I saw that too. When I lost in tournaments I could have made up lots of reasons, and there were certainly times I was extremely tired, but when you play to win you don't make excuses. Get the rest you need, study hard, and if you lose suck it up and look for a brighter day. There is always a reason you lost - it's the one you use that defines your character.
Well said.
Kasparov was an endurance monster when he was younger (best displayed in his marathons with Karpov), and it could very well be that he has simply just lost his edge. I'm sure it must be frustrating, especially since many - not I - consider him the greatest grandmaster of all time. But if he can't take the heat, he should retire. Playing at a very high level into middle age is not very common for players of his calibre; Emmanuel Lasker was one glaring exception.