Shortness of breath, also known as dyspnea is a common finding in many older adults. It's usually linked with a heart or lung problem, but not always.

Many hip fracture patients were very sedentary before their fall or fracture. The gradual decline of muscle function and deconditioning affects all the muscles. This includes the heart and respiratory muscles of the trunk.

The combined effects of sedentary lifestyle, deconditioning, and major surgery can cause new symptoms to develop. Rehab itself is probably more strenuous than your mother's previous activities at home. It's likely she didn't do anything that made her short of breath.

Many older adults stop doing activities that bring on a bout of breathlessness. When they start increasing their activity level in rehab the cardiopulmonary system is stressed and dyspnea occurs.

Make sure you report this to the staff. Ask her doctor about it. New onset of any symptom of this type is a yellow flag that must be checked out.