So, everyone trains themselves, breath holding and cardio and getting comfortable in scary situations.

所以，每个人都训练自己，屏气和有氧运动，在可怕的情况下从容自如。

Bradycardia is the slowing of the heart rate in response to cold water and breath holding.

心动过缓是对冷水和屏气反应的心率减慢。