Ashenden M J, Gore C J, Dobson G P, Boston T T, Parisotto R, Emslie K R, Trout G J, Hahn A G
Department of Physiology and Applied Nutrition, Australian Institute of Sport, Belconnen, Canberra.
Eur J Appl Physiol. 2000 Mar;81(5):428-35. doi: 10.1007/s004210050064.
The purpose of this study was to investigate whether the modest increases in serum erythropoietin (sEpo) experienced after brief sojourns at simulated altitude are sufficient to stimulate reticulocyte production. Six well-trained middle-distance runners (HIGH, mean maximum oxygen uptake, VO2max = 70.2 ml x kg(-1) x min(-1) spent 8-11 h per night for 5 nights in a nitrogen house that simulated an altitude of 2650 m. Five squad members (CONTROL, mean VO2max= 68.9 ml x kg(-1) x min(-1) undertook the same training, which was conducted under near-sea-level conditions (600 m altitude), and slept in dormitory-style accommodation also at 600 m altitude. For both groups, this 5-night protocol was undertaken on three occasions, with a 3-night interim between successive exposures. Venous blood samples were measured for sEpo after 1 and 5 nights of hypoxia on each occasion. The percentage of reticulocytes was measured, along with a range of reticulocyte parameters that are sensitive to changes in erythropoiesis. Mean serum erythropoietin levels increased significantly (P < 0.01) above baseline values [mean (SD) 7.9 (2.4) mU x ml(-1)] in the HIGH group after the 1st night [11.8 (1.9) mU x ml(-1), 57%], and were also higher on the 5th night [10.7 (2.2) mU x ml(-1), 42%] compared with the CONTROL group, whose erythropoietin levels did not change. After athletes spent 3 nights at near sea level, the change in sEpo during subsequent hypoxic exposures was markedly attenuated (13% and -4% change during the second exposure; 26% and 14% change during the third exposure; 1st and 5th nights of each block, respectively). The increase in sEpo was insufficient to stimulate reticulocyte production at any time point. We conclude that when daily training loads are controlled, the modest increases in sEpo known to occur following brief exposure to a simulated altitude of 2650 m are insufficient to stimulate reticulocyte production.
本研究的目的是调查在模拟海拔短暂停留后血清促红细胞生成素（sEpo）的适度增加是否足以刺激网织红细胞生成。六名训练有素的中长跑运动员（高海拔组，平均最大摄氧量，VO2max = 70.2 ml x kg(-1) x min(-1)）在模拟海拔2650米的氮气舱中每晚花费8 - 11小时，共5晚。五名队员（对照组，平均VO2max = 68.9 ml x kg(-1) x min(-1)）进行相同的训练，训练在近海平面条件（海拔600米）下进行，且也在海拔600米的宿舍式住所睡觉。两组均三次进行这一为期5晚的方案，连续暴露之间有3晚的间隔期。每次在缺氧1晚和5晚后采集静脉血样本测量sEpo。测量网织红细胞百分比以及一系列对红细胞生成变化敏感的网织红细胞参数。高海拔组在第1晚后血清促红细胞生成素水平显著高于基线值（P < 0.01）[平均（标准差）7.9（2.4）mU x ml(-1)升至11.8（1.9）mU x ml(-1)，升高57%]，且在第5晚[10.7（2.2）mU x ml(-1)，升高42%]时也高于对照组，而对照组促红细胞生成素水平未变化。运动员在近海平面度过3晚后，随后缺氧暴露期间sEpo的变化明显减弱（第二次暴露期间变化13%和 - 4%；第三次暴露期间变化26%和14%；分别为每个阶段的第1晚和第5晚）。sEpo的增加在任何时间点都不足以刺激网织红细胞生成。我们得出结论，当每日训练负荷得到控制时，短暂暴露于模拟海拔2650米后已知会出现的sEpo适度增加不足以刺激网织红细胞生成。
