Saturday, October 27, 2007

"Body" -> Historical Pulse Levels

Review of the Oregon Scientific Data Logger

Generally, pulse rate monitors are ubiquitous. You can find them very inexpensively, and virtually at any large store. To get an accurate measurement, you normally need a chest strap, which picks up the electrical impulse from your heart. Your pulse rate is then displayed onto a special wristwatch that you wear.

As you get to more sophisticated levels of pulse monitors (higher end Garmin, Polar, and Powertap units), you will also get some ability to store the workout normally onto the wrist watch (or bicycle computer). Monitoring pulse rate during endurance activities is still the simplest measure of activity, although some people are replacing simply pulse monitoring with a more sophisticated power monitoring. However, for the day in and day out athlete, pulse rate is great in helping to get another data point on how hard you are training.

The biggest problem with the normal data logging systems are two fold:

1. They tend to be proprietary
2. They are expensive
3. And due to #2, if you lose or break the pulse monitor, you are stressed (thus leading to weight gain)

Oregon Scientific, gadget maker, has broken through some of this with their data logger. For an inexpensive $30, through Walmart, you can have the ability to record your historic pulse rate for up to 30 hours.

Over the 25 years that I've used pulse monitors, I have a bunch of heart rate straps all over the house. Generally, I've destroyed or lost the watches or cycle computers, before I destroyed the pulse strap. The nice thing about the data logger is that you can use most of you pre-existing straps as long as they are in the 5.3Khz analog range. This means that all your old equipment will probably work.

(Now, the new more sophisticated pulse monitors from Garmin and PowerTap may feature the ANT+ protocol, which is 2.4Ghz, and won't work with this logger, but at this price point, you'll have all the data logging you need with the systems that feature this more sophisticated technology.)

The system is very easy to use:

1. Put on your pulse monitor strap
2. Place the data logger less than 4" from the transmitter
3. Wait for acquisition (solid green LED on the logger)
4. Now you can move is up to 30" away.
5. After the workout, press the button for 2 seconds to turn off
6. Return to PC to upload your work out, which is time stamped

The logger comes with a small app program and a USB cable to download the data. Below is a screen shot of the app.

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The logger program is very unsophisticated, but does the job. I do, however, like the ability to export the data into a CSV file, which you can grab with any spreadsheet program.

For example, below I've posted just sitting at my computer typing. I've then exported the data to Excel, and I've graphed out my resting pulse.

I've set the logger to record every 1 second. As you can see, I've had a couple of movements, which sent my pulse up a bit. However, if you put a trend line on the data (see the equation), the last bit of "47" is where my average pulse is resting just typing. In other words, I have a typing pulse rate of 47 beats per minute. However, you could also do more sophisticated analysis on your heart rate data: RMS, Area Under the Curve, or ramp ability of the heart.

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Some additional features:

There is a finite amount of memory in the system. On the low end, you can record 15 hours at 1 second intervals, but you can set it to record higher intervals. As you would expect, 2 second sampling would give you 30 hours of data logging.

Geek Of The Week Ideas:

1. Obviously, if you can stand the chest strap, it would be interesting to log 24 hours worth of data. How low does your pulse go at night?

2. If you are into weights, interesting to see your pulse during lifts.

3. You can see how your Tabatas went. After all, if Tabatas don't raise your pulse, nothing will.


All in all, for $30, this is a pretty cool little gadget for endurance athletes. If you don't have a pre-existing chest strap, you may want to get an entire ensemble from Walmart with the strap and the watch for an additional $35. However, I cannot vouch for the rest of the system. For me, it would appear that the chest strap is a bit more tricky to get correct. Regardless, Walmart is pretty good about taking things back, so try and return if it doesn't work.

While it is only available on-line, you can always ask them to ship it to the nearest Walmart for free, thus skipping the shipping fees.

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