Flights are usually overnight and only a short sleep is normally possible often before the night-time sleep gate is reached. Our bodies find it almost impossible to shorten the 24 hour cycle. We would require two days of 21 hours or three of 22 hours to compensate. Probably the best alternative is to elect for one day of 42 hours. The disruption of our cycle may take up to ten days to repair and to bring our biological clock into synchrony with local timing.
Circadian performance rhythms.
Vigilance, theory, operational performance and physiological correlates. The disrupting effect of shift work upon people's lives is of enormous importance. Sleep, sleepiness and performance. Constant changing of shift can be detrimental to alertness and well being. Certain shift patterns are worse than others.