Bioelectrical Impedance Device Research Articles

The Effects of Short-Term Electromyostimulation Exercises and Different Diet Types on Body Composition in Obese Women

Obesity is one of the world's most risky health problems with increasing prevalence. This study aimed to investigate the effect of calorie-restricted diet and intermittent fasting diet on body composition with electromyostimulation (EMS) applications in obese females. The study was conducted with 90 obese females. Participants were randomly divided into 5 groups, EMS, EMS+intermittent fasting (EMS+IF), EMS+calorie restricted (EMS+CR), intermittent fasting (IF), and calorie restricted (CR) diet groups. EMS groups received 27min/2g/week EMS exercise protocol for 4 weeks. Furthermore, dietary interventions were conducted with all groups (except EMS). Body composition measurements of the participants were obtained with a bioelectrical impedance device. Two-way repeated measures ANOVA was used to analyze the obtained data. BMI, body mass, and body fat weight decreased significantly in the EMS+IF, and EMS+CR groups compared to the EMS group while skeletal muscle weight decreased dramatically in all four groups compared to the EMS group. In body analysis regional (right-left arm, right-left leg, and trunk) parameters, fat weight decreased significantly in EMS+IF, and EMS+CR groups compared to the other groups. Moreover, muscle mass decreased more in the EMS+CR and EMS+IF groups compared to the other groups. Dietary interventions in the form of CR or IF with EMS significantly affected body composition measurements in obese participants. EMS and IF dietary interventions may be therapeutic tools to combat obesity.Keywords:Calorie-Restricted Diet, Electromyostimulation, Exercise, Intermittent Fasting, Obesity

Association between muscle-localized bioelectrical impedance analysis parameters and performance in a multi-set exercise on the isokinetic dynamometer in young women.

This study aimed to verify the relationship between changes in thigh muscle-localized bioelectrical impedance analysis (ML-BIA) parameters and performance in a multiple-set exercise. The sample consisted of 30 female university students (22.1±3.2years). The ML-BIA parameters, including localized muscle resistance (ML-R), reactance (ML-Xc), and phase angle (ML-AngF), were evaluated using a tetrapolar bioelectric impedance device operating at a frequency of 50KHz. The multiple sets protocol was performed with an isokinetic dynamometer. For body composition, total and leg lean soft tissue (LST) were evaluated using dual X-ray absortiometry. Student's t-test for paired samples was used to compare the ML-BIA parameters and thigh circumference pre and postexercise. Linear regression analysis was performed to verify the ∆ML-PhA as a predictor of peak torque for the three sets alone while controlling for total and leg LST. There were differences in the ML-R (∆=0.02±1.45Ω; p=0.001; and E.S=0.19), ML-Xc (∆=2.90±4.12Ω; p=0.043; and E.S=0.36), and thigh circumference (∆=0.82±0.60cm; p<0.001; and E.S=0.16) pre- and post-multiple sets. ΔML-PhA was a predictor of performance in the first set (p=0.002), regardless of total and leg LST. However, the ΔML-PhA lost its explanatory power in the other sets (second and third), and the variables that best explained performance were total and leg LST. The ML-BIA (ML-R and ML-Xc) parameters were sensitive and changed after the multiple sets protocol, and the ΔML-PhA was a predictor of performance in the first set regardless of the total and leg LST.

Validation of Bioelectrical Impedance Devices for the Determination of Body Fat Percentage in Firefighters.

Jagim, AR, Luedke, J, Erickson, JL, Fields, JB, and Jones, MT. Validation of bioelectrical impedance devices for the determination of body fat percentage in firefighters. J Strength Cond Res 38(8): e448-e453, 2024-To cross-validate bioelectrical impedance devices for the determination of body fat percentage (BF%) in firefighters. Twenty-eight structural firefighters were evaluated (female, n = 2; male, n = 26 [mean ± SD] age: 38.2 ± 8.3 years; height: 180.2 ± 7.5 cm; body mass: 86.7 ± 20.8 kg; body mass index: 25.8 ± 7.8 kg·m-2) using multifrequency bioelectrical impedance analysis (MFBIA) hand-to-foot device, and single-frequency BIA foot scale (F2FBIA), and a single-frequency handheld BIA device (HHBIA). Dual X-ray absorptiometry served as the criterion. Validity metrics were examined to establish each method's performance. Body fat % values produced by MFBIA (r = 0.913), F2FBIA (r = 0.695), and HHBIA (r = 0.876) were strongly associated (p < 0.001) with criterion BF% measures. However, MFBIA, F2FBIA, and HHBIA all significantly (p < 0.001) underestimated BF% when compared with the criterion measure. Constant error ranged between 4.0 and 5.5% across all BIA devices. Despite strong associations between the BIA devices included in the current study and the criterion measure, all BIA devices underestimated BF%, which resulted in an overestimation of fat-free mass. In addition, proportional bias was observed in which BF% was overestimated at lower values and underestimated at higher values.

