Feb 182010

imageEvery seafarer should be familiar with sleep debt but new research suggests that ‘sleep credit’ is also possible. In effect you can bank your sleep before heading for long, fatiguing hours.

Fatigue is a key ingredient many incidents, groundings and collisions in particular. Indeed, it is almost certain that officers on watch fall asleep far more often that realised and possibly even more often than officers themselves realise: If you fall asleep and dream that you’re on watch you may never realise that you actually did fall asleep.

Even if the bridge watch alarm goes off a sleeping officer can cancel it while still snoozing. There are reports of officers of the watch sleeping their eyes open and unaware of a hand passed in front of their faces.

More common is a level of fatigue that takes the edge off of situational awareness and perception with a loss of good decision-making skills.

image Now, MAC’s favourite boffin rag, New Scientist, reports on research at the Walter Reed Army Institute of Research that might be good or bad news.

Half of a group of volunteers was allowed extra sleep for a week, the other half kept to its normal sleep patterns. For the next week the volunteers were allowed just three or four hours of sleep each night.

Reports New Scientist: “After this week of either extended or habitual sleep per night, all the volunteers came to the lab and they were given three hours of sleep, per night, for a week,” explained Tracy Rupp from the Walter Reed Army Institute of Research.

“They were then given tasks of varying complication, and tests showed that those who had banked the sleep were “more resilient during the sleep restriction”.

“They showed less performance deterioration with regards to reaction time and alertness than the group that had been given the habitual prior sleep,” said Ms Rupp.

“The tests even showed that a week after the experiment the pre-stored sleepers were recovering better from their sleep deprivation than the habitual sleepers.

“What we’re basically saying is if you fill up your reserves and pay back your sleep debt ahead of time, you’re better equipped to deal with the sleep loss challenge.”

Ms Rupp also says: “One way you might be able to capitalize and get some extra sleep is napping… Although this study didn’t use napping, it has been shown to be very effective, at least improving performance in the short term.”

The bad news is that it won’t resolve the issue of ‘safe manning’ levels aimed at putting the minimum number of seafarers on a ship rather than the safe minimum number of seafarer on the ship and which lead to officers being fatigued. Resolving that issue will take more political will than currently seems to be available.


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