heart races可不是“心脏比赛”，而是“心跳加速；心怦怦跳”。

【例句】
Your heart races when you're falling in love with someone.
当你爱上某个人时，你的心会怦怦跳。

When a pilot flies a plane through a storm, his heart races, his breath becomes shallow, and his attention is intensely focused on the job at hand.
当飞行员驾驶着飞机要穿过一个风暴，他的心脏会加速跳动、他的呼吸变浅、他的注意力强烈地集中在当前任务。