The three-compartment (3-C) model of physique assessment (fat mass, fat-free mass, water) incorporates total body water (TBW) whereas the two-compartment model (2-C) assumes a TBW of 73.72%. Deuterium dilution (D2O) is the reference method for measuring TBW but is expensive and time consuming. Multifrequency bioelectrical impedance spectroscopy (BIS SFB7) estimates TBW instantaneously and claims high precision. Our aim was to compare SFB7 with D2O for estimating TBW in resistance trained males (BMI >25kg/m2). We included TBWBIS estimates in a 3-C model and contrasted this and the 2-C model against the reference 3-C model using TBWD2O. TBW of 29 males (32.4 ± 8.5 years; 183.4 ± 7.2 cm; 92.5 ± 9.9 kg; 27.5 ± 2.6 kg/m2) was measured using SFB7 and D2O. Body density was measured by BODPOD, with body composition calculated using the Siri equation. TBWBIS values were consistent with TBWD2O (SEE = 2.65L; TE = 2.6L) as were %BF values from the 3-C model (BODPOD + TBWBIS) with the 3-C reference model (SEE = 2.20%; TE = 2.20%). For subjects with TBW more than 1% from the assumed 73.72% (n = 16), %BF from the 2-C model differed significantly from the reference 3-C model (Slope 0.6888; Intercept 5.093). The BIS SFB7 measured TBW accurately compared with D2O. The 2C model with an assumed TBW of 73.72% introduces error in the estimation of body composition. We recommend TBW should be measured, either via the traditional D2O method or when resources are limited, with BIS, so that body composition estimates are enhanced. The BIS can be accurately used in 3C equations to better predict TBW and BF% in resistance trained males compared with a 2C model.
Ava Kerr, Gary Slater, Nuala Byrne, and Janet Chaseling
Mollie G. DeLozier, Bernard Gutin, Jack Wang, Charles E. Basch, Isobel Contento, Steven Shea, Matilde Irigoyen Patricia Zybert, Jill Rips, and Richard Pierson
Anthropometric and bioimpedance regression equations were developed for young children using total body water (TBW) as the criterion. Ninety-six boys and girls, 4-8 years of age, served as subjects. Measures included height, weight, five skinfold thicknesses, three circumferences, total body bioimpedance, and separate bioimpedance measures of the arm, trunk, and leg. Height and weight alone accounted for .70 of the variance in TBW. Adding other measures did not significantly increase the R 2. Standard errors of estimate for TBW were similar to those reported for older individuals (1.39-1.44 1) but may be too large relative to the small size of the subjects for the equations to be acceptable.
Francesco Campa, Catarina N. Matias, Elisabetta Marini, Steven B. Heymsfield, Stefania Toselli, Luís B. Sardinha, and Analiza M. Silva
standardized for the subject’s stature to classify differences in total body water (TBW; negatively related to vector length) and cell mass (positively related to PA). Even if the accuracy of classic BIVA in assessing the percentage of fat mass (%FM) and hydration status (ie, detection of hyper- or hypo
Beatriz Rael, Nuria Romero-Parra, Víctor M. Alfaro-Magallanes, Laura Barba-Moreno, Rocío Cupeiro, Xanne Janse de Jonge, Ana B. Peinado, and on Behalf of the IronFEMME Study Group
], FM, FFM, and total body water [TBW]) in well-trained females. Material and Methods Subjects A total of 52 eumenorrheic females (age 31.10 [6.25] y; height 163.68 [6.25] cm; weight 58.55 [6.94] kg) and 33 monophasic OC users (age 25.67 [6.33] y; height 162.97 [6.06] cm; weight 57.31 [5.81] kg
Francesco Campa, Matteo Levi Micheli, Matilde Pompignoli, Roberto Cannataro, Massimo Gulisano, Stefania Toselli, Gianpiero Greco, and Giuseppe Coratella
software (G*Power, version 126.96.36.199; Heinrich Heine University, Stuttgart, Germany). We choose the total body water as reference parameter. However, no previous study has investigated it in a similar population. Therefore, given the study design, a medium effect size (ES; f = 0.25), an α level = .05
