Have you considered randomizing your exercises so you could begin drawing causal inferences?
Yes, but I haven't, because what would I measure? I seem to have "more energy" from doing these exercises, but I expect that rating "energy" on a 5-point scale would be as impossible as rating "happiness". I could instead keep a log of things done (which is, after all, the point of having "energy"). Come to think of it, that might be useful anyway.
Is self knowledge through numbers worth the effort? I welcome your stories and recommendations. Thanks!