Minutes of exercise each day, January through October 2009.
Over these 300 days, I exercised an average of 28 minutes a day. The spikes between 60 and 90 minutes are typically days when I played racquetball. The larger spikes in August are from hiking in Alaska.
Unlike amount of sleep, amount of exercise does correlate with some of my outcomes of interest, but maybe not in the direction you would expect. Below are the outcomes where there is a significant or near-significant difference between days when I exercised for 20 minutes or less and days when I exercised for more than 20 minutes, ordered from most significant to least significant.
Only growth is significant at the 1% level. The others are not statistically significant but are close. Some ratings which do not appear to have any relationship to amount of exercise are mood, food quantity, and food quality.
The somewhat surprising finding is that exercise is harmful to all outcomes of interest except one: wakefulness. (And even then it is not a big difference.) More troubling still is that when I look at how exercise affects next-day wakefulness, the effect disappears. So exercise is associated with only a slight boost in my current day wakefulness, but does nothing for next-day wakefulness, and harms everything else.
A popular claim is that more exercise leads to better sleep. I do not track how quickly I fall asleep, but at least as far as total amount of sleep, yes, I sleep more hours on days when I exercised more. But that is a bad thing. I do not have trouble sleeping; I have trouble getting my ass out of bed. And if exercise does anything, it makes me stay in bed longer than I want.
If there is one outcome I care most about, it is the very subjective rating of the quantity and quality of all the things I learned and experienced combined into a single measure I call 'growth'. It turns out this is the only measure significantly associated with exercise, and not in the direction I would like. The negative direction of the relationship makes intuitive sense, but I was not expecting the magnitude of the difference to be so large. Here is my attempt to explain it: If I play racquetball for only an hour, the time investment is often more like two hours because there is the time to prepare, getting there, then coming back and showering, changing, etc. So right away exercise takes away a quality chunk of hours with which I could have been productive. But more than that, on days when I exercise I often have a greater desire to just relax, because "I owe it to myself".
Up until now, you might think I am making the case that exercise is a big time-suck to be avoided. I am not at all. Knowing how exercise relates to my other ratings is interesting, but I will not change my behavior as a result. Although racquetball might make me less productive, it has other benefits which I think more than compensate for that lack of productivity: I am healthier because of it, it is a social experience, I like the feeling of getting better with every match I play, and most of all it is just so amazingly enjoyable to strategize, adjust to opponents' weaknesses, enter a state of flow, and to hit the perfect 'Z' serve.
Bottom-line: At least for me, exercise is negatively associated with things like productivity, sleep, and even satisfaction, but I continue to do it either because I am stubborn and irrational or because the benefits are more than what is captured in my data.
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Earlier:
Sleep
Weight
The evolution of tracking myself
