Seth’s blog

Everyone knows about RDAs (Recommended Daily Allowances) of various nutrients. In a speech to new University of Washington students, David Salesin, a computer scientist, advised them to “maintain balance” by getting certain experiences daily:

• something intellectual [such as a computer science class] (not so hard in college);
• something physical (like running, biking, a team sport);
• something creative (like music, art, or writing); and
• something social (like lunch with a friend).

This served him well in college, he said, and he continued it after college.

I think he’s right — we need certain experiences to be healthy just as we need certain nutrients. My rough draft of such a list would be this: 1. Social. 2. Physical. Nassim Taleb’s ideas about exercise seem as good as anyone’s. This is really several requirements, for different sorts of exercise. 3. Travel. About an hour per day. 4. Hunger. The data behind the up-day-down-day diet suggest we should experience a substantial amount of hunger every week. 5. Face-to-face contact in the morning. About an hour. 6. Morning sunlight. An hour? 7. Being listened to. I suspect the therapeutic value of psychotherapy derives from this. I believe this is one reason blogging is popular — it provides a sense of being listened to. 8. Being helpful. 9. Being recognized as having value. Blogging helps here, too. 10. Being part of a group effort, something larger. Of course #1 (social) and #5 (morning faces) can come from the same experience, and so can #2 (physical) and #3 (travel). I wouldn’t say we need #7-#10 every day but perhaps several times per week.

I might add two more things: 11. Learning. After I started studying Chinese via Anki/treadmill, I started to sleep better. It wasn’t the treadmill; that wasn’t new. Several studies have found that people sleep more when they are learning intensely. After I became a professor, instances of concentrated learning — such as learning to use R — became rare. I remember how good they felt. How intense learning could go on throughout your life during the Stone Age isn’t obvious, however. Presumably all the experiences we need to be healthy were easily available then. 12. Foot stimulation. In a Beijing park, I came across a cobblestone track about a hundred yards long. Walking on it is supposed to be beneficial. I took off my shoes and socks and tried it. I was astonished how painful it felt — but day by day I could stand on it longer. This is a topic for another post but of course in the Stone Age people got a lot more foot stimulation than anyone reading this. Commercial cobblestone track. Thanks to Tim Lundeen for reawakening my interest in this.

Fact 1: For the last few weeks, I’ve been studying Chinese using a flashcard program called Anki. It’s an excellent program but boring. I’ve never liked studying — maybe no one does. Fact 2: I’ve had a treadmill for a very long time. Walking on a treadmill is boring so I always combine it with something pleasant — like watching American Idol. That makes it bearable. I don’t think listening to music would be enough.

Two days ago I discovered something that stunned me: Using Anki WHILE walking on my treadmill was enjoyable. I easily did it for an hour and the next day (yesterday) did it for an hour again. The time goes by quickly. Two boring activities, done together, became pleasant. Anki alone I can do maybe ten minutes. Treadmill alone I can do only a few minutes before I want to stop. In both cases I’d have to be pushed to do it at all. Yet the combination I want to do; 60 minutes feels like a good length of time.

I’ve noticed several related things: 1. I could easily study flashcards while walking. This was less mysterious because I coded walking as pleasant. 2. I can’ t bear to watch TV sitting down. Walking on a treadmill makes it bearable. This didn’t puzzle me because I coded TV watching as pleasant and sitting as unpleasant (although I sit by choice while doing many other things). 3. I have Pimsler Chinese lessons (audio). I can painlessly listen to them while walking. While stationary (sitting or standing), it’s hard to listen to them. 4. When writing (during which I sit), it’s very effective to work for 40 minutes and then walk on my treadmill watching something enjoyable for 20 minutes. I can repeat that cycle many times. 5. Allen Neuringer found he was better at memorization while moving than while stationary. 6. There’s some sort of movement/thinking connection — we move our arms when we talk, we may like to walk while we talk, maybe walking makes it easier to think, and so on.

