Mental performance of air crew following layovers on transzonal flights.

Studies of transzonal travel indicate that desynchronization of performance and physiological rhythms occurs following long-haul flights. In an attempt to overcome the problems associated with such desynchronization, air crew are given layover periods en route. The extent to which such layovers are effective in removing performance deficit, however, has not been studied. The present study was designed to remedy this situation by investigating performance levels following layover periods on both eastward and westward long-haul flights. The results suggest that layovers may largely eliminate performance deficits but only if flight times are such that air crew may maintain a reasonably normal sleep-rest cycle.