Exercise and Its Confounds: The London Bus Study

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.

Passengers entering a London bus in the 1940s
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.

Science in Action: Why Did I Sleep So Well? (part 15)

Yesterday I went to San Francisco early in the morning. Because of my discovery about standing and sleep, I had slept very well. In Berkeley, it looked like morning: empty streets, angle of light. I felt jet-lagged: I should have been tired but I wasn’t. On BART, the same mismatch: Everyone looked tired but I was wide awake.

It is taking longer and longer to get enough one-legged standing to generate great sleep. Here’s a graph of how long I’ve been standing: Each point is a different bout of one-legged standing. Most of the points are from bouts where the standing leg was straight or bent (usually straight) but a few of them (“bent leg”) are from bouts where the standing leg was bent the whole time. Most days have two bouts: 1. On the left leg until I get tired. 2. On the right leg until i get tired. I’m pretty sure there’s no effect until it becomes difficult — until the muscles are so stressed that they send out a grow signal. The whole thing is pleasant because I watch TV or a movie at the same time but, as the graph shows, it has become seriously time-consuming.

So I have tested keeping the standing leg always bent. I get tired much sooner (2 minutes versus 20 minutes) but the effect is not quite as strong. Probably because fewer muscles are involved — you use more muscles when you stand on one leg in any possible way than if you stand on one leg in only one way.

I assume there’s a steady-state solution. The more muscle you have the more you lose each day. (Just as the theory behind the Shangri-La Diet assumes that the higher your set point, the fast it falls.) Eventually I should have enough muscle and will lose enough in one day so the exercise needed to merely replenish it will be enough to produce great sleep.

Life Imitates Art School

I had lunch with Lisa Goldberg, an adjunct professor in the Statistics Department at Berkeley. Her application area is finance. She said that people in finance have at least as much contempt for academics as academics do for people in finance. Thorstein Veblen, of course, wrote about the latter — people looking down on useful work — but not the former. Perhaps his views were skewed by being an academic himself. I blogged earlier about how students in each major at a San Francisco art school look down on the students in some other major.

Lisa also said she sleeps well. I was surprised — hardly anyone says that. It turns out she exercises heavily. She swims or runs seven days a week and when she swims, she swims 2000 meters. As a former swimmer, I know that’s a lot. When I exercised, there was no clear effect on my sleep, apart from falling asleep faster. I still woke up too early in the morning. Maybe I wasn’t exercising enough. Anyway, it’s one little data point supporting my conclusions from standing on one leg.

Treadmill Desks

As far as I know, I was the first person to have a treadmill desk. I wanted to be able to stand more easily. I had found that if I stand a lot I sleep better. I reasoned it might be easier to stand a long time if you are walking than if you are standing still.

Treadmill desks are now becoming mildly popular, the New York Times reports. I had nothing to do with this. They were popularized by James Levine, a Mayo Clinic endocrinologist, who believes that calorie burning is a good way to lose weight. I used my treadmill desk for a few years. There were two big problems: 1. The noise bothered my neighbors. The Times article says these desks tend to be placed in common areas, where that would be less of a problem. 2. It was tiring. After one or two years I mainly stood on it and rarely walked on it. Finally I replaced it with a standing-height desk.

The article describes non-weight-loss benefits: Walking makes it easier to concentrate.

“I thought it was ridiculous until I tried it,” said Ms. Krivosha, 49, a partner in the law firm of Maslon Edelman Borman & Brand.

Ms. Krivosha said it is tempting to become distracted during conference calls, but when she is exercising, she listens more intently.

“Walking just takes care of the A.D.D. part,” she said.

Allen Neuringer, a professor of mine at Reed College, found that movement helped him learn. I think an urge to be active builds up during inactivity just as thirst builds up when we don’t drink. Being able to be active while you work gets rid of that distraction — and no doubt is healthier in other ways than sitting all day. I would like to be able to use a computer while I am free to move around the room (or larger spaces) and move my arms, not just walk forward with my hands on the keyboard. I’d like to be able to write this blog post while strolling through my neighborhood, for example.

Thanks to Marian Lizzi.

Science in Action: Why Did I Sleep So Well? (part 13)

When I talk about how standing on one leg has helped me sleep better, the inevitable question is how much standing? After I became sure the standing was making a difference, I started to record the durations. I always stood on one leg until it became a little hard to continue. As my legs have become stronger, this has taken more time, as this graph shows:

During the early days on this graph, I didn’t include time-of-day information. I usually stood on one leg three or four times per day. More recently, I have included time-of-day info and now stand on one leg only twice most days. In all of the cases shown on the graph, I was pulling my other leg back behind me at the same time, stretching the muscles. (If I don’t stretch the other leg, I can stand one-legged much longer.) In the very beginning, I only stood one-legged 2-3 minutes.

