In usual breathing, the ribs move up and down every time you breathe. In ankylosing spondylitis, the rib joints that join to the spine can stiffen or even fuse since of inflammation. As a result, the ribs can lose their capability to rise and fall. This chest wall lessening, which some describe as an emotion of being strapped in, leaves public feeling short of breath, still after mild activities. If the ribs fuse, you will still be capable to breathe — the main muscle used in breathing, the diaphragm, isn't affecting — but not extremely.
“Costochondritis can reason chest pain with ankylosing spondylitis”
Just as exercise can keep your spine supple, deep-breathing exercises can keep your chest wall elastic and conserve your capability to take a deep, purification breath — significant because, without these protective steps, ankylosing spondylitis preserve make deep breathing hard or even not possible.