Category: exercise

More Sitting, More Diabetes: New Meta-Analysis

Seth Roberts9 Comments

The first evidence linking exercise and health was a study of London bus workers in the 1950s. The drivers, who sat all day, had more heart attacks than the ticket takers on the same buses, who were on their feet all day. It was a huge advance — evidence, as opposed to speculation. The results were taken countless times to imply that exercise reduces heart attacks but epidemiologists understood there were dozens of differences between the two jobs. For example, driving is more stressful than ticket taking. Maybe stress causes heart attacks.

The first time I learned about this study, I focussed on two differences. The ticket takers were more exposed to morning sunlight (on the top deck of double-decker buses) and they were on their feet much more. Maybe both of those things — morning sunlight exposure and standing a lot — improve sleep. Maybe better sleep reduces heart attacks. The London data were not consistent with the claims of aerobic exercise advocates because the ticket takers did nothing resembling aerobic exercise.

Later I discovered that walking an hour/day normalized my fasting blood sugar levels — another effect of “exercise” (but not aerobic exercise). I had data from only one person (myself), but it was experimental data. The treatment difference between the two sets of data being compared (no walking versus walking) was much sharper, in contrast to most epidemiology. I am sure the correlation reflects cause and effect: Walking roughly an hour/day normalized my blood sugar. This wasn’t obvious. The first thing I tried to lower my fasting blood sugar levels was a low-carb diet, which didn’t work. I discovered the effect of long walks by accident.

A recent meta-analysis combined several surveys that measured the correlation of how much you sit with other health measures. The clearest correlation was with diabetes: People who sit more are more likely to get diabetes. Comparing the two extremes (most sitting with most standing), there was a doubling of risk. Because people who stand more walk more, this supports my self-experimental findings.

I found pure standing (no walking), or leisurely (on-off) walking, did not lower fasting blood sugar (which I measured in the morning). After I noticed that walking an hour lowered blood sugar, I tried slacking off: wandering through a store or a mall for an hour. This did not lower fasting blood sugar. I concluded it had to be close-to-nonstop walking. Someday epidemiologists will measure activity more precisely — with Fitbits, for example. I predict the potent part of standing will turn out to be continuous walking. Long before that, you can see for yourself.

 

 

 

 

 

 

 

 

 

 

Let Them Get Sick (running)

Seth Roberts14 Comments

I wrote recently about how our health care system resembles a protection racket. In a protection racket, you or someone else threatens people so that you can make money protecting them. Modern health care, especially in America, ignores prevention. It says let them get sick. Let the general public get sick so that we (health care providers) can make money treating them.

The profitability of let them get sick is illustrated by some numbers in Run Barefoot Run Healthy, a new book by Ashish Mukharji (who gave me a copy). Ashish has run several marathons. Before he started running barefoot, running caused all sorts of problems. To deal with them was costly:

  • Two or three pairs of orthotics (a type of insole): $200-$300 each.
  • One MRI, for what turned out to be ITBS (Iliotibial Band Syndrome, a thigh injury): around $1,000.
  • Twenty or more deep-tissue massage treatments for ITBS: around $80 each.
  • Corns removed (twice): $500 per treatment.
  • Twenty or more sessions of physical therapy for ITBS and Achilles tendonitis: $100-$250 per session.
  • Several visits to orthopedists and podiatrists: $150 per visit.
  • Cortisone injection for plantar fasciitis: $200.

Since he started barefoot running (3 years and 2 marathons ago), he has incurred no (zero) running-injury expenses. Interviews with other barefoot runners convince him this is typical. Long ago a runner friend of mine told me everyone who runs eventually hurts themselves. The truth of this was confirmed many times by runners I met after she said this. Now it appears she was right because all the runners she and I knew wore shoes.

I started barefoot running/walking on my treadmill a year ago. I have never had running injuries (probably because I walk — uphill fast — much more than run). Going barefoot saved time. During the first few months, I got four or five cuts (actually, splits) on the sides of my feet. The skin was split by downward pressure. The cuts made ordinary walking (in shoes) a little unpleasant. I did nothing about them. They healed and have not recurred.

