Commanding a combat unit makes you tired, sometimes fatally so. This has long been known, and the situation has grown worse in the last century with the development of the "combat zone", endless operations and better communications. Commanders often push themselves to the point of exhaustion, while trying to micromanage everything. Experience has shown that a commander, or subordinate (officer or soldier) can keep going for about 72 hours of continuous operations before people start to just nod off. Even though this problem has been well known for generations, and many clever guidelines have been developed to avoid it, you still get groggy leaders and troops after 72 hours. But not everywhere. Avoiding this problem is largely a matter of discipline. The best trained units don't have the problem, instead they have mastered "Battle Rhythm." This was a collection of techniques that scheduled chores in such a way that everyone got as much sleep as possible. That was never enough sleep, but it was usually more than the enemy was getting, and this sort of advantage can be critical on the battlefield.