Body Fluid Estimation Via Segmental Multi-Frequency Bioelectrical Impedance Analysis Following Acute Resistance Exercise

Segmental multi-frequency bioelectrical impedance analysis (S-MFBIA) estimates body composition and fluids by passing electrical currents through the body and can separate the body into distinct segments. The minimum required abstention from exercise before S-MFBIA is unclear. PURPOSE: The purpose of this study was to monitor changes in total body water (TBW), intracellular water (ICW), and extracellular water (ECW) estimated via S-MFBIA following acute, localized bouts of resistance exercise (RE). METHODS: Thirty-two female (n = 18; age: 22.7 ± 1.4 y; height: 167.5 ± 7.5 cm; body mass: 66.6 ± 14.5 kg; body fat: 30.3 ± 6.2%) and male (n= 14; age: 24.2 ± 2.9; height: 178.7 ± 5.3; body mass: 85.7 ± 7.8 kg; body fat: 19.6 ± 6.9%) resistance-trained volunteers completed three randomly assigned conditions in a crossover design. Each RE protocol (REUPPER or RELOWER) consisted of three exercises and began with two warm-up sets of 12-15 repetitions per exercise. This was followed by a RE circuit of 5 sets of 10 repetitions per exercise with a one-minute rest interval between circuits. In the resting (REST) condition, participants did not complete any physical activity. S-MFBIA was performed at five timepoints: pre-exercise, immediate post-exercise, 15-, 30-, and 60-minutes post-exercise. Data were analyzed using linear mixed-effects models with a random intercept for participant. In all models, REST was the reference condition, and pre-exercise was the reference time point. RESULTS: Although body mass did not differ between conditions, condition by time interactions were observed for TBW, ICW, and ECW (p\u3c0.001 each), with the higher values observed at post-exercise time points in REUPPER as compared to the REST condition. Mean differences between REUPPER and REST for TBW, ICW, and ECW ranged from 0.6-1.0 kg, 0.4-0.6 kg, and 0.2-0.4 kg, respectively. Conversely, RELOWER did not alter fluid estimates. CONCLUSION: An acute increase in TBW, ICW, and ECW is detected by S-MFBIA after a single bout of upper body, but not lower body, RE. This could be due to the smaller initial diameter and greater relative change in diameter of the arms as compared to legs. Due to the potential of artificial body fluid changes, users should avoid exercise – particularly upper body exercise – prior to S-MFBIA assessments

Acute Resistance Exercise Influences Bioelectrical Impedance Analysis Segmental Fat Mass Estimates

Bioelectrical impedance analysis (BIA) is an attractive tool for routine assessment of human body composition. However, there is also concern regarding how some variables, particularly exercise, may affect its measurements and therefore limit the conditions under which this technology can provide useful body composition data. PURPOSE: The purpose of this study was to determine if acute, localized resistance exercise (RE) compromises the validity of BIA segmental fat mass (FM) estimates. METHODS: In a crossover design, 32 healthy, resistance trained adults (18 F, 14 M; age: 23.4 ± 2.3 y; height: 172.4 ± 8.7 cm; body mass: 74.9 ± 15.3 kg; body fat: 25.6 ± 8.4%) completed three conditions in a randomized order: lower-body resistance exercise (L), upper-body resistance exercise (U), and rest (R). The RE protocol included a warm-up consisting of 2 sets of 12-15 repetitions of 3 upper-body exercises (U), or 3 lower-body exercises (L), followed by 5 sets of 10 repetitions per exercise, with 1-minute rest intervals. The R condition involved no exercise. BIA (InBody 770) was completed immediately pre- and post-exercise and at 15-, 30-, and 60-minutes post-exercise. The effects of the acute RE session on BIA estimates of total and segmental FM were analyzed using linear mixed-effects models with condition and time specified as within-subject factors and a random intercept for participant. In all models, the reference groups were R for condition and the pre-exercise time point for time. RESULTS: Condition by time interactions were observed for total and segmental FM. Examination of model coefficients indicated that most condition by time interactions were attributable to differences in the U condition across time relative to the reference group (i.e., R condition at baseline). In relation to the reference group, mean decreases of 0.75 to 1.25 kg for total FM, 0.38 to 0.58 kg for trunk FM, 0.27 to 0.47 kg for leg FM, and 0.15 to 0.22 kg for arm FM were observed in the U condition (p≤0.001 for all). In contrast, no changes across time were observed in the L condition. CONCLUSION: These findings suggest that an acute bout of localized RE influences BIA total and segmental FM estimates to an extent that can compromise accurate interpretation of the results. These data corroborate the need for a period of rest from physical activity, particularly upper body RE, prior to BIA body composition assessment

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit. © 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). All rights reserved.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]