Health insurance list of what is 'reimbursable' does not include swimming (lanes) without supervision for medical reasons (physiotherapist) to resolve and keep at bay back-problems.
Patients with mobility issues requiring swimming to be reimbursable on prescription from the physiotherapist.
Only swimming (lanes) under the supervision of a physiotherapist is reimbursable whereas there are patients that require frequent swimming (lanes) yet can do so without supervision of a physiotherapist is a variant that is not reimbursable yet equally costly to the patient.
Health Insurance includes swimming (lanes) for medical reasons without supervision to be reimbursable.