Decision fatigue and workout planning


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- Alex Hutchinson (@sweatscience)


John Tierney has an interesting article in New York Times Magazine about the concepts of “decision fatigue” and “ego depletion” — the idea that the simple act of making decisions, no matter how seemingly trivial, uses of a finite store of willpower. The idea seems intuitively obvious, but the studies he describes are fascinating and unexpected.

For example, prisoners appearing before Israeli parole boards have a 70 percent chance of getting parole if they appear first thing in the morning, but just a 10 percent chance if they appear late in the day: the judges are tired of making decisions, and react unconsciously by sticking to the default option. Lots of different factors affect decision fatigue, including glucose levels in the brain — so the chance of parole drops to 20 percent by midmorning, then rises to 65 percent after the midmorning break, during which sandwich and fruit is served to the judges. Just before lunch, probability is back down to 10 percent, then back up to 60 percent immediately after lunch, and so on.

It’s a long article, and I don’t want to oversimplify by summing up — but this is the passage, near the end, that I found interesting in the context of exercise:

“Good decision making is not a trait of the person, in the sense that it’s always there,” Baumeister says. “It’s a state that fluctuates.” His studies show that people with the best self-control are the ones who structure their lives so as to conserve willpower. They don’t schedule endless back-to-back meetings. They avoid temptations like all-you-can-eat buffets, and they establish habits that eliminate the mental effort of making choices. Instead of deciding every morning whether or not to force themselves to exercise, they set up regular appointments to work out with a friend. Instead of counting on willpower to remain robust all day, they conserve it so that it’s available for emergencies and important decisions.

I think this is a really important point. Strangely, I’ve found it’s much easier for me to stick to a routine where I run every day than to run six or five or four days a week. In terms of my current fitness goals, six days would be plenty and possibly even preferable to seven — but as soon as you introduce that element of choice, every morning suddenly gets much more complicated. Should I take my day off this morning? How tired am I? Is it going to rain? How do I expect to feel later in the week?

When I was training more seriously, a periodic rest day was much more important in order to get adequate recovery — but even then, I found it much easier to schedule a regular rest day (I took every second Monday off) than to make those decisions on a day-to-day basis. It wasn’t a question of being too obsessive to take an unplanned day off — it was simply too much mental effort to have to decide every morning “Am I running today?” There’s a great passage in Once a Runner about that idea (unfortunately I don’t have my copy here, or I’d quote it), how you have to make the decision about what you’re going to do, then close the book and just do it, rather than revisiting the decision every time it gets hard, or every time you wake up in the morning. (Of course, you still have to allow a certain amount of flexibility: sometimes it really is smarter to take an unplanned day off — but that’s different from having a regular weekly day off that can be taken any day of the week.)

When people ask me for advice about planning an exercise program, that’s one of the things I emphasize. Being flexible and fitting in exercise when it’s convenient may sound good in theory. But for me, at least, my will power isn’t strong enough to do that on a regular basis. Better to make the decision in advance, then just follow my own orders when it’s time to workout.

9 Replies to “Decision fatigue and workout planning”

  1. Thanks Alex. Very interesting. Maybe this is why I question–without any evidence–the idea we all constantly restate about varying exercise routines and routes. I suspect that many of us have one simple, best running route, for example, and that we repeat it much of the time. (Either that or I’m the weird, anal one.) I think doing the one route over and over is easier than constantly picking out new ones. In terms of the exercise frequency and load we’re trying to attain. Amby Burfoot

  2. Perhaps this decision fatigue in part explains many athletes’ desire to follow an online program or hire a coach. The decisions are made for you and it is therefore much easier to just DO rather than plan and decide.

    Thanks for the article.

  3. @Amby and @Calvin: Thanks for the comments, and I agree with you both.

    In terms of running routes, it definitely makes sense — though of course there are multiple factors that would play a role, including personality traits. Personally, I prefer running the same route over and over (I think in every place I’ve lived over the past 20 years, I’ve had no more than two regular running routes from home). In other contexts, I enjoy exploring and seeing new places — but to make it easy to get out the door and do my run, I don’t want to add any additional cognitive load (like deciding where to go).

    Same goes for coaching. I’ve been running at a high level and reading about the sport for long enough that I’m pretty confident in my ability to put together a training plan. But when I’m in Toronto, I’m happiest heading to the workouts that my longtime coach, Ross Ristuccia, runs. It’s not that I expect there to be specific magic in those workouts. If anything, it’s the opposite: I don’t think the details of day-to-day workouts are particularly important, so I’m happiest removing yet another cognitive burden from my load by relying on Ross to make the choice among the infinite possible combinations of distance, pace and recovery. And while I’m in Australia (where I don’t have a coach) I’ve actually spent some time playing with the SmartCoach software that Amby created, which spits out a personalized training plan based on your goals, current level, and other parameters. Again, it’s not that I think the workouts are magic — it’s just nice to be told what to do!

    Of course, there are other distinct benefits of being coached by a human. Having someone who can watch your training objectively and make decisions in real time about when you need to rest and when you can push a little harder is probably the biggest benefit for elite endurance athletes (who already have enough expertise to write down a perfectly good training program on paper).

  4. Great post! I’ve worked out regularly for more than a decade. Two months ago I started planning out my workouts (including yoga sessions and morn pushups) a week ahead of time. I’ve not missed a work out since. This post hit home for me the importance of continuing this habit as I get older and family responsibilites increase. Keep up the good work!

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