Archive for September, 2016

Wednesday, September 28th, 2016

Quantified bronchitis

Lots of people are using Fitbit to get into better shape. But I haven’t heard of anyone using trackers to better measure what happens when you get sick.

As it turns out, I’ve had a nasty case of bronchitis over the last week. This is the sickest I’ve been in a while, and I find it fascinating to look at the data. I hope folks from Fitbit corporate, and other interested individuals will be able to make use of the data.

First off, here’s what shortness of breath and fever do to you: they raise your heart rate.

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My normal resting heart rate is in the low 60s. But as you can see here, it hardly dropped below 90, even while I was asleep. Fitbit considers a rate of 89 or above to be the “fat burn” zone, and I had an incredible 20 hours less two minutes in that zone. Interestingly, Fitbit considered my resting heart rate to be only 76 bpm. I think it uses some kind of rolling average over many days.

 

Here’s what the resting heart rate looked like:

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And here’s the overall time in various zones.

 

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The highest spike is the day we were just talking about. But days leading up to that had significantly raised heart rate too. After that, it dropped off fast, but the scale can be deceptive. That data point 3rd from the end is still more than four hours in the “fat burn” zone, which is a lot for lying in bed.

Next up, step counts:

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I muddled through Wednesday not feeling well, but activity crashed the way you’d expect, spending entire days in bed.

Lastly calories:

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The leftmost column is the Wednesday I muddled through, with a burn of 3004 calories, which is pretty typical. But the next day, despite my step count dropping by 90%, Fitbit recorded a burn of almost 3,500 calories. True, this was with 14-and-a-half hours in the “fat burn” zone, but I don’t think it could make that much of a difference. This has to be a bug. Someone, my set of physiological conditions triggered some defect in the algorithms that made it badly overestimate my burn.

[From what research I could find, running a fever of 102 indeed increases your basal metabolic rate. But not that much. It probably less-than-compensates for the decreased physical activity while sick.]

Friday, the day I had 20 hours in the “fat burn” zone, I recorded a more realistic 2438 calorie burn.

What do you think? If you have fitness tracker data from when you’re sick, I’d love to see it.

Thanks, -m