Practical but Inaccurate? A-Mode Ultrasound and Bioelectrical Impedance Underestimate Body Fat Percentage Compared to Dual-Energy X-ray Absorptiometry in Male College Students.

Bioelectrical impedance (BIA) and ultrasound (US) have become popular for estimating body fat percentage (BF%) due to their low cost and clinical convenience. However, the agreement of these devices with the gold-standard method still requires investigation. The aim was to analyze the agreement between a gold-standard %BF assessment method with BIA and US devices. Twenty-three men (aged 30.1 ± 7.7 years, weighing 82.5 ± 14.9 kg, 1.77 ± 0.05 m tall) underwent dual-energy X-ray absorptiometry (DXA), BIA (tetrapolar) and US (three-site method) %BF assessments. Pearson and concordance correlations were analyzed. A T-test was used to compare the means of the methods, and Bland-Altman plots analyzed agreement and proportional bias. Alpha was set at <0.05. The Pearson coefficients of BIA and US with DXA were high (BIA = 0.94; US = 0.89; both p < 0.001). The concordance coefficient was high for BIA (0.80) and moderate for US (0.49). The BF% measured by BIA (24.5 ± 7.5) and US (19.4 ± 7.0) was on average 4.4% and 9.6% lower than DXA (29.0 + 8.5%), respectively (p < 0.001). Lower and upper agreement limits between DXA and BIA were -1.45 and 10.31, while between DXA and US, they were 2.01 and 17.14, respectively. There was a tendency of both BIA (p = 0.09) and US (p = 0.057) to present proportional bias and underestimate BF%. Despite the correlation, the mean differences between the methods were significant, and the agreement limits were very wide. This indicates that BIA and US, as measured in this study, have limited potential to accurately measure %BF compared to DXA, especially in individuals with higher body fat.

Validity of equations for estimating fat-free mass in people living with the human immunodeficiency virus

Background & aimsEquations estimating fat-free mass (FFM) in people living with the human immunodeficiency virus (HIV) show differences in the validation process. The current study aimed to verify the validity of FFM estimation equations derived from bioelectrical impedance (BIA) in people living with HIV aged 40 years and older. MethodsA cross-sectional study was conducted with 68 participants evaluated using dual-energy X-ray absorptiometry (DXA) and by two BIA devices (Analyzer and Biodynamics). The study aimed to determine the validity of six different FFM equations from four different studies by Lukaski and Bolonchuk (1987), Kotler et al. (1996), Beraldo et al. (2015) and Hegelund et al. (2017). Comparisons were made using the t-test or Wilcoxon test. To verify the validity between DXA and two BIA devices, the following statistical analyses were performed: Lin's concordance correlation coefficient, intraclass correlation coefficient, coefficient of determination, standard error of the estimate, differences in the limits of agreement by Bland and Altman analysis, correlation between the average and the differences of the methods by Pearson or Spearman correlation. ResultsOnly equation 2 of Kotler et al. (1996) for males by Biodynamics BIA showed no difference in FFM. The Lin's concordance correlation coefficient was excellent (0.96), irrespective of sex, for Equation 2 of Kotler et al. (1996) by BIA Analyzer. All equations were reproducible (>0.85). The coefficient of determination ranged from 68% to 92%, and the standard error of the estimates ranged from 1.8 kg to 5.0 kg. The differences between the limits of agreement ranged from 7.2 kg to 14.9 kg, and the correlations between the average and the differences of the methods showed differences in FFM for three equations (p<0.01). ConclusionThe choice of equations must consider the equipment used and the sex of the sample investigated. Only Equation 2 of Kotler et al. (1996) was considered valid, irrespective of sex, to estimate the FFM by BIA Analyzer.