Alex S. Ribeiro, Ademar Avelar, Witalo Kassiano, João Pedro Nunes, Brad J. Schoenfeld, Andreo F. Aguiar, Michele C.C. Trindade, Analiza M. Silva, Luís B. Sardinha, and Edilson S. Cyrino
synthesis and, thus, contribute to muscle mass accretion ( Farshidfar et al., 2017 ; Schoenfeld, 2010 ). The simultaneous analysis of changes in total body water (TBW) and its extracellular water (ECW) and ICW components may help explain the changes that occur in skeletal muscle mass (SMM) in response to
John R. Stofan, Kris L. Osterberg, Craig A. Horswill, Magie Lacambra, E. Randy Eichner, Scott A. Anderson, and Robert Murray
The authors measured 24-h fluid-turnover (FTO) rate during 6 d of preseason training in U.S. college football players. Players, training (T, n = 9, full gear and contact drills) and reference (R, n = 4, conditioning without gear or contact), ingested a deuterium oxide (D2O) dose and provided urine samples every 24 h for analysis of D2O. During one ~2.3–h practice (wet-bulb globe temperature 24.6 °C), body-mass change, urine production, and voluntary fluid intake were measured to calculate gross sweat loss (GSL). Average FTO was 10.3 ± 2.2 L/d for T and 7.0 ± 1.0 L/d for R. GSL was 3.4 ± 1.5 L for T and 1.7 ± 1.3 for R (P > 0.05). By Day 6, body mass decreased significantly in T (–2.4 ± 1.3 kg, P < 0.05) but not in R (0.38 ± 0.95 kg). With preseason training under moderate environmental stress, football players had high FTO and sweat rates, which might have contributed to a loss of body mass during preseason football training.
Lawrence E. Armstrong
Recreational enthusiasts and athletes often are advised to abstain from consuming caffeinated beverages (CB). The dual purposes of this review are to (a) critique controlled investigations regarding the effects of caffeine on dehydration and exercise performance, and (b) ascertain whether abstaining from CB is scientifically and physiologically justifiable. The literature indicates that caffeine consumption stimulates a mild diuresis similar to water, but there is no evidence of a fluid-electrolyte imbalance that is detrimental to exercise performance or health. Investigations comparing caffeine (100-680 mg) to water or placebo seldom found a statistical difference in urine volume. In the 10 studies reviewed, consumption of a CB resulted in 0-84% retention of the initial volume ingested, whereas consumption of water resulted in 0-81% retention. Further, tolerance to caffeine reduces the likelihood that a detrimental fluid-electrolyte imbalance will occur. The scientific literature suggests that athletes and recreational enthusiasts will not incur detrimental fluid-electrolyte imbalances if they consume CB in moderation and eat a typical U.S. diet. Sedentary members of the general public should be at less risk than athletes because their fluid losses via sweating are smaller.
Francesco Campa and Stefania Toselli
median line of the body and the upper limbs, distant 30° from the trunk. After cleansing the skin with alcohol, the operator placed 2 electrodes (Biatrodes Akern, Florence, Italy) on the back of the participant’s right hand and 2 electrodes on the neck of the right foot. 2 , 7 Total body water (TBW
Alex S. Ribeiro, Matheus A. Nascimento, Brad J. Schoenfeld, João Pedro Nunes, Andreo F. Aguiar, Edilaine F. Cavalcante, Analiza M. Silva, Luís B. Sardinha, Steven J. Fleck, and Edilson S. Cyrino
the square of height (m). Bioelectrical Impedance and Body Composition Measurements Spectral bioelectrical impedance equipment (Xitron Hydra, model 4200; Xitron Technologies, San Diego, CA) was used to estimate total body water (TBW), intracellular water (ICW), extracellular water, resistance ( R