TALLIL AIRFIELD, Southern Iraq—Bleary-eyed between 15-minute naps, Army Staff Sgt. Frank Kapaun recalled once sleeping atop an armored personnel carrier in a sort of fetal position.
On his knees.
"The way the vehicle was set up, that was the only way to sleep," he said. "When I woke up it felt like somebody had beaten my body with ball bats and chains."
The lack of sleep for some U.S. troops leads to the kind of dreamlike scene that unfolded last week as they pushed toward Baghdad.
Soldiers in a slow-moving convoy kept nodding off at the wheel. Their military vehicles drifted off route, vanishing into a whirling sandstorm until comrades from behind caught up to shake the drivers awake.
For others, such as a B-2 stealth bomber crew that recently completed a mission of more than 30 hours, rushing adrenaline, catnaps and a "go pill" or two can keep them functioning for days.
Researchers have long been concerned about the effect of sleep deprivation on fighting troops. This war may provide one of the toughest tests yet.
Sharply reduced manpower within the armed services in the past 20 years means squeezing higher performance from fewer people. The allied force now trying to capture Iraq is half of what fought to liberate Kuwait in the 1991 Persian Gulf War.
"Certainly, people who are severely sleep-deprived become more passive and relatively apathetic" to potential dangers, said Col. Gregory Belenky of the Walter Reed Army Institute of Research.
A Marine in central Iraq, Lance Corp. Erik Pronold said he had gone about a week without a full night's sleep. During that time, he had been in a foxhole or atop a truck.
"We're on guard duty, and security is important right now," he said. "The toughest time is midnight to 4 a.m. It's totally dark, and we can't use of any light or we'll give away a position. It's also totally silent, and we can't make any noise. It sure feels like a good time to sleep."
No hard rules govern the combat soldier's sleep. Military manuals offer little help: "Try to get at least four hours sleep per day," says one Navy publication, or "catnap when you can, but allow time to wake up fully."
Between the firefights and the whipping sandstorms in Iraq, even naps as short as 10 minutes are recommended.
Air Force and Navy pilots in recent years have been allowed to pop dextroamphetamines, often referred to by brand name Dexedrine, to maintain alertness when flying long operations.
Use of these so-called "go pills" is voluntary and dosages are limited to six pills, or 30 milligrams, in a 24-hour period, a Navy official said.
"Those are a little bonus. They help," said Lt. Comdr. Matthew Gregor on the USS Harry S. Truman in the Eastern Mediterranean. "Take one of those and it feels like you drank maybe three or four cups of coffee. It keeps you going for a little while."
The pills' use was called into question last year in Afghanistan after two American F-16 pilots mistook a training exercise for hostile fire and bombed a group of Canadian soldiers. The pilots had taken small doses of dextroamphetamines, but the drug's role in the episode was never established.
Even when there is time to sleep, it may not be possible. Near the Kuwait border, there is constant vigilance for incoming Iraqi missiles.
"You are afraid to sleep," said Air Force Staff Sgt. Tomsanna Farley, 25, deployed from Patrick Air Force Base in Florida. "You are stuck waiting—you know one is going to come."
The problem is as old as war itself.
Fatigue severely hindered the performance of U.S. paratroopers in the Normandy invasion of June 1944. An Army captain later told author Samuel L.A. Marshall: "They were so beat they could not understand words even if an order was clearly expressed. I was too tired to talk straight. Nothing I heard made a firm impression on me."
Even the most dog-tired troops can perform grunt work, said Maj. Rob Dillon of Yorktown, Pa., who is stationed at Tallil Airfield as a planning and operations officer for the 709th military police battalion. "But if they're tired and you're asking them to call in some grid coordinates (map locations), you run the risk they'll answer you like a babbling idiot."
For Kapaun, 44, of Columbus, Ga., soldiering in the field means relying on a series of those 15-minute naps snatched when time and the movement of war allow.
"But the best cure" for fatigue, he said, "is a good night's sleep in a squishy bed."
(Canon and Schofield are with U.S. forces in Iraq. Montgomery reported from Kansas City. Knight Ridder Newspapers correspondent Sandy Bauers aboard the USS Harry S. Truman contributed to this report.)
(c) 2003, Knight Ridder/Tribune Information Services.