Dr Sonners explains claustrophobia in a hyperbaric chamber Many folks are worried about being claustrophobic inside the chamber. Some go to sit down chambers. But most find that they get used to the chamber quickly. Especially if they buy a 33 or 34 inch chamber or larger. Here’s a great trick. Lean against the door frame and look over to the other side of the door. That will be the amount of space you are looking at once your chamber is inflated.