Fatigue in airline pilots after an additional day's layover period.
BACKGROUND
We investigated the effect of an additional day's layover on reducing fatigue in two different duties: a two-pilot crew flying between Auckland and Brisbane, and a three-pilot crew flying between Auckland and Los Angeles.


METHODS
Pilots completed a reaction time task, the Samn-Perelli fatigue scale, and the Karolinska Sleepiness Scale on both outward and return flights. The flights were conducted with and without a 1-d layover (Brisbane) and with a 1- or 2-d layover (Los Angeles).


RESULTS
On the Brisbane route, the addition of a layover resulted in a significant reduction of fatigue, sleepiness, and reaction time. At top of descent, Samn-Perelli fatigue was reduced from over 5.0 to under 4.5. In contrast, the addition of an extra day layover in Los Angeles had no significant effect on the same measures during the return flight; on both flights Samn-Perelli fatigue was over 5.0 at top of descent.


CONCLUSIONS
The results suggest that the addition of an extra night's layover has different effects depending on the type of operation. Layover periods need to ensure adequate opportunity to recover from any sleep deficit arising from the outbound journey, but the benefit of increased layover time may be limited if time-zone shifts cause a mismatch between local time and the circadian rhythm of sleep.
Medical Unit, Air New Zealand Ltd., Auckland, New Zealand. david.powell@airnz.co.nz
David M C
DM
Powell
Mick B
MB
Spencer
Keith J
KJ
Petrie
D000337:Aerospace Medicine; D016022:Case-Control Studies; D005221:Fatigue / Q000517:prevention & control*; D006801:Humans; D020179:Jet Lag Syndrome / Q000517:prevention & control*; D011930:Reaction Time; D013997:Time Factors; D014940:Work Schedule Tolerance