School of Human Movement, Recreation and Performance (FO22) Victoria University of Technology, P.O. Box 14428, MCMC, Melbourne, Victoria 8001, Australia.
J Appl Physiol (1985). 2005 Jan;98(1):186-92. doi: 10.1152/japplphysiol.01335.2003. Epub 2004 Mar 19.
Athletes commonly attempt to enhance performance by training in normoxia but sleeping in hypoxia [live high and train low (LHTL)]. However, chronic hypoxia reduces muscle Na(+)-K(+)-ATPase content, whereas fatiguing contractions reduce Na(+)-K(+)-ATPase activity, which each may impair performance. We examined whether LHTL and intense exercise would decrease muscle Na(+)-K(+)-ATPase activity and whether these effects would be additive and sufficient to impair performance or plasma K(+) regulation. Thirteen subjects were randomly assigned to two fitness-matched groups, LHTL (n = 6) or control (Con, n = 7). LHTL slept at simulated moderate altitude (3,000 m, inspired O(2) fraction = 15.48%) for 23 nights and lived and trained by day under normoxic conditions in Canberra (altitude approximately 600 m). Con lived, trained, and slept in normoxia. A standardized incremental exercise test was conducted before and after LHTL. A vastus lateralis muscle biopsy was taken at rest and after exercise, before and after LHTL or Con, and analyzed for maximal Na(+)-K(+)-ATPase activity [K(+)-stimulated 3-O-methylfluorescein phosphatase (3-O-MFPase)] and Na(+)-K(+)-ATPase content ([(3)H]ouabain binding sites). 3-O-MFPase activity was decreased by -2.9 +/- 2.6% in LHTL (P < 0.05) and was depressed immediately after exercise (P < 0.05) similarly in Con and LHTL (-13.0 +/- 3.2 and -11.8 +/- 1.5%, respectively). Plasma K(+) concentration during exercise was unchanged by LHTL; [(3)H]ouabain binding was unchanged with LHTL or exercise. Peak oxygen consumption was reduced in LHTL (P < 0.05) but not in Con, whereas exercise work was unchanged in either group. Thus LHTL had a minor effect on, and incremental exercise reduced, Na(+)-K(+)-ATPase activity. However, the small LHTL-induced depression of 3-O-MFPase activity was insufficient to adversely affect either K(+) regulation or total work performed.
运动员通常试图通过在常氧环境中训练但在低氧环境中睡眠来提高成绩[高住低练（LHTL）]。然而，慢性低氧会降低肌肉钠钾ATP酶含量，而疲劳性收缩会降低钠钾ATP酶活性，这两者都可能损害运动表现。我们研究了高住低练和高强度运动是否会降低肌肉钠钾ATP酶活性，以及这些影响是否会叠加并足以损害运动表现或血浆钾调节。13名受试者被随机分为两个健康状况匹配的组，高住低练组（n = 6）或对照组（Con，n = 7）。高住低练组在模拟中度海拔（3000米，吸入氧分数 = 15.48%）睡眠23晚，白天在堪培拉的常氧环境中生活和训练（海拔约600米）。对照组在常氧环境中生活、训练和睡眠。在高住低练前后进行标准化递增运动测试。在高住低练组或对照组前后，休息时和运动后取股外侧肌活检样本，分析钠钾ATP酶最大活性[钾刺激的3 - O - 甲基荧光素磷酸酶（3 - O - MFPase）]和钠钾ATP酶含量（[³H]哇巴因结合位点）。高住低练组中3 - O - MFPase活性降低了 - 2.9±2.6%（P < 0.05），运动后立即降低（P < 0.05），对照组和高住低练组情况类似（分别为 - 13.0±3.2%和 - 11.8±1.5%）。高住低练组运动期间血浆钾浓度未改变；[³H]哇巴因结合在高住低练组或运动后未改变。高住低练组峰值耗氧量降低（P < 0.05），而对照组未降低，两组运动做功均未改变。因此，高住低练对钠钾ATP酶活性有轻微影响，递增运动可降低其活性。然而，高住低练引起的3 - O - MFPase活性的轻微降低不足以对钾调节或总做功产生不利影响。