Exercise capacity and muscle strength in patients who have undergone the Fontan procedure: a retrospective follow-up study.

Due to their relationship with clinical progression, follow-up of exercise capacity and muscle strength is important for optimal disease management in patients who have undergone the Fontan procedure. We aimed to retrospectively analyze exercise capacity and muscle strength trajectory over approximately 2 years. Exercise capacity was assessed using an exercise stress test with the modified Bruce protocol on a treadmill, hand grip and knee extensor strength using a hand dynamometer, and body composition using a bioelectrical impedance device. Exercise capacity, muscle strength, and body composition follow-up data recorded between 2020 and 2022 were compared. Fifteen patients [median age from 17 (first assessment) to 18 years (last assessment), 5 females)] with a 20-month median follow-up time were analyzed retrospectively. There was an increase in weight, height, body mass index, and body fat weight (p<0.05). There was a tendency for increased handgrip strength (%) (p=0.069), but no significant difference was observed in the knee extensor strength of patients during the follow-up period (p>0.05). The changes in heart rate (HR) and oxygen saturation were higher in the last test than in the first test (p<0.05). Maximum HR (HRmax), % predicted HRmax and HR reserve recorded during the test and HR 1 minute after the test were similar between the first and last tests (p>0.05). After 20 months of follow-up, exercise capacity and muscle strength did not decline; instead, the body mass index and fat weight increased. Patients who have undergone the Fontan procedure may not be experiencing a decline in exercise capacity and muscle strength over relatively short time periods during childhood, adolescence, and early adulthood.

BODY COMPOSITION USING DXA VERSUS BIA IN A MIXED COHORT OF COLLEGE STUDENTS

https://youtu.be/pzOWeEl1S_s BACKGROUND Body composition assessment is an important clinical and research tool. Dual energy x-ray absorptiometry (DXA) is the ‘gold standard’ and useful in the research environment, however, it is expensive, reliant on a trained technician, requires a large space, and is immoveable. Bioelectrical impedance (BIA) measurements have improved with the application of 8-electrode multifrequency units and could offer faster, cheaper, and portable alternative if measurements are comparable. The purpose of this study was to determine how well bone mineral content (BMC), lean body mass (LBM), and fat mass measurements made with BIA compared to those made with DXA. METHODS 46 (36 female) college students [avg 21.2 yr, 167.2 cm, 67.2 kg, 28.9% fat; 6 Asian, 4 Hispanic, 3 Black] had their BIA and DXA whole body composition measured within minutes of each other. Three compartments were compared BIA vs DXA: BMC, fat mass, and LBM. Pearson’s correlation coefficients were determined. RESULTS Absolute fat mass (r=0.95), lean mass (r=0.98), and BMC (r=0.91) were highly correlated between the assessment methods. CONCLUSIONS A quadripolar multifrequency BIA device can be a valid body composition surrogate in research environments using college students when a DXA machine is impractical to use.w

Comparative analysis of body fat measurement using two bioelectric impedance devices and three household scales (with the function of determining body composition) with dual-energy X-ray absorptiometry

Body composition assessment is often used in clinical practice to assess and monitor nutritional status. For example, body fat mass is a predictor of metabolic diseases, and for an athlete it is a criterion of performance. "Gold standard" - the method of dual-energy X-ray absorptiometry - in contrast to bioelectrical impedance analysis, is difficult to apply in everyday clinical practice. Therefore, it becomes relevant to compare the consistency of measured body fat mass using densitometry and bioimpedanceometry. The aim of the study was to perform a comparative analysis of body fat mass estimated by bioimpedanceometry (two bioelectric impedance devices and three household scales with a function of determining body composition) and dual-energy X-ray absorptiometry. Material and methods. Sixteen healthy, physically active adults aged 25 [23; 26] years, male (n=7) and female (n=9), participated in the cross-sectional study. Body composition was assessed under standard conditions in the morning, after a 12-hour fast, using densitometry (Stratos Dr X-ray densitometer) and bioimpedanceometry [bioelectric impedance devices: Medass ABC-01, Diamant AIST (with manufacturer's predictive equations); household scales with a function of determining body composition: Tanita BC-718, Picooc Mini, Scarlett SC-216]. Statistical analysis was performed using Statistica 10 package (StatSoft, USA), and included Friedman's chi-criterion, Lin's correlation concordance coefficient, Bland-Altman method, Spearman's correlation coefficient, and Wilcoxon's criterion with Bonferroni correction for multiple studies. Results. None of the bioimpedanceometry devices studied showed a relationship (Bland- Altman coefficient >0.2) or consistency (Lin's correlation concordance coefficient <0.9) when compared to densitometry, although Spearman correlation was moderate for Tanita BC-718 (r=0.603, p<0.05), Diamant AIST (r=0.641, p<0.01) and Scarlett SC-216 (r=0.609, p<0.05), and notable for Medass ABC-01 (r=0.841, p<0.01) and Picooc Mini (r=0.718, p<0.01). Conclusion. This study found that no bioelectrical impedance device has consistency with dual-energy X-ray absorptiometry in assessing body fat mass. Since the accuracy of body fat mass measurement is critical in body composition diagnosis, the assessment results obtained by bioimpedanceometry should be interpreted with caution.

