The effect of the menstrual cycle on bioimpedance reliability
Abstract
The potential influence of the menstrual cycle on percent
body fat (%BF) measurements from bioimpedance analysis (BIA)
was investigated on 36 female Ss (19-40 yr). Subjects were
divided into 2 groups based on oral contraceptive agent
(OCA) use. Those women not using an OCA were placed into
the OFF group (n = 20) and those using an OCA were placed
into the ON group (n = 16). The menstrual cycle was divided
into 4 phases: premenstrual, menstrual, postmenstrual, and
intermenstrual. All subjects were weighed and tested for
%BF using BIA a minimum of 12 times, at least 3 times within
each cycle phase. Subjects were also underwater weighed a
single time, approximately at the middle of their respective
cycles. Repeated measures ANQVAs were used to test for
significance between and within groups for weight,
resistance, and %BF across the 12 measurements and across
the 4 phases. No significance was found for any variable
tested with the exception of weight within each group across
the 12 measurements (p < . 0 5 ) . Percent body fat data from
hydrostatic weighing (HW) were compared to BIA values from
each of the 4 phases using a repeated measures ANOVA and
PPMC. No significant differences were found (p > .05)
between HW and BIA for any phase. The average correlation
between HW and BIA was .78, SEE = 3.3%. Overall, neither
OCA use nor the menstrual cycle itself appeared to influence
%BF measurements from BIA.
Subject
Body composition - Measurement
Oral contraceptive
Menstrual cycle
Impedance - Bioelectric