A better health care system would have discovered the damage caused by running shoes long ago. We are lucky to live when personal scientists such as Ashish can figure out the truth themselves and tell others.

Assorted Links

Seth Roberts1 Comment

My Treadmill Desk

Seth Roberts5 Comments

In 1996 I put a treadmill in my office so that I could work standing up. My goal was better sleep (the more I stood, the better I slept), not weight loss (the usual reason for a treadmill desk). It was hard to walk a lot. Mostly I stood still. It was noisy, too — my neighbors complained. When the treadmill broke I didn’t replace it.

Now I walk on a treadmill for different reasons: to lower blood sugar and learn Chinese. Above is my current setup. I use the laptop to study Chinese (using Anki) or watch TV or movies. Studying Chinese while walking is much easier than studying Chinese while standing still or sitting. I have used flashcards but Anki (shown on the computer screen) helps space repetitions optimally. The headphones (Bose noise-reduction) are for TV and movies. I don’t need them for Anki.

Is It Obvious to Walk to Control Blood Sugar?

Seth Roberts8 Comments

I discovered via self-tracking that I could get my fasting blood sugar much closer to optimal by walking an hour per day. This took me a year to figure out and I discovered it by accident. Phil commented that I could have learned the same thing more quickly by searching websites or asking my doctor.

Whether I was rediscovering the fairly obvious is important to me. This website by Janet Ruhl, who has diabetes, is named “How to get your blood sugar under control”. Its advice says nothing about exercise, much less walking. Here’s one reason why:

I [Ruhl] currently control my own diabetes using a fairly low carbohydrate diet and very low doses of fast acting insulin at meal time. . . . At one point I exercised daily for a year and got my body fat down to 24%, which put me into the “Fitness” category for a woman my age. Despite what my doctors had told me, weight loss and intense fitness didn’t do a thing for my blood sugars, which got worse.

Emphasis added. I too did recommended amounts of aerobic exercise. I too found my blood sugar was nevertheless unpleasantly high. The usual recommendation of aerobic exercise may make it less likely you will do the long low-intensity exercise (ordinary walking) that my results suggest works. You may think: I’ve already exercised. I’m tired.

“Be very paranoid about any new drug.”

Assorted Links

Seth Roberts3 Comments

Thanks to Peter Couvares and Casey Manion.

Assorted Links

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  • “Your body’s resistance to an activity isn’t an obstacle to be overcome, it’s a message that you’re being an idiot, just like when your hand hurts after you punch a wall. The right solution isn’t to start punching the wall harder, it’s to look around for a tool to help you do the job . . . With losing weight, the key is things like the Shangri-La Diet.” Aaron Swartz argues that if something needs a lot of will-power to do, it’s a mistake. I agree.
  • Reed Hundt on “Bandwidth, Jobs, and the Future of Internet Freedom”.
  • Art DeVany interviewed on Econtalk. Agrees with Aaron.
  • In China, “what censored actually means”. “One day last summer, an anonymous member posted something on a Baidu forum devoted to the online game World of Warcraft, and it became an Internet meme: Jia Junpeng, your mother wants you to go home to eat. The cheeky, mysterious sentence received seven million hits and 300,000 comments on the first day. . . . Around the time the post originally appeared, a famous blogger named Guo Baofeng was arrested [by the Mawei police] for posting allegations of an official cover-up in the brutal rape of a 25-year-old woman named Yan Xiaoling in Mawei, a district in the city of Fuzhou. She later died of her injuries. . . . Bloggers began calling on people to send postcards to the Mawei police: Guo Baofeng, your mother wants you to go home to eat. Similar messages sprouted on bulletin-board sites. A few days later, Guo was released.”

Thanks to Evelyn Mitchell.

Optimal Daily Experience

Seth Roberts15 Comments

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. T he 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.

Boring + Boring = Pleasant!?

Seth Roberts23 Comments

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.

Obesity and Your Commute

Seth Roberts10 Comments

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.