At these altitudes, the body usually produces extra red blood cells, thickening the blood and impeding its flow.

在这些海拔高度， 身体通常会产生额外的红细胞，使血液变稠并阻碍其流动。

When you get an infection, your immune system responds by increasing blood flow to the area and sending extra immune cells and enzymes to fight off the infection.

被感染时，免疫系统会做出回应，增加流向这个区域的血液，并派出更多的免疫细胞和生物酶以抵御感染。