Weight and Muscle Mass Loss Associated with Acute Disease Can be Reversed with Appropriate Nutrition Therapy and Exercise in a Patient with Amyotrophic Lateral Sclerosisa: A Case Report.

Introduction Nutritional interventions targeting weight loss are useful for the treatment of amyotrophic lateral sclerosis (ALS). However, the changes in body composition after nutritional intervention remain unclear. We herein present a patient with ALS who experienced an increased weight and muscle mass owing to nutritional therapy and physical exercise. Case Presentation An 86-year-old man presented with dysphagia and dysarthria. The patient was diagnosed with bulbar-type ALS. As weight loss progressed, a gastrostomy was performed. After 21 months of disease onset, gastrointestinal bleeding due to a bumper ulcer led to further weight loss (from 40.2 kg to 36.8 kg). The patient experienced difficulty walking and ingesting food orally. Although the total daily energy expenditure (TDEE) was estimated to be 1,122 kcal/day, an intake of 1,500 kcal/day beyond the calculated TDEE was administered. The patient continued to perform daily voluntary exercises in addition to his usual rehabilitation. After 5 months, his weight increased from 36.8 kg to 40.4 kg. Muscle mass increased from 25.1 kg to 30.1 kg, as measured using a multifrequency bioelectrical impedance device. Muscle strength improved from 8.5/10.0 kg to 15.0/18.0 kg in grip strength and from 15.2 kPa to 20.4 kPa in tongue pressure. The patient's physical and swallowing functions also improved. Conclusion In patients with ALS, a decreased body weight and muscle mass due to acute disease may be improved by appropriate nutritional therapy and physical exercise.

Limb-specific isometric and isokinetic strength in adults: The potential role of regional bioelectrical impedance analysis-derived phase angle

Background & AimsIt is not yet known whether regional bioelectrical impedance (BIA) phase angle (PhA) may be informative of different types of strength performed by the lower and upper limbs, independently of lean soft tissue mass (LSTM). Using a sample of healthy adults, we aimed to examine the association and relevance of regional PhA relative to isometric and isokinetic strength of each limb. MethodsA total of 57 participants (32.7±12.9 years; 24.7±3.5 kg/m2) were included in the present investigation. Regional raw BIA variables were determined using a phase-sensitive BIA device. Dual-energy X-ray absorptiometry was used to evaluate LSTM. Absolute isometric and isokinetic (i.e., 60º/s and 180º/s) strength of each limb (extension and flexion) was assessed using an isokinetic dynamometer and used to calculate relative strength. ResultsIn absolute strength, only dominant leg PhA was associated with isometric extension strength (β=0.283) and isokinetic 180º/s flexion strength (β=0.354), regardless of LSTM (p<0.05). In relative strength, a significant association of regional PhA was found for dominant arm flexion isometric strength (β=0.336), and non-dominant arm and dominant leg extension isometric strength (β=0.377, β=0.565, respectively; p<0.05), independently of LSTM. Similarly, for isokinetic 180º/s strength, regional PhA significantly explained the variance in the relative strength of both arms and dominant leg (β=0.350 to 0.506), regardless of LSTM (p<0.05). Relative isokinetic 60º/s strength was not consistently associated with regional PhA (p≥0.05). ConclusionsRegional PhA significantly explained relative (isometric and 180º/s isokinetic strength of both arms and dominant leg), but not absolute muscle strength, independently of regional LSTM. Thus, after accounting for body size, regional PhA seems to have its own characteristics that explain relative strength independently of LSTM.

