FM 22-9 Soldier Performance in Continuous Operations (The first edition) was one of the least read manuals in the 1990's Army. Download a copy and find out a lot more about sleep deprivation than you know now and it's effects on combat operations. Consider that we have been in a high optempo since 2001 and what effects has that has had on the force. Some General Officers have been deployed for 4 years, longer than WWII when they didn't have video teleconfrences and unending powerpoint shows. The sleep gap is no joke.