You could say that walking causes a “thirst” for learning or learning causes a “thirst” for walking. Except that the “thirst” is so hidden I discovered it only by accident. Whereas actual thirst is obvious. The usual idea is that what’s pleasant shows what’s good for us — e.g., water is pleasant when we are thirsty. Yet if walking is good for us — a common idea — why isn’t it pleasant all by itself? And if Anki is good for us, why isn’t it pleasant all by itself? The Anki/treadmill symmetry is odd because lots of people think we need exercise to be healthy but I’ve never heard someone say we need to study to be healthy.

The evolutionary reason for this might be to push people to walk in new places (which provide something to learn) rather than old places (which don’t). To push them to explore. David Owen noticed it was much more fun  for both him and his small daughter to walk in the city than in the country. He was surprised. When I drive somewhere, and am not listening to a book or something, I prefer a new route over a familiar one. If I am listening to a book I prefer the familiar route because it makes it easier to understand the book.

Maybe the practical lesson is that we enjoy learning dry stuff when walking but not when stationary. Pity the 99.9% of students who study stationary. Ideally you’d listen to a lecture while walking somewhere, perhaps around a track. Now and then I’ve interviewed people while walking; it worked much better than the usual interview format (seated). The old reason was I disliked sitting. Now I have a better reason.

In the 1950s — before the invention of BMI (Body Mass Index) — Jean Mayer and others did a study of obesity at a factory in India. They divided workers by how much exertion their job required. Almost everyone, even desk clerks, was thin, with the exception of the most sedentary. It appeared that walking one hour per day (to and from work) was enough to get almost all the weight loss possible with exercise. Doing more had greatly diminished returns. A study with rats suggested the same thing. Bottom line: If you’re sedentary, you can easily lose weight via exercise, which can be as simple as walking to work. If not, it’s hard.

This month GOOD has a kind of update of that ancient study — a scatterplot, each point a different country, that shows percentage of obesity and fraction of commutes that are active (bike or walk). It supports what Mayer and others found — that how you get to work makes a difference. If you fitted a line to the data it would have a negative slope (more obesity, less active commutes). America has the most obesity and relatively few active commutes; Switzerland has the most active commutes and relatively little obesity. The graph also suggests that other factors matter a lot. Although Australia has less active commutes than America, it also has less obesity.

Just as addictive as everyone said. It reminds me of racquetball, which I could play for hours. But racquetball required going to the gym, getting dressed, finding someone to play with, waiting for an empty court, coming home. It might be possible to use my DDR scores as a measure of something.

The Financial Times recently ran an article about Jerry Morris, a London epidemiologist who did the most famous study of the effect of exercise. He compared London bus drivers with the ticket takers on the same buses. The ticket takers got a lot more exercise than the drivers. The health differences between them were attributed to exercise:

“There was a striking difference in the heart-attack rate. The drivers of these double-decker buses had substantially more, age for age, than the conductors [= ticket takers].” [said Morris]

The data were so telling because drivers and conductors were men of much the same social class. There was only one obvious difference between them. “The drivers were prototypically sedentary,” explains Morris, “and the conductors were unavoidably active. We spent many hours sitting on the buses watching the number of stairs they climbed.” The conductors ascended and descended 500 to 750 steps per working day. And they were half as likely as the drivers to drop dead of a sudden heart attack.

Morris found that bus conductors had fewer heart attacks than sedentary drivers

Today, almost everyone understands that physical exercise can help prevent heart disease, as well as cancer, diabetes, depression and much else besides. But on that day in 1949 when Morris looked at the bus data, he was the first person to see the link. He had inadvertently – “mainly luck!” – stumbled on a great truth about health: exercise helps you live longer.

It’s not that simple. There are two big confounds in the study (two other differences between drivers and ticket takers) that surely caused Morris to overestimate the benefits of exercise. One is well-known to epidemiologists: Bus driving is very stressful. Much more stressful than a dozen other equally sedentary jobs. Stress certainly causes heart disease. The other is based on my discovery that standing a lot improves sleep. (The standing needn’t involve movement.) I don’t know if better sleep specifically reduces heart disease but it certainly increases resistance to infection and heart disease seems to have an infectious component.  The ticket takers were on their feet all day, the drivers were not.

You may remember that James Fixx, a famous advocate of jogging, died of a heart attack.

Thanks to Dave Lull.