How accurate are electrical BF% measuring things?

lizzyvera

Hi,

I had my BF% measured with one of those things you hold in your hands. (I presume they work on the basis that fat and muscle have different resistance?)

Anyway, it said I was 32% fat!
I couldn't beleive it, I'm not very toned but I'm small- about 52kg and 158cm. I would have assumed I was about 20% fat.

Is this an accurate reading? Is it as bad as it seems to me? (I know nothing about fitness.)

Thanks for your time!

davyjose

1) It should ask you to enter height/weight etc.
2) even if it did those aren't very accurate.
3) 32% is high for a man, but it's much more acceptable for a woman. 20% is low enough for a woman (pinch an inch of skin and if you've got any thickness, then your nowhere near 20%)

rubadub

lizzyvera wrote:

Is this an accurate reading?

Those things are brutal, get a calipers, or a mirror.

lizzyvera

Thanks!
The mirror is what I always use. That's the most important thing anyway, feeling okay with it. Weighing scales are also pointless because I would be REALLY fat if I was at the high end of the healthy range.

I should just get a bit fitter and stronger.
Reading all your posts is very inspiring. Being in college can make you completely forget about your health- losing weight for me means I'm clubbing and stressing too much!

cowzerp

These can give accurate results but it is important to use it consistently-idealiy straight after bed before breakfast-if its held wrong it gives wrong figures and if your typing in the wrong results it will also give innacurate readings-get it done by someone who knows how to use them and understands them..been small does not guarantee low body fat!! i would guess that your a vegetarian or not far off it? this would explain your high body fat and low weight, small mass but very small muscle mass-this is always the case with veggies! eat more protein and do weight training..:cool:

t-ha

lizzyvera wrote:

The mirror is what I always use. That's the most important thing anyway, feeling okay with it.

Exactly, no point in getting upset about a physique you liked two minutes ago just because some device threw up a number.

Anyway, yeah fitter & stronger, off you go!

Tar.Aldarion

Use it once a week, at the same time and day, before breakfast. Enter your details and it should be accurate enough.

Dr4gul4

Tar you cant measure BF% if you're just bones and skin

Hulk smash remember

Tar.Aldarion

Man, time to bulk up to save teh rabbit, and my bodyfat.

Hanley

Tar.Aldarion wrote:

Use it once a week, at the same time and day, before breakfast. Enter your details and it should be accurate enough.

The only accurate thing will be the change in what the machine says overtime. It's not giving a "true" bf% reading tho.

nesf

Hanley wrote:

The only accurate thing will be the change in what the machine says overtime. It's not giving a "true" bf% reading tho.

Yeah that's always how I assumed they were useful. But with the amount of factors that can throw it off can it ever give you anything but a very rough idea of what might be happening?

Tar.Aldarion

I thought of them as fairly inaccurate, really just telling you in what range you are in, the factors athat are meant to throw is off are supposed to be accounted for by doiung it the same time before breakfast every week, to allow your body to go through a cyycle of changes...or something.

nesf

Tar.Aldarion wrote:

I thought of them as fairly inaccurate, really just telling you in what range you are in, the factors athat are meant to throw is off are supposed to be accounted for by doiung it the same time before breakfast every week, to allow your body to go through a cyycle of changes...or something.

I'm curious about the formulas and what they take into account. Surely body composition outside of height (just broad vs narrow people as the easy example) would screw with things if you were working off an "average" composition for a height X? Or even long-legged people versus long-bodied etc.

Hanley

nesf wrote:

Yeah that's always how I assumed they were useful. But with the amount of factors that can throw it off can it ever give you anything but a very rough idea of what might be happening?

Yeah I agree, doing it before breakfast MIGHT help tho. I honestly don't know. I DO know that even hydration levels **** up the readings.

My bodyweight fluctuates from 1-2kg over course of a day like, so first thing in hte AM before breakfsat is when i do any of my readings (tape measurement, bodyweight and caliper readings)

nesf

Hanley wrote:

Yeah I agree, doing it before breakfast MIGHT help tho. I honestly don't know. I DO know that even hydration levels **** up the readings.

My bodyweight fluctuates from 1-2kg over course of a day like, so first thing in hte AM before breakfsat is when i do any of my readings (tape measurement, bodyweight and caliper readings)

Oh and the other question, when should you take your height measurement since people shrink over the day? First thing in the morning when they are at their tallest or the middle of the day or whatever?

Tar.Aldarion

How much does height vary? Not enough to matter much?
I know that one of the things taken into account is the hydration levels, that was a major factor in the wait a week thing. I don't know how they take bodies into account, maybe just the average width etc.
It askes for age, height, gender etc, not broadness though.

nesf

Tar.Aldarion wrote:

How much does height vary? Not enough to matter much?

I'm 6'1" in the morning and 6' exactly by night time, so maybe just enough to matter.

Tar.Aldarion wrote:

I know that one of the things taken into account is the hydration levels, that was a major factor in the wait a week thing. I don't know how they take bodies into account, maybe just the average width etc.
It askes for age, height, gender etc, not broadness though.

There are "average frame measurements" that I'd assume they used to simplify for the sake of a single (impedance?) target for bodyfat at a certain height. That or they sampled a bunch of people who were 6 foot, took their impedance reading and their body fat using a calliper or whatever and came up with some relation. I'm just curious from a scientific perspective rather than anything else and I'm curious about how quickly it becomes "inaccurate" and what "average build" it's basing it off of.

Tar.Aldarion

http://en.wikipedia.org/wiki/Body_fat_percentage#Bioelectrical_Impedance_Analysis
Is a good start, resistance baby.

The Height and Circumference Methods might be a bit more accurate

nesf

Tar.Aldarion wrote:

http://en.wikipedia.org/wiki/Body_fat_percentage#Bioelectrical_Impedance_Analysis
Is a good start, resistance baby.

The Height and Circumference Methods might be a bit more accurate

So directly, the biggest factor will be your hydration level. Wouldn't environmental factors like the heat of the previous day or night, your diet the previous day and other stuff really screw with it then?

Tar.Aldarion

I imagine a lot of stuff throws it off, up and down, I don't know much about what formulae they use. As for the diet, you are meant to follow a set diet on it I think. It gives an example with mine. I just won one in a treasure hunt at work and read about it.

cowzerp

Hanley wrote:

Yeah I agree, doing it before breakfast MIGHT help tho. I honestly don't know. I DO know that even hydration levels **** up the readings.

My bodyweight fluctuates from 1-2kg over course of a day like, so first thing in hte AM before breakfsat is when i do any of my readings (tape measurement, bodyweight and caliper readings)

By doing it in the morning you are more likely to be consistent-there is no food to interfere with the reading and your at your proper weight discounting food and wee that you might be carrying through the day!! if used properly they are very good. in my gym clients who do there own always do it wrong so i dont reccomend that-when i do it the readings are very accurate, calipers, not my cup of tea due to human error and people lie to themselves and trainers might lie if your paying 50 yo yos to see him and he wants you to come back for more-you dont see any reading..each to there own
its all only guidelines anyway..