External Stimuli Invade our Dreams

This is called Dream Incorporation and it is the experience that most of us have had
where a sound from reality is heard in our dream and incorporated in some way. A similar (though less external) example
would be when you are physically thirsty and your mind incorporates that feeling in to your dream. My own experience of
this includes repeatedly drinking a large glass of water in the dream which satisfies me, only to find the thirst returning
shortly after – this thirst… drink… thirst… loop often recurs until I wake up and have a real drink. - Source: The List Universe