aSchool of Cardiovascular and Metabolic Health, BHF Glasgow Cardiovascular Research Center, College of Medical, Veterinary and Life Sciences

bSchool of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland

cCentre for Human and Applied Physiological Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK

Correspondence to Oliver C. Witard, Centre for Human and Applied Physiological Sciences, Faculty of Life Sciences & Medicine, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK. Tel: +44 207 848 6325; e-mail: [email protected]