How cold is too cold? Establishing the minimum water temperature limits for marathon swim racing Jane Saycell, Mitch Lomax, Heather Massey, Mike Tipton Department of Sport and Exercise Science, University of Portsmouth, UK Correspondence to: Mike Tipton Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Rd Portsmouth, UK +44 (0)23 9284 5163 michael.tipton@port.ac.uk Keywords: Open water swimming, cold water, wetsuits, non-wetsuit swimming Word count: 3591 Accepted for publication in the British Journal of Sports Medicine on 28/1/19