Visceral fat area measured by electrical bioimpedance as an aggravating factor of COVID-19: a study on body composition

IntroductionSevere forms of COVID-19 are more common in patients with abnormal fat distribution, particularly high visceral adiposity. The patient’s muscle strength may be reduced during the acute phase of the infection. Electrical bioimpedance (BIA) is a non-invasive method for measuring body compartments and estimating visceral fat area (VFA) that can be used at the bedside.ObjectiveTo assess the association between several body composition parameters, primarily high adipose tissue and high VFA, in patients with and without a diagnosis of COVID-19 infection, and whether it worsened the severity parameters.MethodsThis retrospective cohort study was conducted in a private hospital in the city of São Paulo from March 2020 to August 2021. The demographic and clinical data was collected from medical reports. Body composition is assessed using the InBODY® model S10 bioelectrical impedance device and a Jamar® digital hydraulic manual dynamometer with a scale from 0 to 90 kg is used to measure handgrip strength (HGS).ResultsA total of 96 patients with a mean age of 69.1 years (SD 15) were divided into two groups of 48 individuals, with and without COVID-19 infection. Body mass index (odds ratio [OR]: 4.47, 95% confidence interval [CI]: 1.69, 11.83), fat mass (OR: 2.03, 95% CI: 0.48, 8.55), and VFA (OR: 1.08, 95% CI: 0.33, 3.53) were all higher in the infection group. When COVID-19 patients were evaluated, those with higher VFA had longer hospital stays (OR: 0.99, 95% CI: 0.97, 1.01) and used more vasoactive drugs (p = 0.043). Patients with COVID-19 with poor handgrip strength were 3.29 times more likely to require a prolonged intensive care unit (ICU) stay.ConclusionThe study concluded that excess weight and body fat are significantly associated with COVID-19 involvement, but the severity is primarily related to a greater area of visceral fat. The use of bioimpedance for visceral fat measurement was effective, as it is a simple method performed in the hospital setting that does not require the use of radiation.

Bioelectrical impedance devices in clinical practice: a narrative review

Bioelectrical impedance devices in clinical practice: a narrative review

Research on dynamic comfort maintenance by measuring lower limb edema and seat pressure during simulated seated sleep in flight

Objectives. Seated sleep during flight can bring significant discomfort to passengers. The objective of this research was to study passengers’ dynamic comfort maintenance strategies in lower limb postural shifting during seated sleep in flight. Methods. Studies on seated sleep postures and sitting comfort were conducted. First, 40 participants were recruited to the observational research for collecting typical leg postures during seated sleep. Then, an experiment was conducted with the participants simulating seated sleep in the aircraft seat. The changes in lower limb edema and seat pressure in different postures were measured with a bioelectrical impedance device, near-infrared spectroscopy device and pressure mapping device. Results. Six postures were selected through the observational research. The experiment showed that tissues of the thighs and buttocks suffer alternate higher compression by shifting between the six postures. Lower limb edema is higher when the shanks are forward, while the tissue under the ischial tuberosity suffers higher compression when the shanks are neutral. Conclusion. Six motivations for passengers to shift each sitting posture to achieve dynamic comfort were summarized, which helps obtain alternating rest in different body parts. The suggestion of a leg position adjustment system was also proposed.

Comparisons of Two Bioelectrical Impedance Devices and Manual versus Sensor-Based Short Physical Performance Batteries for Assessment of Muscle Mass and Physical Performance.

