Skip to content

Quantifying your Fitness

At OSCON last week, I gave a presentation on Quantifying your Fitness. It was well received, and most people were quite amused to see me wandering the conference with 5 fitness devices (6 if you count my iPhone). You’re welcome to check the slides out for more detailed information, but as I suspect most readers are in a hurry this post will be a summary of my findings. In some cases I don’t have all the data, so I’ll note that where appropriate and ask you, dear reader, to pass along the information if you have it. Please keep in mind that while some of these devices provide more or less information, any device that you will use and wear regularly will work great, even if it’s a simpler model. These summaries are just that, summaries. You can check the slides for more detailed information on any of these.

Ok, ready? Let’s go.


Bodymedia Fit

This is something of the gold standard of fitness devices at this time. The calorie estimates track very closely to chest-strap heart rate monitors and this device is approved by the FDA for use in clinical trials of various types. The skin temperature, moisture and three motion sensors collect 5,000 data points per minute, which they combine with some amazing backend algorithms to create a fantastic product. Price wise it’s reasonable, although the subscription price is a little daunting. The main drawback of this device is that it’s just really ugly – it must be worn on the upper arm and looks somewhat like an insulin pump. They are coming out with a new model this month (August 2013) which will look much better and also have an optional heart rate monitor – and it will be usable during swimming, which is a huge boost of coolness for this product. The website is somewhat limited – it will report your nutritional information, for instance, if you use a different application to monitor it; but it isn’t designed to be the input/tracking application for things other than the information from the device itself.


This is the one most people know – it’s a cute little device that you wander around with and it uses motion sensors to track your activity. The website is pretty darned good – you can log food, activities, mood, etc. and it will keep track of those items along with the sensor data. The API is quite strong, and has good developer support – so if you’re looking for a device/API to integrate with your cool game/application/motivational website this is a great choice. The device is easy to use, it syncs automatically when it sees the base or your phone, and it has a cute flower when you exercise. On the other hand, clipping it to your bra means you’ll wash it and have to buy a new one, so I’m on my 5th Fitbit at this point.

Jawbone Up

This device is a wristband which comes in funky colors. The headphone jack connector is supposed to be covered with a matching plastic cover, but I have kittens so as soon as I took the cover off it became one of their toys and I never saw it again. In any case, the motion sensors seem to do a decent job, but syncing by plugging the thing into the headphone jack of your phone just seems like too much effort to me (I’m lazy, so sue me :-) On the other hand Jawbone purchased Body Media recently so I expect great things out of them in the future. Their API is in beta right now, so you can’t really access your data yet… but I expect this to be fixed soon.

Withings Pulse

This device is brand new, and has gotten rave reviews. I’m not exactly sure why… it’s basically a fitbit with a few extra bells and whistles. It tracks your activity well, and has a spiffy touchscreen. You can manually check your heartrate (although I’ve found this to be somewhat twitchy) and tell it you’re going to sleep. You sync it by pushing the button on the device, which activates the bluetooth connection to your smartphone. Anyhow, it’s cool. I just don’t love it. And it doesn’t sync automatically which makes it less awesome than the fitbit. Also the website support and API interaction are pretty limited at this point, but I expect that they’ll get this fixed soon. The Withings App on smartphones does know about the pulse and tracks your activity pretty well.


I love this device. Yes, the charging cradle is a pain to use. The battery only lasts a few days, when I remember to turn off the bluetooth between syncs. But it tracks my resting heartrate every night, and the website insights and data are rockstar awesome. I love being able to look through my data how I want, and I’m looking forward to when they have an API to play with. Right now you have to get on a waitlist to get the product but I really, truly adore this device. Also, it’s a watch! Yes, it’s not exactly fashionable, but it tells the time and you don’t look like you’re wearing a medical device. The idea behind Basis is very Quantified Self-friendly – it watches your activity and then suggests habits you should try to attain – sometimes it’s going to sleep at a regular time, for some people it suggests getting up once an hour during work time. If you read out the habit suggestions in the right voice you realize that you’re strapping a Jewish mother on your wrist… not that that’s a bad thing!

The thing I love best about this device is something that’s not immediately obvious – although it isn’t great at tracking your heart rate while you’re exercising, it does a fantastic job of tracking your heart rate while you sleep. Anyone who has ever done heart rate training knows that your resting heart rate is one of the best measures of cardiac fitness – both as an indicator of general fitness (average) and a flag to let you know when you’ve overtrained, or you’re fighting sickness (or perhaps partied too hard the night before). Having this data tracked and recorded is incredibly useful, and this feature should be hailed much more widely.

Related Sites

Check out RunKeeper, who has a nice smartphone application for running/walking as well as a fantastic health graph API. If and when I create an awesome workout application, I’ll totally be using the Runkeeper API as my backend.


Bodymedia Fit Fitbit Jawbone Up Withings Pulse Basis
Price $150 + $7/month $69-$99 $69-$99 $99 $199
Heart Rate No No No No Yes
Yes No No No Yes
Sleep Auto Manual (button) Manual (button) Manual Auto
API Excellent Excellent Excellent Minimal None yet
Dashboard App + Website: Excellent App + Website: Excellent App + Website App only App: Minimal Website: Excellent
Charging Dongle/1 hour Dongle/1 hour Dongle/1 hour Dongle/ 1 hour Cradle (weird): 2 hours
Battery Life 3 days 7 days 7 days 7 days 3 days
Sync Tethered or Bluetooth (manual) Automatic when near phone, base – or manual via bluetooth Plug into smartphone (headphone jack) Manual via bluetooth Manual via bluetooth or when charging

Posted in Geek Stuff.

  • TanĂ© Tachyon

    Huh, I’m a clip-on-the-bra-strap Fitbit wearer but have never run it through the wash. Forgotten to take it off the charger and put it back on, sure, but not run it through the wash.