I’m sleeping better than any other period in my adult life. My sleep was pretty good before this period but the difference is still huge. Not only am I sleeping better, I suspect I’m also sleeping less (as happened when I improved my sleep by standing a lot).

I suppose one-legged standing counts as “exercise” — that source of so many claimed benefits (longevity, weight loss, less heart disease, etc.). I read today that exercise is supposed to improve your brain. But the differences between what I am doing and what is usually recommended are as large as the difference between the Shangri-La Diet and other diets:

1. Conventional exercise: Requires expanse (for walking) or, usually, special equipment (e.g., gym). Takes one hour or more, when you count changing clothes and showering, not to mention the drive to and from the gym. One-legged standing: Can do almost anywhere. Takes less than 30 minutes, so far.

2. Conventional exercise: Requires discipline if you want a decent workout in a reasonable amount of time. One-legged standing: Almost no pain involved. I can watch TV or read something at the same time.

3. Conventional exercise: Supposed to be aerobic if you want the main benefits. One-legged standing: The opposite of aerobic.

3. Conventional exercise: Some benefits accrue slowly, such as weight loss. Others are hard or impossible to detect, such as longer life. Runners’ high goes away, in my experience. One-legged standing: Benefit clear the next morning. Because I am strengthening muscles I use all the time (when I walk or stand) I notice my vastly increased leg strength all the time.

4. Conventional exercise: You want to get stronger. One-legged standing: You don’t want to get too strong or else it may take too long to get the effect.

5. Conventional exercise: Often difficult to measure increased strength. Hard to measure improvement in swimming, racquetball, or aerobics classes, for example. One-legged standing: Easy to measure increased strength.

6. Conventional exercise: Helped me fall asleep faster, but didn’t solve the problem of too-light sleep. One-legged standing: Utterly solves the problem of too-light sleep.

Could the benefits of conventional exercise have anything to do with the fact that it vaguely resembles one-legged standing?

Directory.

Why Did I Sleep So Well? directory

  1. Initial observation, 9 possible causes
  2. Another possible cause: standing on one foot
  3. Sleep almost great, narrowing possible causes to two.
  4. Sleep great again, narrowing possible causes to two
  5. Sleep great again after only standing on one foot
  6. Someone else gets similar results
  7. Technical details
  8. How long I stand
  9. Eerie coincidence
  10. Patterns of discovery
  11. Comparison to other sorts of exercise
  12. What’s a good dose?
  13. How much I’ve been standing Comparison with conventional exercise.
  14. Two more people get similar results
  15. How long I stand (continued)
  16. Replication details
  17. The amount of time needed stops increasing

Is Childhood Obesity Due to Not Enough Exercise?

As any reader of The Shangri-La Diet knows, I attribute the obesity epidemic to ditto foods — foods that taste exactly the same each time, such as factory food and fast food. We eat a lot more of these foods today than 50 years ago or even 20 years ago.

An alternative explanation of the obesity epidemic that many people believe is too little exercise. People who deal with childhood obesity, in particular, often say the problem is too much TV, too little playground.

If kids are fat due to lack of exercise, more exercise should be a good solution. A new study shows it isn’t. It turns out that giving kids more P.E. doesn’t cause weight loss:

In studies involving nearly 10,000 children, primarily in elementary schools, none demonstrated a reduction in BMI with those who were assigned to the most phys-ed time, compared to those who didn’t have as much.

Via Calorie Lab.

Comparison of Strategies for Sustaining Weight Loss

A recent issue of JAMA has an article titled “Comparison of Strategies for Sustaining Weight Loss: The Weight Loss Maintenance Randomized Controlled Trial”. It reports an experiment that compared three ways to keep from regaining weight you’ve lost.

If you want to lose weight it paints a discouraging picture. It was an very expensive study, 27 authors, five grants. About 1000 subjects. Four years just to collect the data. The whole thing might have taken seven years. Must have cost millions of dollars. Might have cost tens of millions of dollars.

