Beidleman B A, Muza S R, Rock P B, Fulco C S, Lyons T P, Hoyt R W, Cymerman A
Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 07160, USA.
Med Sci Sports Exerc. 1997 Dec;29(12):1588-95. doi: 10.1097/00005768-199712000-00007.
Following 2 to 3 wk of altitude acclimatization, ventilation is increased and heart rate (HR), plasma volume (PV), and lactate accumulation ([La]) are decreased during submaximal exercise. The objective of this study was to determine whether some degree of these exercise responses associated with acclimatization would be retained upon reintroduction to altitude (RA) after 8 d at sea level (SL). Six male lowlanders (X +/- SE; 31 +/- 2 yr, 82.4 +/- 4.6 kg) exercised to exhaustion at the same relative percentages of peak oxygen uptake (VO2peak) at SL, on acute altitude (AA) exposure, after a 16-d chronic altitude (CA) exposure on Pikes Peak (4,300 m), and during a 3- to 4-h RA in a hypobaric chamber (4,300 m; 446 mm Hg) after 8 d at SL. The submaximal exercise to exhaustion time (min) was the same at SL (66.0 +/- 1.6), AA (67.7 +/- 7.3), CA (79.9 +/- 6.2), and RA (67.9 +/- 1.9). At 75% VO2peak: (1) arterial oxygen saturation (SaO2) increased from AA to CA (67.0 +/- 1.5 vs 78.5 +/- 1.8%; P < 0.05) and remained increased at RA (77.0 +/- 2.0%); (2) HR decreased from SL to CA (171 +/- 6 vs 152 +/- 9 beats x min-1; P < 0.05) and remained decreased at RA (157 +/- 5 beats x min-1); (3) calculated PV decreased 6.9 +/- 10.0% at AA, 21.3 +/- 11.1% at CA, and 16.7 +/- 5.4% at RA from SL baseline values, and (4) [La] decreased from AA to CA (5.1 +/- 0.9 vs 1.9 +/- 0.4 mmol x L-1; P < 0.05) and remained decreased at RA (2.6 +/- 0.6 mmol x L-1). Upon RA after 8 d at SL, the acclimatization responses were retained 92 +/- 9% for SaO2, 74 +/- 8% for PV, and 58 +/- 3% for [La] at 75% VO2peak. In conclusion, although submaximal exercise to exhaustion time is not improved upon reintroduction to altitude after 8 d at sea level, retention of beneficial exercise responses associated with altitude acclimatization is likely in individuals whose work, athletic competition, or recreation schedules involve intermittent sojourns to high elevations.
在进行2至3周的高原适应后，进行次最大运动时，通气增加，心率（HR）、血浆容量（PV）和乳酸积累（[La]）减少。本研究的目的是确定在海平面（SL）停留8天后重新进入高原（RA）时，与适应相关的这些运动反应的某种程度是否会保留。六名男性低landers（X +/- SE；31 +/- 2岁，82.4 +/- 4.6千克）在SL、急性高原（AA）暴露时、在派克峰（4300米）进行16天慢性高原（CA）暴露后以及在SL停留8天后在低压舱（4300米；446毫米汞柱）进行3至4小时RA期间，以相同的相对峰值摄氧量（VO2peak）百分比运动至 exhaustion。次最大运动至 exhaustion时间（分钟）在SL（66.0 +/- 1.6）、AA（67.7 +/- 7.3）、CA（79.9 +/- 6.2）和RA（67.9 +/- 1.9）时相同。在75%VO2peak时：（1）动脉血氧饱和度（SaO2）从AA增加到CA（67.0 +/- 1.5对78.5 +/- 1.8%；P < 0.05），在RA时保持增加（77.0 +/- 2.0%）；（2）HR从SL降低到CA（171 +/- 6对152 +/- 9次/分钟；P < 0.05），在RA时保持降低（157 +/- 5次/分钟）；（3）计算得出的PV在AA时比SL基线值降低6.9 +/- 10.0%，在CA时降低21.3 +/- 11.1%，在RA时降低16.7 +/- 5.4%，并且（4）[La]从AA降低到CA（5.1 +/- 0.9对1.9 +/- 0.4毫摩尔/升；P < 0.05），在RA时保持降低（2.6 +/- 0.6毫摩尔/升）。在SL停留8天后重新进入RA时，在75%VO2peak时，适应反应对于SaO2保留92 +/- 9%，对于PV保留74 +/- 8%，对于[La]保留58 +/- 3%。总之，尽管在海平面停留8天后重新进入高原时次最大运动至 exhaustion时间没有改善，但对于工作、体育比赛或娱乐日程涉及间歇性前往高海拔地区的个体，与高原适应相关的有益运动反应可能会保留。
