The answer to you question is very simple, Trachea, because a trachea is a large membranous tube reinforced by rings of cartilage, extending from the larynx to the bronchial tubes and conveying air to and from the lungs; the windpipe.
Therefore you answer is,
Trachea.
I hope that this has satisfied you, and if not then feel free to ask questions.
That can be taken many different ways maybe: they push themselves to hard and don’t know when to take a break or they cant settle down, sleep or, don’t know when to stop.