title: Cognitive function during lower body water immersion and post-immersion afterdrop.
abstract: BACKGROUND
  The physiological effects of immersion hypothermia and afterdrop are well-characterized, but the psychological effects are less clear. The purpose of this study was to quantify changes in cognitive function during and after lower body water immersion.
  
  
  METHODS
  On separate mornings, nine young healthy men participated in both neutral (35 +/- 1 degree C) and cold (13 +/- 1 degree C) water immersion. Subjects rested in neutral air for 30 min followed by 60 min water immersion to the iliac crest and 15 min of recovery in neutral air. Rectal temperature and mean skin temperature were continuously monitored. Metabolic rate, the Stroop Color Word Test (SCWT), and the Profile of Mood State (POMS) were quantified at predetermined intervals.
  
  
  RESULTS
  During immersion in cold water, rectal temperature was reduced, but SCWT and POMS scores were unchanged relative to baseline. Despite the reduced rectal temperature, little to no shivering was observed during immersion and metabolic rate did not change. During recovery from cold immersion, rectal temperature was further reduced by approximately 0.5 degree C, shivering was noted, and metabolic rate increased. Coincident with this acute afterdrop, SCWT Color-Word performance (delta = -4 +/- 8 vs. 7 +/- 6 correct responses) and Interference score (delta = -2 +/- 7 vs. 4 +/- 8) was impaired relative to recovery from neutral immersion (i.e., when core temperature and metabolic rate did not change).
  
  
  CONCLUSIONS
  These results suggest that recovery from lower body cold water immersion elicits the afterdrop phenomenon and shivering, which together impair selective attention as measured by the SCWT.
authors.affiliation: Exercise and Environmental Physiology Laboratory, Kent State University, Kent, OH 44242, USA.
authors.forename: Yongsuk
authors.initials: Y
authors.lastname: Seo
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Kim
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Ryan
authors.forename: John
authors.initials: J
authors.lastname: Gunstad
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Glickman
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Muller
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D001481:Basal Metabolism / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D003080:Cold Temperature; D018592:Cross-Over Studies; D006801:Humans; D007035:Hypothermia / Q000503:physiopathology; D007101:Immersion; D008297:Male; D009483:Neuropsychological Tests; D020127:Recovery of Function / Q000502:physiology; D012768:Shivering / Q000502:physiology; D014867:Water; D055815:Young Adult
chemical_list: D014867:Water