Percent Body Fat? Hydration index?

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I noticed our Kroger has a new blood pressure machine, that will measure and give a print out of your blood pressure, BMI, weight, body fat composition, and hydration index. How "accurate" do you suppose these are, in comparison to any other little gadgets around? Like the little handheld thing they provide at gyms or so forth? My weight was a few pounds off my weight on my own scale -- but it was late evening, and mine was early morning so even for a sitting weight I think it's probably accurate for weight!

Even if not so accurate, it'd be neat to see my different numbers go up/down depending as I lose weight, by measuring it on the same machine every so often. My body fat composition was a 39 point something which is terrible, but was probably worse 30 pounds ago. And my hydration index was a 2.42. I'm not sure what that means, good/bad/decent? I could only find information on hydration percentages not index. My husbands was a -4.34 .. so I'm assuming that's not good being negative?

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  • mitcheljschapira
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    I found your question because I was looking for the answer to the exact same question, right down to the new machine in the grocery store! Although, here in Alaska the "Kroger's" is called "Fred Meyers." My index was also a negative number, but I have been drinking a LOT of water and so I question whether or not a negative number is so bad. Also, the machine recorded my weight at 70 lbs less than what I know it to be. My point is, once I find out what a hydration index is, I am not too sure that I will have much confidence in the grocery store machine.
  • Lyadeia
    Lyadeia Posts: 4,603 Member
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    I find it hard to believe that a machine in a grocery store free for the public's use is anywhere near accurate at measuring body fat, body composition, etc. Weight and blood pressure, yes, but body fat, no. As far as the hydration index, I don't know anything about it.
  • Jeffbeemee
    Jeffbeemee Posts: 2 Member
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    Check out StayHealthy's site for more info:

    http://www.stayhealthy.com/en_us/main/faqs
    then click on question 5 that asks: How is the StayHealthy Hydration Index measured?

    There is also more info in a PDF file under the same question.
  • Jeffbeemee
    Jeffbeemee Posts: 2 Member
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    Also, the machine recorded my weight at 70 lbs less than what I know it to be. My point is, once I find out what a hydration index is, I am not too sure that I will have much confidence in the grocery store machine.

    When weighing yourself, it's important to know that the seat is the scale. There is a slanted piece of metal connected to the seat where you need to put your feet. Also make sure you don't lean on the arm rest. The first time I weighed myself, I didn't put my feet in the correct place and my weight was off too.
  • subigirl
    subigirl Posts: 53 Member
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    Actually, I had my body fat measured by one of my fellow trainers at the gym the other day, and found one of these machines in my grocery store this weekend.

    The scale was pretty accurate, but you have to be sure to follow the instructions and put your feet on the little bar as the instructions tell you (the first time my husband did it, it said he was in the 160's, but our home scale says he is 190...I told him that couldn't be right, because if our home scale was THAT off, that means I'm under 100 lbs? Not possible with my athletic build). He measured again, and his weight was more right on with our home scale.

    I measured, and found my weight to be fairly accurate, and the body fat measurement was in line with the caliper measurement I got earlier in the week. It seems to use the same technology as the hand-held body fat devices you find some trainers use (I have both the hand held and the calipers, as I find some clients who are just starting out and have a lot of weight to lose are a bit uncomfortable with the calipers).

    Now, for the original question, the information I have found is that normal hydration is a hydration index of about .76. If your hydration index is a negative number, you are definitely dehydrated. If it is over, chances are you are retaining water (mine was 1.36, but it is also THAT time of month, so this makes sense...and I drink about 100 oz a day). It is measuring hydration based on the information it is fed....height, the weight it gets from the scale, and the pulse it sends through you to measure fluid and body fat. My husband's was -.96, which naturally I griped at him at (as well as the other measurements of course), because he became rather ill a couple of months ago due to dehydration...so ill I sent him to the doctor because I couldn't figure out what was wrong. He never likes to drink water...complained it was because the tap water tasted terrible, so I started buying bottled. This measurement proves he still isn't taking care of himself AFTER his doctor griped at him for being dehydrated as well as myself.
  • bassilap
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    http://sinnerchiropractic.com/wp-content/uploads/2012/07/How-to-Measure-Body-Fat.pdf

    This is a scientific article that compared the StayHealthy Body fat calculations to other methods currently used to test bodyfat percentage. In layman's terms: The results found that the body fat calculations were similar suggesting that the StayHealthy machine does a pretty good job of getting the correct body fat percentage.

    If I find something about the hydration status, i'll upload it.
  • crazychild1919
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