We did a lot of work on pulmonary rehabilitation and people with chronic obstructive pulmonary disease, and we demonstrated, quite well, that you could improve outcomes for patients with COPD with pulmonary rehabilitation. You could stop them going into hospital so often, and you could improve the quality of their life and their breathlessness. The work we did on pulmonary rehabilitation was important. At the time, other groups were doing pulmonary rehabilitation, but they weren't asking the patients to do very much. The patients reported that they felt better, but it was difficult to demonstrate physiological changes, and changes in what happened subsequently to them. We really pushed the patients, but they enjoyed that, because they were in groups. They formed clubs, and afterwards they carried on having their pulmonary rehabilitation classes because they had formed bonds with each other. NIV (non-invasive ventilation)was very important. I started using NIV, ad hoc, because I thought it might be a good idea.