But why should they sleep deeply at all? Why should a state of such deep immobilization ever have evolved?

但他们为什么睡得很沉呢？为什么会出现如此深度固定的状态？

According to the passage, the immobilization hypothesis fails to account for which of the following facts?

根据文章，不移动假说没能下哪些事实？

And on top of all that, every two days of immobilization, your resting heart rate increase by one beat per minute, eventually plateauing.

其最严重的是，只固定不动，每两天，你的心脏静息率就会上升每分钟多跳一拍，最后则居高不下。

Prevention of a deep vein thrombosis is also important - compression stockings and frequent calf exercises during long periods of immobilization can help move blood through the veins to prevent stasis.

DVT的预防也很重，弹力袜及长期制动患者进行规律的小腿活动来防止血流瘀滞也是有必的。