I'm still playing internet chess. I managed to get my rating over 1200, but for the last couple of days, I have lost just about every match I played (my preference is to play blitz - 2 minutes plus 5-12 seconds per move - for those who understand such things), so my rating dropped back to about 1050.
Now, what was interesting about this was that, due to work, I have been getting up early and getting less than 7 hours sleep per night. One advantage of "being old" is the ability to "step back" and look at what is happening from a more detached perspective (and not take personally a depressing string of defeats!). I was playing people who I ought to be able to beat, but what happened in game after game would be that I would take risks that I hadn't properly thought out - which almost invariably resulted in me losing material and then the game. It didn't matter that I was aware that this was the problem - in the heat of the game, I would look at a position, and think to myself, "How about if I do that?" and then do it - and then lose. About the only game I won out of 10 or so was one where I had made a mistake which should have allowed my opponent to capture my queen, but he didn't see it, and I captured his instead.
I'm sure that research exists that can demonstrate the effect of fatigue on decision making, but it was very interesting to be able to analyse my own experience in this setting - to be a "case study". Hopefully that will inform my perception of myself and my own decision making process in settings that are a bit more critical than an internet chess match.