[ncphillips]

It's been done, and math + running wins. Check out Tony Schwartz the Power of Full Engagement. In it he talks about how you can't just go go go at the thing you want to get good at, you have to take breaks and do completely unrelated things, like running. If you don't, you'll burn out.

[mathattack]

This makes intuitive sense. One of the best bug-fighting techniques is walking away for a little bit.

[flagnog]

way back in the dark ages, before the Playstation and XBox and Nintendo, I conducted my own empirical studies using coin-operated arcade games. I found that after a couple of hours, my reflexes plateaued, then degraded. I had to go do something else for a couple of hours before I could come back and do better.

[rmk2]

Another really easy way: I have a simply memory game on my phone, 6x4 fields. If it is too late or if I am tired, I will make more mistakes and take longer to memorise things. On the other hand, I can turn and solve it much more quickly when I am fresh and well-rested. Also, if I play a number of them at a time, they start to run together, again resulting in worse results.