The assessment of muscle mass and physical performance is essential for the diagnosis of sarcopenia. This study examined the validity of bioimpedance analysis (BIA) and a sensor-based short physical performance battery (SPPB) device for analyzing appendicular skeletal muscle mass (ASM) and physical performance. Forty-one older adults were measured for ASM and physical performance with two BIA devices (InBody770 vs. T-SCAN PLUS III) and two SPPB devices (manual mSPPB vs. sensor-based sSPPB). Validity statistics included the intraclass correlation coefficient (ICC) and Bland-Altman plots to examine the agreement of data from the BIA (InBody770 vs. T-SCAN PLUS III) and the SPPBs (mSPPB vs. sSPPB). There was a significant ICC for skeletal muscle mass between the T-SCAN PLUS III and InBody770 devices (ICC = 0.8822; p < 0.0001). The mSPPB and sSPPB values showed agreement across all components: 0.8654 for the total scores, 0.8879 for the walking speed, 0.8889 for the chair stand, and 0.6863 for the standing balance. No systemic bias was observed between the two methods for the BIA and SPPB devices. Measurements using the T-SCAN PLUS III and sSPPB seem to be highly correlated with the InBody770 and mSPPB devices in older adults and may be valid for assessing muscle mass and physical performance.

#2674 ASSOCIATION BETWEEN SARCOPENIA, BODY COMPOSITION AND FRAILTY IN PERITONEAL DIALYSIS PATIENTS: A MULTI-CENTRIC STUDY

Abstract Background and Aims Patients with chronic kidney disease (CKD) have an increased risk of mortality due to many causes. One of them is sarcopenia, a progressive skeletal muscle disorder that increases adverse outcomes such as fractures, falls, and physical disability, and has been considered an independent risk factor for mortality. Sarcopenia could be defined as a muscle failure in which muscle strength is the most solid measure of muscle function and a better predictor of adverse events rather than muscle mass. Grip strength is considered a reliable surrogate for measures of arm and leg strength. The aim of this study was to evaluate the prevalence of probable sarcopenia in peritoneal dialysis (PD) patients and its association with body composition and several clinical variables. Method This retrospective multi-centric descriptive study was conducted at the Hospital de Santa Cruz (Lisboa) and Hospital Universitario de Badajoz (Badajoz). We performed a single evaluation of 62 patients on peritoneal dialysis from at least 3 months, aged &amp;gt;18 years in whom we measured muscle strength by handgrip strength using a dynamometer. We divided patients into two groups, using cut-off points to consider probable sarcopenia for men and women less than 27 kg and 16 kg, respectively. Patients with acute infection, amputated limbs, and implantable cardiac devices were excluded. The following data were analyzed: age, anthropometric variables, gender, duration, modality of PD, presence of hypertension, diabetes, and cardiovascular disease, obtained from electronic medical records. We also analyze data from body composition using a bioelectrical impedance device (overhydration, extracellular intracellular water ratio (E/I), lean and fat tissue index and phase angle), PD parameters (weekly urea Kt/v, nGFR, D/P Cr, nPCR, residual urine output) and measured serum concentrations of hemoglobin, PCR, NT-ProBNP, PTH, Ca-125, calcium, and phosphorus. We assessed patients for the Clinical Fragility Scale (CFS) and measured performance in activities of daily living using the Barthel Scale. Results Records of 62 patients, 61% male, mean age 57 ± 22 years, and body mass index 27.5 ± 5.1 kg/m2 were reviewed, with 15 (18.8%) classified as probable sarcopenic. Old age (p = 0.005), high CFS score (p = 0.005), E/I ratio (p &amp;lt; 0,001), and low values of lean tissue index (p &amp;lt; 0.031), mean phase angle (p &amp;lt; 0.001) and residual urine output (p &amp;lt; 0,018) were correlated with the presence of probable sarcopenia. In the multivariable analysis, age (HR 1.135; CI 95% 1.015 - 1.269), CFS score (HR 2.637; CI 1,008 - 6,900), and urine output (HR 0,996; CI 95% 0.993 - 0.999) were also related to probable sarcopenia. There was no association between the presence of anemia, cardiovascular disease, type of peritoneal transport, and clearance of small solutes. Conclusion This study reported a low prevalence of probable sarcopenia in PD patients. We corroborate the association between age and frailty in the sarcopenic group. The percentage of extracellular water, muscle mass, and phase angle measured by bioimpedance could be useful variables to identify sarcopenic or at-risk patients. In multivariate analysis, age, higher CFS score, and urine output have been associated with sarcopenia. Preservation of residual renal function seems to be associated with less sarcopenia, which reinforces the importance of preserving residual renal function in PD patients. It's also important to identify sarcopenic or at-risk patients in order to promote early detection and treatment.

Association of 24-h movement behaviors with phase angle in community-dwelling older adults: a compositional data analysis.

