Ocular circulatory responses to exhaustive exercise in humans
Ocular circulatory responses to exhaustive exercise in humans
复制标题
DOI：
10.1007/s00421-012-2313-0
复制
发表时间：
2012-09-01
影响因子：
3
通讯作者：
Hayashi, Naoyuki
中科院分区：
文献类型：
--
作者：
Ikemura, Tsukasa;Hayashi, Naoyuki
目前还不清楚是否详尽的动态运动增加眼血流量，虽然我们已经报道，亚极量运动增加眼血流量。我们假设，眼血流量减少，在疲惫，因为疲惫会导致过度换气，从而导致PaCO 2的减少。为了验证这一假设，在12名健康男性受试者中进行了眼血流量、血压和呼吸测量，这些受试者在自行车测力计运动中以最大心率的75%进行运动，直到精疲力竭。在运动过程中，每隔3分钟用激光散斑血流图测量视网膜和脉络膜血管系统（RCV）、视网膜上级颞侧小动脉（STRA）和视网膜上级鼻侧小动脉（SNRA）的血流量。通过将血流除以平均动脉压（MAP）计算眼血管系统中的传导指数（CI）。根据潮气量和潮气末CO2分压估计平均动脉CO2分压（PaCO 2）。在整个运动过程中，MAP从静息基线显著增加，而PaCO 2在疲惫时和恢复期显著降低。运动开始后6分钟，RCV的血流速度较静息基线值显著增加32 +/- A 6%（平均值+/- A SD）。力竭时，RCV的血流速度与静息基线值无显著差异，STRA血流显著降低13 +/-A4%。与基线相比，RCV、STRA和SNRA的CI在耗竭时显著降低。这些发现表明，次极量运动增加了眼血流量，而与疲惫相关的低碳酸血症则抑制了眼血流量。
It is unclear whether exhaustive dynamic exercise increases ocular blood flow, although we have reported that submaximal exercise increases ocular blood flow. We hypothesized that ocular blood flow decreases at exhaustion, since exhaustion causes hyperventilation, which induces a reduction in PaCO2. To test this hypothesis, ocular blood flow, blood pressure, and respiratory measurements were made in 12 healthy male subjects during cycle ergometer exercise at 75% of maximal heart rate, until exhaustion. Blood flows in the retinal and choroidal vasculature (RCV), the superior temporal retinal arteriole (STRA), and the superior nasal retinal arteriole (SNRA) were measured with the aid of laser-speckle flowgraphy every 3 min during the exercise. The conductance index (CI) in the ocular vasculature was calculated by dividing the blood flow by the mean arterial pressure (MAP). The mean arterial partial pressure of CO2 (PaCO2) was estimated from tidal volume and end-tidal CO2 partial pressure. MAP significantly increased from the resting baseline throughout the exercise, while PaCO2 was significantly decreased at exhaustion and during the recovery period. By 6 min after the onset of exercise, blood flow velocity in the RCV significantly increased by 32 +/- A 6% (mean +/- A SD) from the resting baseline value. At exhaustion, blood flow velocity in the RCV did not differ significantly from the resting baseline value, and the STRA blood flow was significantly decreased by 13 +/- A 4%. The CIs in the RCV, STRA, and SNRA were significantly decreased compared to baseline at exhaustion. These findings suggest that ocular blood flow is increased by submaximal exercise, whereas it is suppressed by the hypocapnia associated with exhaustion.