This is the 12117th most frequent Korean word.
누웠는데
"누웠는데" means "lay down, but/and" in English.
Here, '누웠는데' describes an action that occurred ('I lay down') leading to the subsequent event ('I fell asleep immediately').
어제 너무 피곤해서 침대에 누웠는데 바로 잠들었어요.
Yesterday, I was so tired that I lay in bed and immediately fell asleep.
'누웠는데' is used to indicate the action of lying down on the floor after exercising, followed by the observation of feeling refreshed.
운동을 열심히 하고 나서 바닥에 누웠는데 정말 시원했어요.
After exercising hard, I lay on the floor and it felt really refreshing.
In this sentence, '누웠는데' reflects the action of lying down after coming indoors, leading to the feeling of comfort.