diary at Telent Netowrks

There are very few Google hits for "Keito K6", so next week this entry#

Fri, 25 Jun 2004 11:25:46 +0000

There are very few Google hits for "Keito K6", so next week this entry will probably join them. There's one of these things in my local supermarket; it measures weight, height and body fat percentage, and calculates body mass index as well.

Up to a point, at least. Accurately calculating body fat mass is a fairly involved process, so instead it just measures the impedance between one hand and the other, which should be in some way related to water content in the body. Muscle holds more water than fat, so based on that and your age and sex (which you tell it), it guesses the fat mass.

Of course, weight also varies a lot during the day with things like hydration, food intake, etc, so should be best done in the morning before doing anything else: let's just say that I have no intention of walking to Tescos in my dressing gown every morning - or even one morning a week - so forget that.

But height? At least it can tell me how tall I am, surely? No, apparently not. My height as measured using a book and a pencil and the dorframe: 170cm. My height as guessed last week by this Health Multifunctional Measuring Unit: 168cm. As guessed last night: 165cm. Now, I've heard of height changes due to spinal compression (see e.g. Measurement of Diurnal Variation in Intervertebral Disc Height in Normal Individuals), but the figure quoted there is less than a centimetre. Besides, my experiment with the book and the doorframe was conducted less than an hour after the second estimate from Keito.

So, not sure what my point is here, but it's probably something along the lines of "don't trust spurious precision".

Oh, and it got the time of day on the printout wrong too ...