Participant
An experienced open-water ultra-swimmer (56 years old, 110.2 kg body mass, 1.76 m
body height, BMI of 35.6 kg/m2) participated in the study. The swimmer has a broad
experience in open-water ultra-swimming. For example, in 2011, he was the first swimmer
ever to cross the Fehmarn-Belt from Fehmarn (Germany) to Rødby (Denmark)
and back to Fehmarn (i.e. double crossing) (http://www.bruno-dobelmann.de). In 2012,
he was swimming in water colder than 10°C for 6 h (Rüst et al. 2012). The subject was
healthy, had no medication and no history of non-freezing cold injury such as loss of
sensation, skin damage/infection, or nerve damage.