Using InBody Testing to Measure the Accuracy of Bioelectrical Impedance When Affected by Different...
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Using InBody Testing to Measure the Accuracy of Bioelectrical Impedance When Affected by Different Hydration Levels Jack Streibich and Lindsay Wendt Mr
Using InBody Testing to Measure the Accuracy of Bioelectrical
Impedance When Affected by Different Hydration Levels Jack
Streibich and Lindsay Wendt Mr. Spangler- Whitefish High School-
Advanced Chemistry
Slide 2
Research Question and Hypothesis Does BIA (Bioelectrical
Impedance) accuracy vary as level of hydration fluctuates? If the
subject is dehydrated then BIA will be less accurate(give a higher
body fat estimate).
Slide 3
What is the In-Body Test? Uses bioelectrical impedance to
measure total body water o Sends electronic pulses through the body
to measure total amount of water inside the body Total body water
can be used to determine BMI, BFP, FAT, and SMM.
Slide 4
Basic Principles of BIA Electrical currents travel faster
through water than other solid materials o Muscles are primarily
made up of water o Fat has a much lower water content Creates body
fat estimate by measuring the time taken for different frequencies
to reach electrodes o The slower the time, the more fat there
is
Slide 5
Slide 6
Possible Inaccuracies with Inbody Hydration Levels o
Overhydration- Decreases bodys electrical resistance because the
extracellular water amount increases, allowing the current to
travel quicker o Dehydration- Increases bodys electrical resistance
because the extracellular water amount decreases, causing the
current to travel slower Consuming food before testing affects
hydration
Slide 7
Procedure 20 Whitefish High School student volunteers o Two
groups of ten Each group went through a cycle of being hydrated and
over hydrated o Being InBody tested during each phase of the cycle
Other factors such as amount of water consumed, whether or not they
ate breakfast, and exercise were also monitored
Slide 8
Procedure Continued Sample of testing procedure
Slide 9
Hydration Standards 100 oz - considered hydrated for girls 125
oz - considered hydrated for boys Anything significantly less was
considered dehydrated
Slide 10
Results Groups: o 1- Overhydrated the first day, normal on
second o 2- Normally hydrated the first day, over on second PBF: o
Percent of Body that is Fat Change in PBF: o PBF Dehydrated- PBF
Normally hydrated Hypothesis: o Change in PBF will be negative
because lower hydration levels should resist impedance.
Tests Conditions: Data is matched(not independent) Individuals
are independent Normal population o Distribution clearly normal
Both unimodal and symmetric
Slide 13
Testing Methods Various Students T tests were used to determine
whether factors such as hydration and eating before testing
affected the consistency of the InBody test.
Slide 14
Test 1 Subjects include those who: o Drank recommended amount
of water Ho: There is no difference between PBF when hydrated and
PBF when dehydrated. Ha: There is a difference between PBF when
hydrated and PBF when dehydrated. t=.367 p=.719 95% int(-.678,.958)
P value of.719 is above a.05 alpha level, so we fail to reject the
null hypothesis. There is no evidence of a difference between PBF
when hydrated and dehydrated
Slide 15
Test 2 Subjects include those who: o Drank recommended amount
of water o Ate breakfast before both tests Ho: There is no
difference between PBF when hydrated and ate breakfast and PBF when
dehydrated and ate breakfast. Ha: There is a difference between PBF
when hydrated and ate breakfast and PBF when dehydrated and ate
breakfast. t=1.55 p=.152 95% int(-.27,1.5) P value of.152 is higher
than.05 alpha level so we failed to reject our null hypothesis.
There is no evidence that eating breakfast affects PBF.
Slide 16
Test 3 Subjects include those who: o Drank recommended amount
of water o Did not eat breakfast before either test Ho: There is no
difference between PBF when hydrated and didnt eat breakfast and
PBF when dehydrated and didnt eat breakfast. Ha: There is a
difference between PBF when hydrated and didnt eat breakfast and
PBF when dehydrated and didnt eat breakfast. t=-2.5 p=.0875
95%int(-2.76,.326) P value of.0875 is higher than.05 alpha level
but not much higher. Still we fail to reject the hypothesis. There
is little evidence that not eating affects PBF.
Slide 17
Conclusion All three tests failed to show evidence of variables
changing PBF levels. It is likely that BIA is relatively
consistent, and may be more accurate than we expected.
Slide 18
Improvements Specific group of individuals must be targeted and
tested both ways with less variables.
Slide 19
References Jansen, Ian, Steven B. Hymsfield, Richard N.
Baumgaurtner, and Robert Ross. "Estimation of Skeletal Muscle Mass
By Bioelectrial Impedance Analysis." Journal of Applied Physiology
89 (2000): 465-71. Web. 5 Oct. 2014. Lukaski, H. C., P. E. Johnson,
W. W. Bolonchuck, and G. I. Lykken. "Assessment of Fat-free Mass
Using Bioelectrial Impedence Measurements of the Human Body." The
American Journal of Clinical Nutrition 41 (1985): 810-17. Web. 19
Nov. 2014. Mackenzie, Brian. "Bioelectrical Impedance Analysis
(BIA)." Bioelectrical Impedance Analysis (BIA). N.p., 10 May 2014.
Web. 11 Jan. 2015.
