dale schoeller

Bedrest shifts fasting and postprandial fuel selection towards carbohydrate use over lipids, potentially affecting astronauts’ performance and health. We investigated whether this change occurs in astronauts after at least 3 months onboard the International Space Station (ISS). We further explored the associations with diet, physical activity (PA), and body composition. Before and during spaceflight, respiratory quotient (RQ), carbohydrate, and fat oxidation were measured by indirect calorimetry before and following a standardized meal in 11 males (age = 45.7 [SD 7.7] years, BMI = 24.3 [2.1] kg m−²). Postprandial substrate use was determined by 0-to-260 min postprandial incremental area under the curve (iAUC) of nutrient oxidation and the difference between maximal postprandial and fasting RQ (ΔRQ). Food quotient (FQ) was calculated from diet logs. Fat (FM) and fat-free mass (FFM) were measured by …

BackgroundThe association of total energy intake (EI) with all-cause mortality is uncertain, as are the dependencies of this association on age and weight change history.ObjectivesTo identify an EI biomarker suitable for use in epidemiologic association studies, and to study EI associations with total mortality in a Women’s Health Initiative (WHI) cohort of postmenopausal U.S. females (1993-present).DesignEI biomarkers were developed based on doubly-labeled water (DLW) total energy expenditure (TEE) and weight variation during the two-week DLW protocol period using the energy balance method, in an embedded feeding study (n=153). This along with two earlier WHI nutrition biomarker studies having TEE assessments (n=1131 total), with 14.6 years (median) follow-up, constituted a prospective cohort for the study of EI and all-cause mortality.ResultsAn empirical biomarker for log (EI) was developed that had …

We aim to understand the effects of hydration changes on athletes’ neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration …

Background & aimsThe multicompartment approach to body composition modeling provides a more precise quantification of body compartments in healthy and clinical populations. We sought to develop and validate a simplified and accessible multicompartment body composition model using 3-dimensional optical (3DO) imaging and bioelectrical impedance analysis (BIA).MethodsSamples of adults and collegiate-aged student-athletes were recruited for model calibration. For the criterion multicompartment model (Wang-5C), participants received measures of scale weight, body volume (BV) via air displacement, total body water (TBW) via deuterium dilution, and bone mineral content (BMC) via dual energy x-ray absorptiometry. The candidate model (3DO-5C) used stepwise linear regression to derive surrogate measures of BV using 3DO, TBW using BIA, and BMC using demographics. Test-retest precision of the …

BackgroundAthletes vary in hydration status due to ongoing training regimes, diet demands, and extreme exertion. With water being one of the largest body composition compartments, its variation can cause misinterpretation of body composition assessments meant to monitor strength and training progress. In this study, we asked what accessible body composition approach could best quantify body composition in athletes with a variety of hydration levels.MethodsThe Da Kine Study recruited collegiate and intramural athletes to undergo a variety of body composition assessments including air-displacement plethysmography (ADP), deuterium-oxide dilution (D2O), dual-energy X-ray absorptiometry (DXA), underwater-weighing (UWW), 3D-optical (3DO) imaging, and bioelectrical impedance (BIA). Each of these methods generated 2- or 3-compartment body composition estimates of fat mass (FM) and fat-free mass …

BackgroundThe association of TEE with all-cause mortality is uncertain, as is the dependence of this association on age.ObjectivesTo examine the association between TEE and all-cause mortality, and its age interaction, in a Women’s Health Initiative (WHI) cohort of postmenopausal United States women (1992–present).MethodsA cohort of 1131 WHI participants having DLW TEE assessment of ∼10.0 y (median) following WHI enrollment with ∼13.7 y (median) of subsequent follow-up, was used to study the EE associations with all-cause mortality. To enhance the comparability of TEE and total EI, key analyses excluded participants having >5% weight change between WHI enrollment and DLW assessment. The influence of participant age on mortality associations was examined, as was the ability of concurrent and earlier weight and height measurements to explain the results.ResultsThere were 308 deaths …

BackgroundDysregulated energy metabolism is one hypothesized mechanism underlying frailty. Resting energy expenditure, as reflected by resting metabolic rate (RMR), makes up the largest component of total energy expenditure. Prior work relating RMR to frailty has largely been done in cross section with mixed results. We investigated whether and how RMR related to 1-year frailty change while adjusting for body composition.MethodsN = 116 urban, predominantly African-American older adults were recruited between 2011 and 2019. One-year frailty phenotype (0–5) was regressed on baseline RMR, frailty phenotype, demographics and body composition (DEXA) in an ordinal logistic regression model. Multimorbidity (Charlson comorbidity scale, polypharmacy) and cognitive function (Montreal Cognitive Assessment) were separately added to the model to assess for change to the RMR-frailty relationship. The …

Stable isotope dilution and tracer kinetics form the basis for the measurement of the doubly labeled water method. Deuterium and oxygen-18 can be used individually as tracers in water to measure total body water and body water turnover, or combined to measure carbon dioxide production. This revolutionary method of indirect calorimetry provides an investigator the opportunity to measure energy metabolism under free-living conditions for the study of energy balance and weight management. After stable isotope administration, specimens, typically urine, are collected over 1–3 weeks and analyzed using isotope ratio mass spectrometry, however, less expensive and easier to use instrumentation is becoming available.