Project 454619

Individuals who are born with a single functional ventricle undergo the Fontan surgical procedure. This procedure redirects blood flow from the lower body directly to the lungs. However, although increasing life-expectancy of "Fontan patients", this procedure is not free of chronic side effects. One disabling condition common to most Fontan patients is weakness of respiratory muscles. This condition not only increases the sensation of breathlessness during any physical activity but initiates a vicious cycle that reduces oxygen to the lower limb muscles (through increased sympathetic activation) and limits tolerance to exercise. In this context, an exercise intervention that specifically targets the respiratory muscles may be an effective strategy to increase their respiratory capacity and to improve exercise tolerance and overall quality of life in these patients. Thus, this project aims to evaluate the efficacy of individualized respiratory muscle training on a wide array of perceptual, physiological, and exercise performance-related outcomes in adults who have undergone the Fontan procedure. It is hypothesized that Fontan patients who participate in 8-weeks of individualized respiratory muscle training will demonstrate a significant improvement in breathlessness ratings, cardiorespiratory function, exercise capacity, and overall quality of life compared to Fontan patients who will receive a Sham intervention. If these hypotheses are proven correct, the findings of this project will set the standards for the adoption of respiratory muscle training within cardiorespiratory rehabilitation programs in Fontan patients.