Influence of a Swimming Program on the Lung Function Status of Children With Cystic Fibrosis

Sir.—In the January 1986 issue of AJDC, one finds an interesting article by Edlund and coworkers¹ describing the effects of a 12-week swimming program on the clinical status, lung function, and exercise tolerance of children with cystic fibrosis (CF). By comparing ten exercising children with CF with a control group that did not swim, the authors found an improvement of clinical status and exercise tolerance after the program; the measured lung function variables, however, did not change significantly.

Before it becomes a widely accepted take-home message (swimming does not improve lung function in children with CF), this result deserves some critical comment: (1) There are some uncertainties related to the method for lung function assessment in the above article.¹ A spirometer alone can never measure residual volume; the assessment of this variable necessitates the use of helium dilution techniques or body plethysmography. (2) Lung function is presented