title: Seating type and cognitive performance after 3 hours travel by high-speed boat in sea states 2-3.
abstract: BACKGROUND
  Transit in high-speed marine craft subjects occupants to a rough ride as the boat impacts the waves. This induces high levels of physical stress, which may inhibit cognitive performance during military operations and life-saving activities. Land-based research suggests that suspension seats reduce vibration and, therefore, stress. We hypothesized that subjects using suspension seats would demonstrate better cognitive performance, lower perceptions of exertion, fatigue, and sleepiness, and lower salivary concentrations of cortisol than those using fixed seats.
  
  
  METHODS
  Subjects, naval personnel, were divided into fixed (N = 6) and suspension seat (N = 6) groups. Subjects undertook forward and backward number recall and random number generation tests pre- and post-transit (3 h in sea states 2-3). Salivary cortisol concentrations were sampled pre- (1100 h) and post-transit (1700 h) and at the same times on a control day. Post-transit perceptions of exertion, fatigue, and sleepiness were measured subjectively.
  
  
  RESULTS
  The suspension seat group demonstrated better performance post-transit than the fixed seat group for forward number recall and showed a significant pre- to post-transit improvement in backward number recall. The suspension seat group reported less fatigue and sleepiness. The suspension seat group had significantly higher salivary cortisol concentrations than the fixed seat group post-transit. Regression analyses found a quadratic correlation between delta cortisol concentrations and delta random number generation scores (R2 = 0.68).
  
  
  CONCLUSIONS
  Results show that the use of suspension seats during transit in high-speed marine craft may be advantageous with regard to cognitive performance.
authors.affiliation: Faculty of Sport, Education and Social Sciences, University of Chichester, Chichester, UK. t.mcmorris@chi.ac.uk
authors.forename: Terry
authors.initials: T
authors.lastname: McMorris
authors.forename: Stephen
authors.initials: S
authors.lastname: Myers
authors.forename: Trevor
authors.initials: T
authors.lastname: Dobbins
authors.forename: Ben
authors.initials: B
authors.lastname: Hall
authors.forename: Rosemary
authors.initials: R
authors.lastname: Dyson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003071:Cognition / Q000502:physiology*; D006970:Disorders of Excessive Somnolence / Q000209:etiology / Q000517:prevention & control*; D004867:Equipment Design; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D009326:Naval Medicine; D009784:Occupational Diseases / Q000517:prevention & control*; D012044:Regression Analysis; D012307:Risk Factors; D012463:Saliva / Q000737:chemistry; D012767:Ships; D011795:Surveys and Questionnaires; D013997:Time Factors; D014732:Vibration
chemical_list: D006854:Hydrocortisone