Personnel physical activity levels on navy vessels - evidence for soporific and fatigue effects?

Abstract

Among the factors contributing to performance decrements at sea, sopite syndrome and motion induced fatigue are elusive but of considerable interest. The present work attempts to quantify these effects by evaluating the decrease of personnel physical activity while underway. Activity evaluation was based on actigraphy data, an approach used previously on a high speed catamaran, FSF-1 Sea Fighter, although the seas were calm resulting in little motion influence. The present work extends this approach by analyzing crew activity decrease during significant sea states on two high speed vessels, HSV-2 SWIFT (19 participants, 8-day period), and again on the FSF-1 Sea Fighter (13 participants, 12-day period). During the data collection periods, personnel were conducting their normal duties in sea states ranging from 3 to 6.