Given the huge expense, surely the subjects got the best possible establishment-approved weight loss advice. They did lose 19 pounds in six months. Here’s how the advice was described in the article:

Intervention goals were for participants to reach 180 minutes per week of moderate physical activity (typically walking); reduce caloric intake; adopt the Dietary Approaches to Stop Hypertension dietary pattern . . . and lose approximately 1 to 2 lb per week. Participants were taught to keep food and physical activity self-monitoring records and to calculate caloric intake.

Shades of Marion Nestle’s “move more, eat less”! Aside from the DASH “dietary pattern,” which was meant to reduce blood pressure, not weight, this advice could have been given fifty years ago. Apparently, those who did the study and those who funded it — who are representative of the larger research establishment, I assume — believe there has been no theoretical or empirical progress since then.

Many fields haven’t progressed in 50 years. Fifty years ago, 2 + 2 equaled 4. The basic principles of thermodynamics and inorganic chemistry were the same then as they are now. Lack of progress in weight loss advice would be fine if the advice actually worked but the whole study derived from the fact that the advice is poor — the weight loss it produces cannot be sustained.

To help people sustain their weight loss, the study compared three methods: 1. Monthly contact. Usually a 10-minute phone call (“with an interventionist”), every 4th month a hour face-to-face visit. Although the article claims this treatment was “practical,” I suspect it is too expensive for widespread use. 2. Encouragement to visit an interactive website. The website helped you set goals, allowed you to graph your results, and had a bulletin board, plus several other features. This was the focus of the whole huge research project: the effect of this website. It could be offered to everyone practically free, except that if the subject didn’t log on after email reminders she got a phone call. 3. “A self-directed comparison condition in which participants got minimal intervention [that is, nothing].”
The personal contact condition was slightly better than nothing. By the end of the study, the website was no better than nothing. And nothing was bad. The subjects regained about two-thirds of the lost weight during the maintenance year and, looking at the weight-versus-time graph, were apparently going to regain the rest of the lost weight during the coming year. Subjects in all three conditions continued to regain the lost weight throughout the year of maintenance.

In other words, this exceedingly expensive study could be summed up like this: We tried something new, it didn’t work. The abstract didn’t face this truth squarely. It concluded: “The majority of individuals who successfully completed an initial behavioral weight loss program maintained a weight below their initial level.”

It’s a Catch-22: Without a good theory, it’s hard to find experimental effects. You’re just guessing. Most of what you will try will fail. Without strong experimental effects, it’s hard to build a good theory. I was in this situation with regard to early awakening. I had no idea what the cause was. It took me ten years of trying everything I could think of, dozens of possibilities, before I managed to find something that made a difference. From that I managed to build a little bit of a theory, which helped enormously in finding more experimental effects.

The people who did this study had no good theory about weight control. Nothing wrong with that, we all start off ignorant. The website they tested was just the usual common-sense stuff. What’s discouraging for anyone who wants to lose weight is how little progress was made for such a huge amount of time and money. If it takes seven years and ten million dollars and a small army of researchers to test one little point in a vast space of possibilities . . . you are unlikely to find anything useful during the lifetime of anyone now alive (or any of their children). The people behind the study also had a poor grasp of experimental design. With 300 people in the website group, it would have been easy to test many website design variations: weight-loss graph (yes or no), bulletin board (yes or no), etc., using factorial or fractional factorial designs. Their study merely showed that one particular website didn’t work. They learned nothing about all other possible websites. They might have been able to say: no likely website will work. They can’t because the study was badly designed. The study cost something like $10 million and that was the statistical advice they got!

The huge expense and the lack of progress in the last 50 years go together. The methodological dogmatism I discussed recently has bad consequences. It leads to studies that are more expensive and take longer. The proponents of the methodological rigidity say they are “better” not taking account of the cost: continued ignorance about health. A better research strategy would be to fund and encourage much cheaper ways of testing new ideas.

Walk and Write at the Same Time

My exercise research suggests our brains work better when we walk. Here’s one way to combine walking and writing:

While working on a paper, which was most of the time, [Niels] Bohr would select an assistant from among the young physicists in Copenhagen. The assistant, affectionately dubbed the victim, was supposed to sit in place while Bohr paced around the room, constantly puffing away at his pip, working and reworking his ideas, talking aloud as the idea took shape, trying and retrying to dictate his sentences to the victim.

From Faust in Copenhagen: A Struggle for the Soul of Physics by Gino Segre.

The modern version may be use of word recognition software with the computer screen on a wall or large TV. You walk back and forth in front of it. I have spent a lot of time writing while walking on a treadmill but it was noisy and tiring. Moreover, it was hard to start and stop and it was monotonous.