[Epistemic status: a half-thought, which I started on earlier today, and which might or might not be a full thought by the time I finish writing this post.]
I’ve long counted exercise as an important component of my overall productivity and functionality. But over the past months my exercise habit has slipped some, without apparent detriment to my focus or productivity. But this week, after coming back from a workshop, my focus and productivity haven’t really booted up.
Here’s a possible story:
Exercise (and maybe mediation) expands the effective time-horizon of my motivation system. By default, I will fall towards attractors of immediate gratification and impulsive action, but after I exercise, I tend to be tracking, and to be motivated by, progress on my longer term goals. 
When I am already in the midst of work: my goals are loaded up and the goal threads are primed in short term memory, this sort of short term compulsiveness causes me to fall towards task completion: I feel slightly obsessed about finishing what I’m working on.
But if I’m not already in the stream of work, seeking immediate gratification instead drives me to youtube and web comics and whatever. (Although it is important to note that I did switch my non self tracking web usage to Firefox this week, and I don’t have my usual blockers for youtube and for SMBC set up yet. That might totally account for the effect that I’m describing here.)
In short, when I’m not exercising enough, I have less meta cognitive space for directing my attention and choosing what is best do do. But if I’m in the stream of work already, I need that meta cognitive space less: because I’ll default to doing more of what I’m working on. (Though, I think that I do end up getting obsessed with overall less important things, compared to when I am maintaining metacognitive space). Exercise is most important for booting up and setting myself up to direct my energies.
 This might be due to a number of mechanisms:
- Maybe the physical endorphin effect of exercise has me feeling good, and so my desire for immediate pleasure is sated, freeing up resources for longer term goals.
- Or maybe exercise involves engaging in intimidate discomfort for the sake of future payoff, and this shifts my “time horizon set point” or something. (Or maybe it’s that exercise is downstream of that change in set point.)
- If meditation also has this time-horizon shifting effect, that would be evidence for this hypothesis.
- Also if fasting has this effect.
- Or maybe, it’s the combination of both of the above: engaging in delayed gratification, with a viscerally experienced payoff, temporarily retrains my motivation system for that kind of thing.)
- Or something else.