Factors affecting bioelectrical impedance measurements in humans.
In several groups of young healthy subjects the effect of the ingestion of a meal, of drinking normal tea or beef tea, of exercise and of the menstrual cycle on body impedance was assessed. The day-to-day reproducibility of the method was also investigated under standardized conditions. Two to four hours after ingestion of a meal, body impedance had decreased by about 13-17 Ohms in comparison with body impedance in the fasting state. Drinking 200 ml of normal tea did not result in a change of body impedance, but drinking 200 ml beef tea lowered the body impedance significantly by 4 +/- 4 Ohms. Moderate exercise on a bicycle ergometer (90 min, 100 W) did not influence body impedance, but strenuous exercise (90 min, 175 W) resulted in a decrease of 9 +/- 11 Ohms in body impedance. In general, changes in body impedance during the menstrual cycle were small, and only the difference between measurements of body impedance 1 week before the onset of the menstruation and again 1 week after menstruation (8 +/- 9 Ohms) was statistically significant. Under standardized conditions (in the morning, in the fasting state after emptying the bladder) the within-person between-day variation was found to be 2.8 per cent (13 Ohms).
Deurenberg
P
P
Department of Human Nutrition, Agricultural University, Wageningen, The Netherlands.
Weststrate
J A
JA
Paymans
I
I
van der Kooy
K
K
D000273:Adipose Tissue; D000328:Adult; D001823:Body Composition; D001826:Body Fluids / Q000502:physiology; D004326:Drinking; D004435:Eating; D004553:Electric Conductivity; D015444:Exercise; D005260:Female; D006801:Humans; D008597:Menstrual Cycle; D014882:Water-Electrolyte Balance