Friday, March 12, 2021

How devices like InBody (Bioimpedance Analysis) work?

With events like the Transformation Challenge coming to an end in the OTF world I have seen many questions and concerns regarding accurate measurement of body composition. Specifically, the Inbody that OTF uses. Tools that use bioimpedance analysis (BIA) can be very accurate and very inaccurate based on many factors that surround using the device. 

This article will provide a basic understanding of BIA and what will result in the most accurate reading and why. 

First, let’s discuss how bioimpedance works. Such scales work with the help of sensors underneath your feet and in handles that use bioelectrical impedance. When you step on the scale and hold on to the handles, a small electrical current runs up through your leg and across your pelvis, and through your arms and across your torso, measuring the amount of resistance from various body tissue. Fat, blood, skeletal muscle, and bones all have different densities and therefore create different levels of “resistance” that is detected when performing a BIA. The devise then reports these different resistance and fat, muscle, and body water. For example, your muscles contain a high percentage of water, resulting in less resistance. Body fat, on the other hand, contains very little water and presents much higher resistance compared to muscle mass or body water. 



There are several underlying factors that can and will cause an inaccurate reading. Here are a few of the most common

1.     Dehydration: Water is a conductor of electricity, so when our bodies are dehydrated it causes electrical resistance when the device performs the scan.  This resistance is read as “fat” since fat contains less water than muscle. This is why proper hydration is vital to an accurate reading. As a side note, it is safe to presume that most people live in a state of dehydration.

2.     Implants: Implants (breast) also create higher resistance to the BIA scan and will results in a higher body fat percentage. I am not sure if there is a difference between saline fill versus silicone fill? The good news is that your scans should remain consistent. Which means, your initial scan will show that you have higher body fat than you actually have, but when you re-scan after taking part in a resistance/ exercise training program, if your scan now shows a decrease in body fat you have indeed lost fat. So, continue to base your future results/ success off that initial base line scan. Just understand that your body fat reading will still read higher than you actually have.


There are other factors that you should consider as well when scanning.  Clothing, time of day, and possible water retention due to foods consumed or menstrual cycle.  These will have a lessor effect on body composition but may be considered for consistency and the most accurate reading.



How to get the most accurate body composition reading? I recommend that you seek out a DEXA Scan. A DEXA scan is a non-invasive test that measures bone mineral density to assess if a person is at risk of osteoporosis or fracture. DEXA stands for dual energy x-ray absorptiometry—in short, with this procedure two X-ray beams are aimed at the bones. This great devise also happens to measure body composition as well.

When getting this scan for purposes of osteoporosis detection it likely will be covered under most insurance.  However, if you are getting this scan for body composition purposes you will likely need to pay out of pocket without insurance reimbursement.  If you are fortunate to live in or near a college town, you can likely get this scan at a very low cost if not free.  Often times, colleges and universities will use DEXA as part of a research project or for student practice/ experience.  


I have included a few resources below to allow you to dig a little deeper so you can make the best most informed decision on what type of scan you should obtain.


My recommendation:

Under the right conditions, the InBody will give you a very accurate and convenient scan that will allow you to track results over time for the average person


Be well and as always, WIN THE DAY!




"Life Is Motion"

"Life Is Motion"
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