In War, Fatigue Can Be a Deadly Adversary
Over Time, Mild Sleep Deprivation Can Sap Judgment, Morale and Performance, Experts Say
I thought this issue of using Provigil in war would come up, especially as an alternative to amphetamines (used now by combat pilots.) - Doc
By Shankar Vedantam
Washington Post Staff Writer
Thursday, April 3, 2003; Page A29
Two weeks ago, an Army truck in a convoy racing toward Baghdad dropped out of its group in the dead of night; the two soldiers manning it had fallen asleep.
A year ago, lawyers for two U.S. pilots in Afghanistan who mistakenly launched an airstrike on Canadian troops, killing four, said Dexedrine, the stimulant they were using to stay awake, had interfered with the pilots' judgment.
And more than 60 years ago, during the Battle of Britain, Allied commanders noticed that Royal Air Force pilots flying missions on little sleep sometimes fought skillfully during combat, but then, returning to their bases, mysteriously lost control of their planes and crashed.
As military planners have turned war into a round-the-clock affair, sleep deprivation and fatigue have proven to be adversaries as deadly as any military foe -- a threat to performance, morale and sometimes survival.
"In the Battle for Britain, when the fighter pilots were going up, they were able to do their dogfights, but a big problem was coming back afterwards," said Jim Horne, who runs the sleep research center at Loughborough University in England. "A lot of planes ditched in the sea because the crew fell asleep. In the heat of the battle, you can do pretty well, but for a sleepy brain to keep going, it has to have increasing levels of stimulation."
As increasingly destructive technologies are placed at the fingertips of troops who are often hours and many miles away from their targets, sleep deprivation's effects on judgment may also increase the risk of civilian casualties. Quick judgments are also needed when troops face guerrilla tactics, as coalition troops are increasingly seeing in Iraq.
"Not paying attention to sleep is tantamount to catastrophe," said David F. Dinges, chief of the division of sleep and chronobiology at the University of Pennsylvania. "It's hard to say would their judgment be worse when they encounter civilians who turn out not to be civilians; the only thing to say is it won't help."
While much attention has been paid recently to the effects of sleep deprivation on troops who go without sleep for a day or two -- such as those in the U.S. convoy that raced toward Baghdad -- scientists are finding that small amounts of reduced sleep over prolonged periods may actually be more devastating to judgment and performance.
The reason is that people deprived of sleep for short periods -- with no sleep or less than four hours a day -- are acutely aware that they are sleep-deprived. Their thinking can slow, affecting judgment. Exactly the same things happen to those who lose an hour or two of sleep a night for eight to 10 days, but because the brain has longer to get used to the feeling, people don't realize that they're impaired.
"If a problem suddenly arises, there is a tendency to solve it one way, and if that fails, to try it again the same way," said Dinges, describing a common problem resulting from prolonged sleep deprivation. "You keep trying the same solution" instead of finding a creative alternative.
At a recent Army training exercise in Southern California, Col. Gregory Belenky, chief neuropsychiatrist at the Walter Reed Army Institute of Research, remembered talking to three Army captains at 4 a.m. They were sleep-deprived and it showed.
"I asked them, 'How are you doing?' They all said, 'Great,' " Belenky recalled. "I pulled one aside and asked what he meant, and he said, 'I'm doing better than those two guys.' But on an absolute scale, they were all in the cellar."
Steady deprivation affects the brain's ability to realize it is sleep-deprived, Belenky explained, adding, "If the measuring device is out, then of course you are going to have problems."
Belenky and other U.S. military researchers have been concentrating on the effects of sleep deprivation in battle, and how to deal with it. Caffeine remains a mainstay for people fighting to stay awake, and Army troops routinely tip back freeze-dried coffee. But pilots and others also routinely turn to drugs such as Dexedrine.
Navy pilots in Iraq are allowed to take 5 mg of Dexedrine, followed by another 5 mg 15 minutes later, and then another 5 mg every two hours after that, said Lt. Mike Kafka, a spokesman for the U.S. Navy Bureau of Medicine and Surgery. The maximum dose is 30 mg a day.
The Air Force allows twice as much each day, said Betty-Anne Mauger, a spokeswoman. The standard single dose is 10 mg, she said, and most pilots do not take more than 20 mg on a single sortie.
Using the drug is voluntary, depends on mission needs, and must be authorized by local commanders, Mauger said. But some military personnel, including those charged with firing on the Canadians in Afghanistan, have said they felt pressured to take the drugs.
The military is also studying the use of Provigil (chemical name modafinil). At the U.S. Army Aeromedical Research Laboratory at Fort Rucker, Ala., psychologist John Caldwell had six pilots fly simulators while depriving them of sleep for 40 hours -- from 7 a.m. one day to 11 p.m. the next. Some were given modafinil, others dummy pills.
The pilots were asked to fly at fixed altitudes, speed and directions, and a computer tracked them. All the pilots did well until 5 a.m. the second day, when normal circadian rhythms made them feel sleepiest. Then the pilots given the medicine did much better.
"Their flight performance under modafinil was almost as accurate as when they were well-rested," Caldwell said.
Unlike those using stimulants such as Dexedrine, the pilots did not report feeling hyper -- they just felt alert. But they had to be given high doses to function properly, and Caldwell warned that the drug is not a way to cheat sleep altogether.
"This drug works very well in the short term, but if people take the next logical step and say, 'Therefore, I can just forget spending all this time in bed and use this drug instead,' you have a much different use that has not been tested and may in fact be unsafe," he said in an interview last year.
Increasingly, however, the cutting edge of military sleep research is not focused on chemicals, but on finding creative ways to make time for troops to sleep, because the more complex effects of sleep deprivation on judgment and creativity cannot be addressed with stimulants or even a few days of regular sleep. Cognitive performance degrades by about 25 percent with every 24 hours of sleep deprivation, said Nancy Wesensten, a research psychologist at Walter Reed.
Even a 30-minute nap each day can lessen the cognitive decline to about 18 percent, she said: "Our advice is to nap early, nap often, sleep as much as you can because any sleep is better than no sleep."
washingtonpost.com |
