1. Department of Anaesthetics, Northumbria Specialist Emergency Care Hospital, Cramlington, Northumberland, NE23 6NZ, UK.
2. School of Clinical and Applied Sciences, Leeds Beckett University, Leeds, LS1 3HE, UK.
3. Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, S10 2BP, UK.
4. Institute of Respiratory Medicine and Exercise Physiology, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Centre, Torrance, CA 90502, USA.