Forbes S C, Kowalchuk J M, Thompson R T, Marsh G D
School of Kinesiology, The University of Western Ontario, London, Ontario, Canada.
J Appl Physiol (1985). 2007 Apr;102(4):1565-73. doi: 10.1152/japplphysiol.00895.2006. Epub 2007 Jan 11.
The effects of controlled voluntary hyperventilation (Hyp) on phosphocreatine (PCr) kinetics and muscle deoxygenation were examined during moderate-intensity plantar flexion exercise. Male subjects (n = 7) performed trials consisting of 20-min rest, 6-min exercise, and 10-min recovery in control [Con; end-tidal Pco(2) (Pet(CO(2))) approximately 33 mmHg] and Hyp (Pet(CO(2)) approximately 17 mmHg) conditions. Phosphorus-31 magnetic resonance and near-infrared spectroscopy were used simultaneously to monitor intramuscular acid-base status, high-energy phosphates, and muscle oxygenation. Resting intracellular hydrogen ion concentration (H(+)) was lower (P < 0.05) in Hyp [90 nM (SD 3)] than Con [96 nM (SD 4)]; however, at end exercise, H(+) was greater (P < 0.05) in Hyp [128 nM (SD 19)] than Con [120 nM (SD 17)]. At rest, [PCr] was not different between Con [36 mM (SD 2)] and Hyp [36 mM (SD 1)]. The time constant (tau) of PCr breakdown during transition from rest to exercise was greater (P < 0.05) in Hyp [39 s (SD 22)] than Con [32 s (SD 22)], and the PCr amplitude was greater (P < 0.05) in Hyp [26% (SD 4)] than Con [22% (SD 6)]. The deoxyhemoglobin and/or deoxymyoglobin (HHb) tau was similar between Hyp [13 s (SD 8)] and Con [10 s (SD 3)]; however, the amplitude was increased (P < 0.05) in Hyp [40 arbitrary units (au) (SD 23)] compared with Con [26 au (SD 17)]. In conclusion, our results indicate that Hyp-induced hypocapnia enhanced substrate-level phosphorylation during moderate-intensity exercise. In addition, the increased amplitude of the HHb response suggests a reduced local muscle perfusion in Hyp compared with Con.
在中等强度的跖屈运动期间，研究了控制性自主过度通气（Hyp）对磷酸肌酸（PCr）动力学和肌肉去氧作用的影响。男性受试者（n = 7）在对照[Con；呼气末二氧化碳分压（Pet(CO(2))）约为33 mmHg]和Hyp（Pet(CO(2))约为17 mmHg）条件下进行了包括20分钟休息、6分钟运动和10分钟恢复的试验。同时使用磷-31磁共振和近红外光谱来监测肌肉内酸碱状态、高能磷酸盐和肌肉氧合。休息时，Hyp组[90 nM（标准差3）]的细胞内氢离子浓度（H(+)）低于Con组[96 nM（标准差4）]（P < 0.05）；然而，在运动结束时，Hyp组[128 nM（标准差19）]的H(+)高于Con组[120 nM（标准差17）]（P < 0.05）。休息时，Con组[36 mM（标准差2）]和Hyp组[36 mM（标准差1）]的[PCr]无差异。从休息到运动过渡期间PCr分解的时间常数（tau）在Hyp组[39秒（标准差22）]大于Con组[32秒（标准差22）]（P < 0.05），并且Hyp组[26%（标准差4）]的PCr幅度大于Con组[22%（标准差6）]（P < 0.05）。Hyp组[13秒（标准差8）]和Con组[10秒（标准差3）]之间的脱氧血红蛋白和/或脱氧肌红蛋白（HHb）tau相似；然而，与Con组[26任意单位（au）（标准差17）]相比，Hyp组[40任意单位（au）（标准差23）]的幅度增加（P < 0.05）。总之，我们的结果表明，Hyp诱导的低碳酸血症在中等强度运动期间增强了底物水平磷酸化。此外，HHb反应幅度的增加表明与Con组相比，Hyp组局部肌肉灌注减少。
