NORFOLK, Va. — For sailors aboard deployed Navy ships, little sleep has long come with the territory.
It's partly a function of the job: A ship at sea is an around-the-clock operation. On top of drills, meetings and daily work, most sailors must also stand watch - on the bridge, in engine rooms, in front of screens in darkened operations centers - on schedules that give little regard to the body's circadian rhythm. One day a sailor might be on watch all morning, and the next all night.
It's partly culture, too: Among sailors, the ability to push on for months at a time with little sleep and no days off is seen as a badge of honor.
Aboard more and more ships, though, that is changing. Rather than seeing it as a point of pride, Navy officials are working to recast fatigue as an unnecessary risk that causes costly mistakes, and some commanding officers are taking significant steps to help their sailors get more and better sleep.
Most notably, an increasing number are scheduling watch shifts that align with the body's 24-hour clock and allow sailors to sleep at the same time each day - a big change from the way the service has long operated.
"It's a paradigm shift," said John Cordle, a recently retired Navy captain who has been championing better sleep for sailors for years. "And it's catching on."
The destroyer Truxtun, which left Norfolk on Saturday with the aircraft carrier George H.W. Bush, tried a circadian-based schedule while training this summer and decided to keep it for the deployment.
Said the ship's senior watch officer, Lt. Kori Levy-Minzie, "It's noticeable that people are more alert and less tired."
The key difference is that traditional watch schedules ignore the body's circadian rhythm. Among the most common rotations, for example, is what the Navy calls the "five and dime." Watch standers are on duty for five hours, then have 10 hours to sleep, exercise and take care of other work. Their watch shifts always begin at different times. One day, their chance to sleep might start at 5 a.m., and the next at 8 p.m.
That keeps the body constantly confused, which makes it harder to fall asleep, said Nita Shattuck, a professor at the Naval Postgraduate School in Monterey, Calif., who has studied crew rest aboard numerous ships.
"Even though they can be very fatigued, their bodies just aren't ready to sleep," Shattuck said.
With circadian-based schedules, she said, "the quality of the sleep is superior. They're getting more benefits from it."
Shattuck spent a month aboard the Norfolk-based destroyer Jason Dunham while it was deployed in 2012. A portion of the crew used a traditional schedule while others used an alternative - three-hour watches before nine hours off - that gave them a long block for rest at the same time each day. Sailors used wrist monitors and smart phones to track their sleep and reaction times.
An analysis showed that those on the alternative rotation were more alert. Shattuck considers the three-on, nine-off schedule to be the best for crew rest.
It's the same one the Truxtun is using. Petty Officer 1st Class Sandra Flowers said she likes it. As a sonar technician, she spends her watch shifts tracking nearby vessels, whales and dolphins. "Staring at a display for hours - you have to stay attentive," she said. "This makes it easier."
Said Petty Officer 3rd Class Eric Lettow, a boatswain's mate: "Now I have time to get things done other than try to sleep."
Critics of the change have knocked it as another example of the military going soft. But proponents disagree. "This is just the opposite," Shattuck said. "It's about performance. It's about building crew endurance and making them stronger."
Research has shown long-lasting consequences among civilian workers with inconsistent and overnight shifts, she said, and many private employers have come to understand the value of a well-rested workforce.
So has the Coast Guard, and even Navy aviators are required to sleep a minimum number of hours before flying. Among sailors who man and oversee ships, rest has been a low priority.
In May, though, two top admirals in charge of the Navy's surface ships issued a message to the fleet endorsing watch schedules designed to give sailors more sleep. "The aviation community has long embraced the concept of crew rest as a foundation for safe operations," said Vice Adm. Tom Copeman and Rear Adm. David Thomas. "It has a place in the surface force as well."
Safety and effectiveness are the biggest reasons sailors need better sleep, they said, noting that fatigue has played a role in ship groundings and collisions. In a January 2013 article in the U.S. Naval Institute magazine Proceedings, Cordle wrote that too little rest was cited as a factor in nearly 80 percent of Navy mishaps.
Cordle saw other benefits, too - namely improved morale - when he tried the three-on, nine-off schedule as commanding officer of the Norfolk-based cruiser San Jacinto in 2010. Sailors were less stressed, and they found more time to exercise, he said.
He has trumpeted circadian schedules since. "Working and sleeping the same hours each day paid huge dividends," he wrote in Proceedings. As for sleeplessness as a badge of honor, he wrote, "it does not have to be that way."
Cmdr. Seth Burton, skipper of the Norfolk-based submarine Scranton, said he's become a believer, too.
On a seven-month deployment that ended last month, Scranton watch standers were on for eight hours and then off for eight - a big shift from the six-hour rotations that submariners are used to. "It was the best-rested crew I've ever seen," Burton said.
He had to get special permission to use the schedule because submariners were limited by policy to six-hour watches. That recently changed, and Burton said other subs have made the transition.
But he and others warn that starting such schedules isn't like flipping a switch, and it doesn't work for every vessel.
On the San Jacinto and the Truxtun, meal times had to be extended, and meetings and announcements were restricted to day hours. The ships even did away with the long-standing tradition of morning reveille and evening taps.
"It's a whole program," Cordle said. "You have to tweak the entire ship's routine."
Kinks must be ironed out, and extra watch standers must be trained to cover additional shifts that turn over more often.
And some vessels simply don't have enough qualified personnel to allow all watch standers a circadian routine with long blocks of time for rest.
The Navy is working to boost staffing on ships after years of downsizing, which officials acknowledge added to sailors' fatigue.
As much as supporters want to see circadian schedules spread, few think the practice should be mandated from the top; rather, most say it should stay a choice made ship by ship.
"It's working well for us," said the Truxtun's commanding officer, Cmdr. Andrew Biehn. "But it's not one-size-fits-all."