title: The "Ice-Mile": Case Study of 2 Swimmers' Selected Physiological Responses and Performance.
abstract: OBJECTIVE
  "Ice-mile" swimming presents significant physiological challenges and potential safety issues, but few data are available. This study examined deep body temperature (BT), respiratory rate (RR), and swim performance in 2 swimmers completing an ice-mile swim of 1 mile (1600 m) in water less than 5°C.
  
  
  METHODS
  Two male cold-water-habituated swimmers completed a 1-mile lake swim in 3.9°C water. For comparative purposes, they completed an indoor 1-mile swim in 28.1°C water. The Equivital physiological monitoring system was used to record BT and RR before, during, and after each swim. Total time to complete the swims and 400-m splits were recorded.
  
  
  RESULTS
  One swimmer became hypothermic after 27 min while swimming, reaching BT of 33.7°C at swim's end. On exiting the water the swimmers experienced large BT after-drops of -3.6°C and -2.4°C, reaching low points of 33.2°C and 31.3°C 38 and 23 min postswim, respectively. Respiratory rate and swim pace decreased over the course of the ice-mile swim for both swimmers. Swim pace for 1 swimmer declined sharply in the final 400-m lap of the ice mile when he was hypothermic. Both swimmers remained hypothermic 60 min postswim (34.2°C and 33.4°C).
  
  
  CONCLUSIONS
  Ice-mile swimmers may become hypothermic while swimming, and the postswim BT after drop may expose them to dangerous levels of hypothermia. Pace and RR should be monitored as proxies for a swimmer's physiological state. Postswim recovery should also be monitored for hypothermia for at least 1 h.
authors.forename: John
authors.initials: J
authors.lastname: Kenny
authors.forename: SarahJane
authors.initials: S
authors.lastname: Cullen
authors.forename: Giles D
authors.initials: GD
authors.lastname: Warrington
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D003080:Cold Temperature / Q000009:adverse effects; D006801:Humans; D007035:Hypothermia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D056152:Respiratory Rate / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013997:Time Factors
keywords: after-drop; deep body temperature; hypothermia; respiratory rate; swim performance