a common misconception that breathing in a larger volume of air increases the oxygenation of the blood；一个普遍存在的误解是：吸入更多的空气会增加血液中的含氧量

It is physiologically impossible to increase the oxygen saturation of the blood in this way, because the blood is almost always already fully saturated. It would be like pouring more water into a glass that is already filled to the brim；从生理学上来说，通过这种方式增加血液中的氧气饱和度是不可能的；因为血液中的氧气几乎是已经完全饱和了，这就像把更多的水倒进一个已经装满了水的杯子里一样无效；

Oxygen saturation (SpO2) is the percentage of oxygen-carrying red blood cells (hemoglobin molecules) containing oxygen within the blood；血氧饱和度是指与氧气结合的血红蛋白占血红蛋白总量的比例

During periods of rest the standard breathing volume for a healthy person is between 4 and 6 liters of air per minute, which results in almost complete oxygen saturation of 95 to 99 percent；安静状态下，人体每分钟大约吸入4—6升空气，氧气饱和度为95%—99%

Because oxygen is continually diffusing from the blood into the cells, 100 percent saturation is not always feasible. An oxygen saturation of 100 percent would suggest that the bond between red blood cells and oxygen molecules is too strong, reducing the blood cells’ ability to deliver oxygen to muscles, organs, and tissues；因为血液中的氧气不断的被运送到细胞，所以血氧饱和度不会达到100%；如果血氧饱和度为100%，则表明血红蛋白与氧分子的结合太强烈，减弱了红细胞向肌肉、器官及组织输送氧气的能力

We need the blood to release oxygen, not hold on to it. 我们需要血液释放氧气，而不是保存氧气

The human body actually carries a surplus of oxygen in the blood—75 percent is exhaled during rest and as much as 25 percent is exhaled during physical exercise. Increasing oxygen saturation to 100 percent has no added benefits.人体存有过量的氧气——安静状态下，75%通过呼吸排出体外，运动时只有25%排出体外；把血氧饱和度提高到100%并没有额外的好处

The idea of taking bigger breaths to take in more oxygen is akin to telling an individual who is already eating enough food to provide their daily caloric needs that they need to eat more；通过呼吸大量的空气以摄入更多的氧气，如同让已经吃了足够的食物来提供每日所需热量的人，告诉他们需要再吃更多

—— Patrick McKeown，The Oxygen Advantage

•在实践中发现，一组运动练习中呼吸越用力，练习结束后会更容易气喘吁吁；而如果通过深呼吸去调整，反而可能会喘的更加厉害；严重者则会出现头晕、眼花等现象；