熬个夜为什么是动词

熬夜的英语短语叫做stay up，它是和动词有关的，比如他经常熬夜，he often stays up他熬夜的非常晚，he stays up late他熬夜，所以呢他现在很困了，he stayed up last night and so he looks very sleepy，所以它是一个动词，在句中常常作谓语。那么经常熬夜呢，对身体是不利的，所以我们不应该经常熬夜，应该怎么说呢

We shouldn't stay up late often because it's bad for our health.