Phase angle (PhA) is an indicator of cellular conditions. Recent studies have suggested that PhA supports healthy aging. Identifying modifiable lifestyle factors for PhA is important. The associations of PhA in 24-h movement behaviors, including physical activity (PA), sedentary behavior (SB), and sleep, have not been studied in older adults. We investigated the cross-sectional associations between 24-h movement behaviors and PhA in community-dwelling older adults while appropriately considering the co-dependent nature of daily time use using compositional data analysis. The participants were 113 healthy older adults. PhA was measured using a bioelectrical impedance device. Time spent in light-intensity PA (LPA), moderate- to vigorous-intensity PA (MVPA), and SB was measured using a tri-axial accelerometer. Sleep duration information was self-reported in a questionnaire. Compositional multiple linear regression and compositional isotemporal substitution were performed to examine the associations of 24-h movement behaviors with PhA and hypothetical time reallocation in movement behaviors with PhA, respectively. Even after adjusting for potential confounders, relative to other behaviors more time spent in MVPA was significantly associated with higher PhA (p < 0.001). The 30min/day of time reallocation from the other behaviors (SB, LPA, and sleep) to MVPA was predicted to be 0.12 higher PhA (corresponding to 2.3% increase; 95% CI 0.01, 0.24). Our results suggest that increasing or maintaining the daily time spent in MVPA is important for managing PhA in older adults, regardless of the other behaviors time consumed instead.

Comparison of Hemodynamic and Cerebral Oxygenation Responses during Exercise between Normal-Weight and Overweight Men.

Obesity has negative impacts on cardiovascular function and may increase cerebrovascular complications during exercise. We compared hemodynamic and cerebral oxygen changes during high-intensity exercise between overweight (OW) and normal-weight (NW) individuals. Eighteen NW and fourteen OW male individuals performed high-intensity (70% of peak oxygen uptake, VO2peak) cycling exercises for 30 min. Hemodynamics were measured using a bioelectrical impedance device, and cerebral oxygenation status was measured using a near-infrared spectrophotometer during and after exercise. The VO2peak of NW individuals was significantly higher than that of OW individuals (41.3 ± 5.7 vs. 30.0 ± 5.0 mL/min/kg, respectively; p < 0.05). During the 30 min exercise, both groups exhibited an increase in oxygenated hemoglobin (O2Hb) (p < 0.001), deoxygenated hemoglobin (p < 0.001), and cardiac output with increasing time. Post-exercise, cardiac output and systemic vascular resistance were significantly higher in the OW group than in the NW group (p < 0.05). The O2Hb in the NW group was significantly higher at post-exercise times of 20 min (13.9 ± 7.0 μmol/L) and 30 min (12.3 ± 8.7 μmol/L) than that in the OW group (1.0 ± 13.1 μmol/L and 0.6 ± 10.0 μmol/L, respectively; p = 0.024 vs. 0.023, respectively). OW participants demonstrated lower cerebral oxygenation and higher vascular resistance in the post-exercise phase than non-OW subjects. These physiological responses should be considered while engaging OW and obese individuals in vigorous exercise.

The association between muscle-to-fat ratio and cardiometabolic risks: The China National Health Survey

BackgroundThe relationship between muscle mass and fat mass might be an indicator to assess the cardiometabolic risk independently from overweight/obesity, but evidence from a representative general Chinese population is lacking. ObjectiveTo understand the age- and sex-specific associations between muscle-to-fat ratio (MFR) and cardiometabolic risks in Chinese population. Methods31,178 (12,526 men and 18,652 women) subjects from the China National Health Survey were included. Muscle mass and fat mass were assessed by a bioelectrical impedance device. MFR was calculated as muscle mass divided by fat mass. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), serum lipids, fasting plasma glucose and serum uric acid were measured. General linear regressions, quantile regressions and restricted cubic-spline (RCS) regressions were applied to assess the effect of MFR on cardiometabolic profiles. ResultsPer unit increase of MFR was associated with a 0.631 (0.759–0.502) mmHg SBP decrease in men, 2.648 (3.073–2.223) in women; 0.480 (0.568–0.392) mmHg DBP decrease in men, 2.049 (2.325–1.774) in women; a 0.054 (0.062–0.046) mmol/L total cholesterol decrease in men, 0.147 (0.172–0.122) in women; 0.084 (0.098–0.070) mmol/L triglycerides decrease in men, 0.225 (0.256–0.194) in women; a 0.045 (0.054–0.037) mmol/L low-density lipoprotein decrease in men, 0.183 (0.209–0.157) in women; a 2.870 (2.235–3.506) μmol/L serum uric acid decrease in men, 13.352 (14.967–11.737) in women; and a 0.027 (0.020–0.033) mmol/L high-density lipoprotein increase in men, 0.112 (0.098–0.126) mmol/L in women. The effect in overweight/obese people was much significant than in under/normal weight counterparts. The RCS curves revealed both linear and non-linear relationships between increased MFR and lower cardiometabolic risk. ConclusionsMuscle-to-fat ratio is independently associated with multiple cardiometabolic parameters among Chinese adults. Higher MFR is related with better cardiometabolic health, and the effect is much significant in overweight/obese people and women.

