Mark Harper is a consultant anaesthetist at Brighton and Sussex University Hospitals who, accidentally and via quite unrelated routes, has developed an interest in the negative effects of getting cold during surgical operations and the positive effects of cold water swimming.

His professional life and his PhD are based around keeping patients warm. However, his research increasingly involves immersing people (and himself) in cold water in collaboration with the Extreme Environments Laboratory at Portsmouth University.

Other roles include being an expert advisor to NICE on a number of perioperative hypothermia guidelines, lead for the Kent, Surrey and Sussex CRN, Honorary Clinical Senior Lecturer at Brighton and Sussex Medical School and Honorary School Fellow at the University of Brighton.