Regarding the claim that you can train yourself to sleep less, you might find this study interesting: http://www.nytimes.com/2011/04/17/magazine/mag-17Sleep-t.h

Regarding the claim that you can train yourself to sleep less, you might find this study interesting: http://www.nytimes.com/2011/04/17/magazine/mag-17Sleep-t.html?_r=0 http://www.nytimes.com/2011/04/17/magazine/mag-17Sleep-t.htm... They had three different groups that could sleep either 4, 6 or 8 hours. Here's the punchline: "after just a few days, the four- and six-hour group reported that, yes, they were slightly sleepy. But they insisted they had adjusted to their new state. Even 14 days into the study, they said sleepiness was not affecting them. In fact, their performance had tanked. In other words, the sleep-deprived among us are lousy judges of our own sleep needs. We are not nearly as sharp as we think we are." So, although you can get used to being sleepy, it's unlikely you're performance isn't being impacted. You could argue that the 2 week study wasn't long enough, but it still seems to show that you can't really judge your own cognitive performance, so any anecdotal evidence to the contrary wouldn't hold much water.