1. School of Health Science, City, University of London, Northampton Square; London EC1V 0HB UK
2. Lane Fox Clinical Respiratory Physiology Research Unit, Guy's and St. Thomas' NHS Foundation Trust, Westminster Bridge Road, Lambeth; London SE1 7EH UK
3. Centre for Human and Aerospace Physiological Sciences, King's College London; London SE1 9RT UK
4. Guy's & St Thomas' NHS Foundation Trust and King's College London, National Institute of Health Research Biomedical Research Centre, 16th Floor, Tower Wing, Guy's Hospital, Great Maze Pond; London SE1 9RT UK