The participation trends in the ‘Marathon Swim’ in Lake Zurich are presented in Table 1. Between 2002 and 2012, a total of 300 swimmers, including 111 women (37%) and 189 men (63%), finished the race. Twelve women (10.8%) and 68 men (36.0%) started in the wetsuit category, 99 women (89.2%) and 121 men (64.0%) started without wearing a wetsuit