Assessment of exercise capacity using field walking tests in patients after the Fontan procedure: A case–control study

BackgroundDespite the frequent use of the 6-minute walk test (6MWT), exercise capacity has not been assessed with the incremental shuttle walk test (ISWT) in patients who have undergone the Fontan procedure. It is unclear whether these tests cause clinically relevant cardiorespiratory responses in these patients. ObjectivesWe aimed to assess cardiorespiratory responses to the 6MWT and ISWT in Fontan patients, compare the responses with those in the controls, and examine the agreement between the two field tests. MethodsSubmaximal exercise capacity was assessed using the 6MWT, maximal exercise capacity using the ISWT, quadriceps isometric muscle strength with a hand dynamometer, and body composition using a bioelectrical impedance device. ResultsTwenty-one Fontan patients (16.42±6.63 years, 5F/16M) and 21 controls (16.57±4.30 years, 7F/14M) were included. While body composition was similar between the groups (p>0.05), quadriceps isometric muscle strength and 6MWT and ISWT distance were lower in the Fontan patients than in the controls (p<0.05). In both the 6MWT and ISWT, pre- and post-test heart rate (HR), oxygen saturation (SpO2), dyspnea, and leg fatigue differed significantly between the Fontan patients and the controls (p<0.05). In addition, the ISWT resulted in a more significant change in HR, SpO2, and leg fatigue than the 6MWT in the Fontan patients (p<0.05). Bland–Altman plots for the 6MWT vs. the ISWT indicated agreement between the two tests. ConclusionThere were remarkable changes in HR, SpO2, dyspnea, and leg fatigue in both tests. With similar safety to the 6MWT but with more caution applied for adverse events, the ISWT can also be performed as a field test to evaluate exercise capacity and identify more pronounced exercise-induced responses (especially oxygen desaturation) in Fontan patients.

Validity of total body water measured by multi-frequency bioelectrical impedance devices in a multi-ethnic sample

Total body water (TBW) is the largest component of fat free mass and therefore is commonly used in multi-compartment body composition models and as a stand-alone method to assess body composition. Previous literature has not validated bioelectrical impedance spectroscopy device estimates of TBW in racial and ethnic minority populations; previous studies have focused on bioelectrical impedance analysis devices that rely on proprietary algorithms and participant characteristics for accuracy. The purpose of this study was to assess the validity of two bioelectrical impedance spectroscopy devices for measures of TBW compared to a deuterium dilution criterion in a multi-ethnic sample. 109 individuals (55% female, Age: 26.6±6.9yrs, BMI: 25.3±4.0kg/m2) identifying as Asian, African American/Black, Caucasian/White, Hispanic, and Multi-racial were enrolled. After a 12h fast, participants provided a saliva sample for the criterion baseline TBW measure and completed two bioelectrical impedance device (BIS, IB) measurements of TBW. Participants then ingested deuterium oxide (D2O). After an equilibration period, participants provided a second saliva sample for analysis of TBW. For the total multi-ethnic sample, BIS estimates demonstrated good to fairly good agreement (Total error [TE]=2.56L, R2=0.951) and IB estimates were excellent to very good (TE=1.95L, R2=0.975). Validity results did not vary meaningfully between race and ethnicity. The results suggest the BIS and IB devices evaluated can produce valid TBW estimates compared to D2O in a multi-ethnic sample. TBW estimates from the IB may have better agreement with D2O compared to the BIS when using the default settings.