This study investigates the effect of breathing profile on aerosol delivery during Nasal High Flow therapy (NHF). NHF is increasingly used across a variety of patient populations. It has the potential for use for the delivery of bronchodilators and hypertonic saline to the airways. Previously the effect of gas flow rate on aerosol delivery has only been assessed using models of a healthy adult. Here we investigate the effect on aerosol delivery efficiency when simulated for both healthy and Cystic Fibrosis (CF). In this study, Albuterol sulphate was aerosolised as a surrogate for hypertonic saline solution. Respiratory exacerbations are a persistent recurring effect in CF. In CF patients’ lungs, epithelial cells produce a thick mucus that clogs the airways and cannot be moved easily. This thick secretion gets stuck in the lungs causing breathing difficulties and also leads to infections. Inhalation of hypertonic saline solution draws water into the mucus, making it easier to clear. We found here, that there is a 9.5-fold difference in efficiency between the minimum and maximum airflow under investigation for CF sufferers, with the lower airflow facilitating greater aerosol delivery. This could have substantial implications on patient care, as delivery of hypertonic saline at low gas flow rates could mean a highly efficient yet comfortable means of administration.