The human spleen can contract and transiently boost the blood with stored erythrocytes. We measured spleen volume and contraction during apneas in two groups, each containing 12 Caucasian participants (each 3 women): one group planning to summit Mt. Everest (8848 m; “Climbers”) and another trekking to Everest Base Camp (5300 m; “Trekkers”). Tests were done in Kathmandu (1370 m) 1–3 days after arrival, before the Climb/Trek. Age, height, weight, vital capacity, resting heart rate, and arterial oxygen saturation were similar between groups (not significant). After 15 minutes of sitting rest, all participants performed a 1-minute apnea and, after 2 minutes of rest, 1 maximal duration apnea was performed. Six of the climbers did a third apnea and hemoglobin concentration (Hb) was measured. Three axial spleen diameters were measured by ultrasonic imaging before and after the apneas for spleen volume calculation. Mean (standard deviation) baseline spleen volume was larger in Climbers [367 (181) mL] than in Trekkers [228 (70) mL; p = 0.022]. Spleen contraction occurred during apneas in both groups, with about twice the magnitude in Climbers. Three apneas in six of the Climbers resulted in a spleen volume reduction from 348 (145) to 202 (91) mL (p = 0.005) and an Hb elevation from 147.9 (13.1) to 153.3 (11.3) g/L (p = 0.024). Maximal apneic duration was longer in Climbers [88 (23) seconds vs. 67 (18) seconds in Trekkers; p = 0.023]. We concluded that a large spleen characterizes Climbers, suggesting that spleen function may be important for high-altitude climbing performance.

中文翻译：

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高山呼吸暂停期间的脾脏体积和收缩 珠穆朗玛峰登山者和珠穆朗玛峰大本营徒步旅行者。

人的脾脏可以收缩并通过储存的红血球暂时增强血液。我们测量了两组呼吸暂停期间脾脏的体积和收缩情况，每组包含12位白种人参与者（每位3位女性）：一组计划登顶山。珠穆朗玛峰（8848 m；“登山者”），然后徒步前往珠穆朗玛峰大本营（5300 m；“徒步旅行者”）。到达后1-3天，在加德满都（1370 m），爬升/跋涉之前进行了测试。两组之间的年龄，身高，体重，肺活量，静息心率和动脉血氧饱和度相似（不显着）。坐姿休息15分钟后，所有参与者进行1分钟的呼吸暂停，休息2分钟后，进行1次最大持续时间的呼吸暂停。六个登山者进行了第三次呼吸暂停，并测量了血红蛋白浓度（Hb）。在呼吸暂停之前和之后通过超声成像测量三个轴向脾脏直径以计算脾脏体积。登山者的平均脾脏体积（标准偏差）为[367（181）毫升]，而跋涉者的平均脾脏体积为[228（70）毫升]。p  ＝ 0.022]。两组均在呼吸暂停期间发生脾收缩，在登山者中约为脾收缩的两倍。六个登山者中的三个呼吸暂停导致脾脏体积从348（145）降至202（91）mL（p  = 0.005）和Hb从147.9（13.1）降至153.3（11.3）g / L（p  = 0.024） ）。登山者的最大呼吸暂停持续时间更长[88（23）秒，而登山者为67（18）秒；p  ＝ 0.023]。我们得出的结论是，登山者具有大型脾脏的特征，这表明脾脏功能对于高海拔攀爬性能可能很重要。