Tuesday, June 18, 2013

Sleep Times: BodyMedia vs. Zeo

Most of those wrist-style activity monitors try to tell you how well you slept, but I’ve found the technology isn’t particularly accurate. Lately I’ve been trying the BodyMedia FIT armband, which also claims to tell sleep times.  But how accurate is it?

Here are my numbers after a week of wearing both devices.


The bold lines are from BodyMedia and represent the time spent lying down (which should be pretty accurate) versus actually sleeping (which depends on BodyMedia’s algorithms for detecting when sleep starts, and may not be very accurate). The other, non-bold lines are from Zeo, the headband device from the (sadly) now-defunct Zeo Inc, which is clinically proven to be about 80% accurate.

The good news is that the two devices seem to roughly agree, at least on overall sleep times. For that, BodyMedia is pretty good.

BodyMedia also computes another measure they call sleep efficiency that is simply the ratio between the time it thinks you’re in sleep versus the total amount of time spent lying down. Unfortunately, I found no correlation between this and the more meaningful Zeo-calculated sleep phases: REM, deep, or light.

Our bodies are motionless during the REM sleep phase, as muscles are turned off, and we move again when the REM phase is finished. These regular movements throughout the night usually correspond with sleep transitions, which the armband accelerometer can in theory detect, but I couldn’t find that information in the BodyMedia. Other accelerometer-based devices use these movements to guess at when a REM phase began or ended, so conceivably BodyMedia could add that information in the future; or perhaps they’ve considered it but concluded it wasn’t accurate.

Bottom line: BodyMedia is okay as a measure of overall sleep times, but won’t tell you much more.


Monday, June 17, 2013

Why I’m skinny

I weigh about the same today as I did in college: 160 pounds. In my entire life I’ve never weighed more than 170. Maintaining my weight has been effortless: I eat pretty much whatever I like, whenever I want, and in whatever quantity suits me at the time.  I know, I know, this is not normal and I should be thankful.  The vast majority of people, especially past middle age, seem like they have to starve themselves to keep from piling on the pounds.

Why?  I’m not particularly athletic. Although I don’t think of myself as sedentary per se, I’m hardly the type who does regular biking or jogging.

It might be genetic, but it’s hard to say.  My 23andme results suggest, if anything, I have the opposite problem (72/100 vs 64/100 for people like me).  On the other hand, I have the GG marker for rs925946, which puts me at lower odds, but who knows.  Most of my relatives are on the thin side, but we have our share of porkers too. I doubt my DNA explains everything.

One of my favorite theories is that I’m host to a benevolent microbiome, a colony of bacteria in my digestive system that processes food as I eat it, to prevent me from becoming either too skinny or too fat. But I’ve been hospitalized with some powerful antibiotics that probably killed off whatever beneficial bacteria I have, so that’s not persuasive either.

That leaves the most obvious possibility – that I just don’t eat enough – but I’ve never proven that objectively. Until now.

For the past week I’ve been wearing the BodyMedia Fit, a $90 simple and non-obtrusive armband that’s so light it’s easy to forget I have it on. Using four hi-tech sensors, it calculates my metabolism with 92% accuracy compared to the Gold Standard lab equipment. To track my food intake, I use MyFitnessPal, a (free) iPhone app with a huge database of food types (and super-handy UPC code scanner) that makes it easy to enter what I ate each day.

Here are the results:


The bottom line is that I’m thin because I don’t overeat. Apparently my metabolism is set to burn off whatever comes in, which turns out to be well within the range of what it takes to stay thin.

I’m not a weight loss expert, and this is not a testimonial for how to lose weight. Everyone is different, and my results probably won’t help you. But if you want to understand what your body is doing – the first step toward making any changes – then I highly recommend getting a device like this one to understand your metabolism objectively.

Incidentally, a good follow-up question is why I don’t feel hungry. I don’t think weight issues can be solved with self-control: diets fail in the long run if they depend on willpower. Seth Roberts always has thoughts about this that intrigue me and I’ll spend more time thinking about that in the future.

[Placeholder: I’m writing up many more details, including the raw data, about my week with BodyMedia and I’ll post a link here when I’m finished]

Monday, June 10, 2013

Thoughts about WWDC 2013

My takeaways from today's WWDC announcements (in no particular order):

The UI changes for iOS7 are gorgeous, of course, and I can't wait to make the switch.  I wonder how long it'll take for developers to make the switch too. Many (most?) apps will look ancient until they upgrade to the new, flatter, look; even if the OS does most of the work for free, you can't change this much UI without making older apps look, well, old.

I see Apple finally deprecates the 3GS, but is hanging on to the iPad2. No hints, none whatsoever, about future hardware.

That first (and only) third party demo, of Anki Drive, had the potential to be very cool (hardware! and iOS! from robotics experts! ) but it disappointed, and not just because of the long delay as the company CEO tried to get it to work. Now that hardware is the new software, I'm expecting (and seeing!) some products we could only dream about in the past, so I was expecting a lot more than just another real-life game, however cool that might be. 

It's nice to see more Chinese-specific features, like the overdue Tencent Weibo integration. Looks like there will be a built-in Chinese bilingual dictionary, which is handy but a little odd to compete so directly with excellent third parties. I wonder if there'll be other dictionaries too.

