Seating type and cognitive performance after 3 hours travel by high-speed boat in sea states 2-3.
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.
McMorris
Terry
T
Faculty of Sport, Education and Social Sciences, University of Chichester, Chichester, UK. t.mcmorris@chi.ac.uk
Myers
Stephen
S
Dobbins
Trevor
T
Hall
Ben
B
Dyson
Rosemary
R
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
D006854:Hydrocortisone