Practice makes tired

Due to an extremely surprisingly small amount of homework, I spent a lot of time in the practice room this weekend. I mostly worked on one piece by Ravel that I am working on for piano right now. I spent far more time practicing in the last few days than I had in any similar period of time before. It was a huge help in learning the piece, but sucked a lot of energy out of me. I found that when people came in to talk to me while I was practicing, I was unable to concentrate on what they were saying, and could hardly keep a conversation going. While I was practicing, I could concentrate extremely well on the piece, but then as soon as I had to think about something else, it was as though a wall had been built up around my brain to protect it from extraneous thoughts...

Just some observations.