As we watch the progress of the war in Iraq, most of us can only imagine the mind-numbing fatigue that must be affecting the soldiers, sailors and airmen fighting in the gulf.
So how do they keep going in life and death situations and how do commanders know when their men are too tired?
You don't have to be a doctor or a general to realize that an army on the attack has little time for rest. There's the physical demands plus the stress of battle to deal with. Then try sleeping in a foxhole and you can see what rest soldiers do get may not be all that restorative.
Sgt. Gerrold Johnson says they're called "stragglers," anytime there's a movement marching, they're the ones that are obviously fatigued and are in the back of the group.
Determination and adrenaline can compensate some, but eventually fatigue has to degrade performance. In war, that can get you and your unit killed.
Dr. Michael Rosenburg of the JFK Medical Center says it affects how alert and attentive you can be, and that it affects your decision-making ability, as well as how rapidly and accurately you can react.
Stimulant medications such as amphetamines, Ritalin and Provigil are reportedly being used in the gulf to keep troops sharp.
But a commander has to have a better way to tell whether his troops are able to carry out a mission. It turns out the eye movements, such as tracking an object and pupilary reaction time, deteriorate with fatigue.
Dr. Rosenburg says the goal is to correlate those and other measurable things with fatigue and mission impairment.
He says there should be a device that tracks and tests soldiers to decide whether each individual will be able to complete the mission safely and successfully.
Such a device is not available yet.