Shipboard rest, sleep, and seasickness: Evidence of interaction

Sea‐keeping trials of a United States Coast Guard cutter included a human factors engineering evaluation having particular regard to problems of seasickness in certain work stations. Some motion sickness incidence and related data, and the derivation of human factors engineering principles therefrom, were reported in 1985 [A. C. Bittner, Jr. and J. C. Guignard, Nav. Eng. J. 97 (4), 207–213; 97 (5), 107–111]. Further analysis [A. C. Bittner, Jr. and J. C. Guignard, in Trends in Ergonomics/Human Factors V, edited by F. Aghazadeh (Elsevier, New York, 1988), pp. 529–539] showed that, contrary to traditional assumptions, seasickness is characterized by at least two functionally independent factors, identified as F1 (symptomatic general motion illness) and F2 (retching‐vomiting). It was shown that the validity of future sea trials requires: (a) multiple‐score scaling of motion sickness (e.g., using F1 and F2); (b) control of subject crew activity and movements about the ship during periods of observation; and (c) avoidance of steaming patterns that induce extraneous carryover effects. The present paper draws attention to an incidental finding concerning the influence of brief sleep and rest (lying down in the bunk) upon motion sickness susceptibility and recovery in the shipboard environment. Analyses of questionnaire data including amount and subjective quality of sleep showed that these were affected by the passage of time in an adverse (nauseogenic) motion environment, as has been observed generally in naval operations. An apparent ameliorative effect of unscheduled rest periods and naps upon susceptibility to adverse motion effects was incidentally detected and is commented upon in this report. [Observations made while the authors were at the Naval Biodynamics Laboratory, New Orleans.]