title: Effects of skin blood flow and temperature on bioelectric impedance after exercise.
abstract: To examine the effects of increased skin blood flow (BFsk) and skin temperature (Tsk) on bioelectric impedance (BIA), 30 young males participated as subjects. All subjects underwent the following measurements: 1) BFsk and Tsk for the chest, biceps, thigh, and calf; 2) body composition using the BIA prediction equations and underwater weighting (UW); and 3) triceps skinfold (SFtri) thickness. After the baseline studies (M1) the subjects exercised for 30 min at approximately 83% of maximal heart rate. The above measurements were repeated immediately after exercise (M2), and at 1-h recovery from exercise (M3). Repeated measures ANOVA showed that mean Tsk and BFsk, and for the four measured sites were significantly increased from M1 to M2 (P < 0.05) and decreased from M2 to M3 (P < 0.05). These changes did not affect BIA measurement for resistance (R) and reactance between M1 and M2 (P > 0.05), and between M2 and M3 (P > 0.05). With regression analysis the following independent variables were identified as strong contributing factors for predicting fat-free mass (FFM): 1) SFtri and total body water for M1 and M3; and 2) WT, SFtri, and Tsk of the chest for M2. Two FFM equations have little multicolinearity (M1 and M2), e.g., they have low root mean square errors (< or = 2.6 kg), very high values for R2 (> or = 0.94), and relatively low values for coefficient of variations (< or = 5.65%). Differences (P < 0.05) were observed between the UW method and the Lukasi equation for estimating FFM for M1 and M3, but not for M2.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Human Performance Laboratory, University of Medicine and Dentistry of New Jersey, Stratford 08084.
authors.forename: M T
authors.initials: MT
authors.lastname: Liang
authors.forename: S
authors.initials: S
authors.lastname: Norris
mesh_terms: D000328:Adult; D001823:Body Composition; D017097:Electric Impedance; D015444:Exercise / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*; D012881:Skin Temperature / Q000502:physiology