VI. INSTRUCTIONS FOR OPERATION
24
3. Oshima Y & Shiga T. Within-day variability of whole-body and segmental bioelectrical impedance in a standing position,
European Journal of Clinical Nutrition 2006, 60, 938-941
The chart above depicts changes in segmental impedance throughout the day, as reported by Oshima et al.
(NOTE: ZH-H, ZF-F, and ZH-F refer to Hand-to-Hand, Foot-to-Foot, and Hand-to-Foot respectively.)
3
09:00
60
40
20
-20
-40
-60
0
12:00
15:00
18:00
(Ω)
impedance
Z
H-H
Z
F-F
Z
H-F
(3) Do not shower or bathe directly before measurement.
Perspiration can result in a temporary change in body composition measurements, as the
accuracy of BIA depends largely upon interpretation of measured impedance values, which
are affected greatly by hydration levels.
(4) Perform the measurement under normal temperature conditions (24-28°C)
Extreme temperatures (both hot and cold) can result in temporary physiological changes. For
example, excessive sweating due to heat can cause increased impedance measurements,
resulting in a higher fat calculation. For best results, measurements should be conducted in
an environment between 24-28°C.
(5) Remove shoes and socks before measurement.
Shoes and socks will interfere with the electric current, making measurement inaccurate or in
some cases, impossible.
(6) Avoid physical contact with other people during measurement.
Because BIA measures the impedance encountered as the electric current travels through
the subject's body, if another individual is touching the subject, the electric current may pass
through the other individual, causing inaccuracy in measurement results.
(7) Measure height accurately
Inaccurate height input will affect estimation of body composition.
(8) Perform the measurement in the morning.
As a general rule, BIA measurements should be performed in the morning to minimize the
influence of activity throughout the day on measurements.