I saw a new Scan API, which I hope means OS-level support for reading QR and maybe UPC codes.

Tags in OSX are a great new feature I'll use a lot, though I hope the file system embeds the tag in the document itself, so it'll work cross-platform.

There's a new "location beacon" feature in iOS7 that looks like a low-power way to let devices tell the phone that they're nearby.  I see it's supported by a new "Core Bluetooth" framework that should make it much easier to build apps to talk to all those new hardware devices that are coming.

Other features, like iCloud keychain or the new Safari features mostly just replicate functionality we've long had from third parties. I didn't see much to tempt me to switch, especially since third parties (like 1Password) are likely to quickly rev themselves to run on top of whatever new functionality Apple adds.

The iWork in the cloud, plus the promised rev of these apps later this year, is big news for Microsoft Office. As always, compatibility -- with Office and with Windows -- is a big issue, so running in the browser is the a great way to solve that.

My overall impression is that Apple continues to plod away with reasonable, incremental improvements to their platforms. Not much here is as revolutionary as some of the really big announcements we saw at recent WWDCs (iPhone 4, iCloud, Retina, etc.) but that's okay by me: I'll be upgrading as soon as I can.

Apple Developer


Sunday, June 02, 2013

The future of college

College is such a critical part of modern life that sometimes we forget the difference between “college” and “education”.  Now that my children are closing in on that age, I’ve been thinking about it more.  How is college changing? How can I ensure my kids get the right education?

There are plenty of books (and seminars and consultants) that explain how to get into top colleges, but I don’t really want a how-to manual (maybe it’s my liberal arts education :-). This book, a well-written summary of the bigger and more important trends, was exactly what I needed. The author, Jeffrey Selingo, is a long-time editor of the Chronicle of Higher Education, so his natural audience is people in the academic community, but I found it to be a good overview for interested parents too.

Higher education is in the midst of one of its biggest transformations ever.  Maybe you don’t need to worry just yet If you’re a tenured professor at a reasonably good school, but frankly if you’re just starting to consider a career in academia, you better think carefully because the reset that universities are undergoing will almost certainly make jobs in the Ivory Tower very different just a few years from now. Clay Christenson (The Innovator’s Dilemma) says the disruption is so big that in fifteen years half of universities will be bankrupt.

Technology is the immediate driver of urgency, but as Selingo notes, the problems in higher education are deeper and result from decades of societal attitudes and government policies that focus on the degree itself, as though no dollar amount is too much to justify additional spending on college.

It’s a vicious cycle.  See Bennett’s hypothesis:  “increases in financial aid in recent years have enabled colleges and universities blithely to raise their tuitions, confident that Federal loan subsidies would help cushion the increase”.  Academics will tell you the evidence for this is controversial, but to me it seems self-evident when you look at the rise of “resort colleges” with their expensive – but to immature 18-year-olds, appealing – amenities. When it can easily cost $200K to send a kid to a four-year college, there had better be a lot more value than free ice cream trucks (true story: Hill Point University in North Carolina uses that as one of its many gimmicks incentives  to persuade trick high school seniors into getting their parents to pay the outrageous tuition).

It’s not just tuition prices that are going up, even beyond whatever Baumol’s cost disease predicts. There’s grade inflation of course (did you know that 91% of Harvard students graduate with honors?)  but also an inflation in degrees themselves: with so many low-quality college degrees, it’s getting to the point where you need a master’s degree to stand out, with almost 700K awarded in 2009.  As Selingo writes (p10), "The number of people with a master's degree is now about equal to those with at least a bachelor's degree in 1960...it's probably only a matter of time before the doctorate is the new master's degree".

But the same forces that disrupted the music industry, then journalism, are now coming to universities, and for a similar reason: much easier distribution of information. Some of that, obviously, is the rise of online learning (the book goes into details everything from Khan Academy to Coursera), but better information affects more than just the learning itself. 

For example, it’s much easier to find a good college using several amazing new online resources: Naviance, the excellent detailed database of colleges which most good high schools already subscribe to, and ConnectEDU, which uses a student’s academic record to predict the best fits for colleges and majors. I think resources like this are much more valuable than the newly-fashionable parent-child college tours, which are really more of a family bonding experience than an objective way to learn about colleges.  Who on earth would make a decision based on the impressions of a quick visit – many of which, Selingo notes, are now guided tours put together by the same people who plan experiences at Disneyland.

Information is causing another disruption, thanks to new transparency about the the true ROI for individual colleges and majors. Virginia law requires its colleges to to publish data about the salary earnings of their graduates. In other states, even when colleges don’t want that information published, the company Payscale ranks schools using their extensive data about starting as well as mid-career salaries of their alums. The results are not good news for many schools, and you can see why a shakeout is long overdue.

If you or your kid are one of the few (one out of five, according to psychologist William Damon) who knows what they want to do in life, the coming changes to higher education will seem natural and overdue. For other kids, though (and their parents), the information in this book is indispensible: see his suggestions about overseas study, time off before/during college, preparing better in high school.

My college education, as wonderful as it was for me, will seem quaint and largely irrelevant much faster than we think. This book is a great introduction to how it will change.