At the end of Week 3 patients will crossover so that those in the GLP-1 treatment arm cross to the placebo arm and vice versa. By incorporating a run-in phase followed by a step-wise increase in Liraglutide therapy over a 3-week period the investigators aim to minimise the occurrence of adverse reactions and also hope to observe a dose-response effect on exercise haemodynamics. The crossover design will allow study participants to effectively act as their own controls.