A study just out of Duke has some findings that are important to all of us. When we are sleep deprived, even moderately so, it changes the way we make decisions. We tend to be more optimistic and therefore take greater risks to achieve benefits that seem better than they really are. This is why Vegas casinos make so much money late at night. But it could also be a problem for anyone in business who gets to work in the morning still sleepy and has to make important decisions. The gains will seem better than they really are and you will take more risks.
What makes it worse is that caffeine and other stimulants don’t help. They keep you awake, but don’t fix your decision making. So in fact, you are even worse off because being awake allows you to get more done, so you will make more bad decisions than if you just stay sleepy.