Is it anoxic to stay in a hotel without windows for one night?

No, a hotel without windows is not a vacuum chamber. Air flows from high pressure to low pressure. At the same time, the amount of air exhaled by the user is less than the amount of air inhaled, so it will not suffocate and lack oxygen, and the user can open the door to breathe. A windowless hotel refers to a room without windows. A room without windows cannot be naturally ventilated and has no natural lighting, and it is completely illuminated by lights.