Carbohydrate supplementation maintains physical performance during short-term energy deficit despite reductions in exogenous glucose oxidation.

Exogenous glucose oxidation is reduced 55% during aerobic exercise after three days of complete starvation. Whether energy deficits more commonly experienced by athletes and military personnel similarly affect exogenous glucose oxidation and what impact this has on physical performance remains undetermined. This randomized, longitudinal parallel study aimed to assess the effects of varying magnitudes of energy deficit (DEF) on exogenous glucoseoxidation and physical performance compared to energy balance (BAL).

Low Carbohydrate Availability Promotes a Distinct Circulating microRNA Profile 24 Hours Following Aerobic Exercise.

Low carbohydrate availability during recovery from aerobic exercise alters skeletal muscle microRNA (miRNA) profiles, which may mechanistically regulate exercise recovery. However, its impact on circulating miRNA (c-miRNA) profiles remains unclear. This study aimed to determine the effects of low versus adequate carbohydrate availability on c-miRNA profiles during recovery from aerobic exercise.

Strenuous training combined with erythropoietin induces red cell volume expansion-mediated hypervolemia and alters systemic and skeletal muscle iron homeostasis.

Strenuous physical training increases total blood volume (BV) through expansion of plasma volume (PV) and red cell volume (RCV). In contrast, exogenous erythropoietin (EPO) treatment increases RCV but decreases PV, rendering BV stable or slightly decreased. This study aimed to determine the combined effects of strenuous training and EPO treatment on BV and markers of systemic and muscle iron homeostasis.

Consuming Whey Protein with Added Essential Amino Acids, Not Carbohydrate, Maintains Postexercise Anabolism While Underfed.

Purpose: Energy deficiency decreases muscle protein synthesis (MPS), possibly due to greater whole-body essential amino acid (EAA) requirements and reliance on energy stores. Whether energy deficit-induced anabolic resistance is overcome with non-nitrogenous supplemental energy or if increased energy as EAA is needed is unclear. We tested the effects of energy as EAA or carbohydrate, combined with an EAA-enriched whey protein, on postexercise MPS (%·h -1 ) and whole-body protein turnover (g protein·240 min -1 ).

Exogenous erythropoietin increases hematological status, fat oxidation, and aerobic performance in males following prolonged strenuous training.

This study investigated the effects of EPO on hemoglobin (Hgb) and hematocrit (Hct), time trial (TT) performance, substrate oxidation, and skeletal muscle phenotype throughout 28 days of strenuous exercise. Eight males completed this longitudinal controlled exercise and feeding study using EPO (50 IU/kg body mass) 3×/week for 28 days. Hgb, Hct, and TT performance were assessed PRE and on Days 7, 14, 21, and 27 of EPO.

Pioglitazone does not enhance exogenous glucose oxidation or metabolic clearance rate during aerobic exercise in men under acute high-altitude exposure.

Insulin insensitivity decreases exogenous glucose oxidation and metabolic clearance rate (MCR) during aerobic exercise in unacclimatized lowlanders at high altitude (HA). Whether use of an oral insulin sensitizer before acute HA exposure enhances exogenous glucose oxidation is unclear. This study investigated the impact of pioglitazone (PIO) on exogenous glucose oxidation and glucose turnover compared with placebo (PLA) during aerobic exercise at HA.

Patient and public involvement to inform priorities and practice for research using existing healthcare data for children's and young people's cancers.

Background: In the United Kingdom, healthcare data is collected on all patients receiving National Health Service (NHS) care, including children and young people (CYP) with cancer. This data is used to inform service delivery, and with special permissions used for research. The use of routinely collected health data in research is an advancing field with huge potential benefit, particularly in CYP with cancer where case numbers are small and the impact across the life course can be significant.

Metabolic Adaptations and Substrate Oxidation are Unaffected by Exogenous Testosterone Administration during Energy Deficit in Men.

Introduction/purpose: The effects of testosterone on energy and substrate metabolism during energy deficit are unknown. The objective of this study was to determine the effects of weekly testosterone enanthate (TEST; 200 mg·wk -1 ) injections on energy expenditure, energy substrate oxidation, and related gene expression during 28 d of energy deficit compared with placebo (PLA).

Methods: After a 14-d energy balance phase, healthy men were randomly assigned to TEST ( n = 24) or PLA ( n = 26) for a 28-d controlled diet- and exercise-induced energy deficit (55% below total energy needs by reducing energy intake and increasing physical activity).

Carbohydrate intake in recovery from aerobic exercise differentiates skeletal muscle microRNA expression.

Posttranscriptional regulation by microRNA (miRNA) facilitates exercise and diet-induced skeletal muscle adaptations. However, the impact of diet on miRNA expression during postexercise recovery remains unclear. The objective of this study was to examine the effects of consuming carbohydrate or a nutrient-free control on skeletal muscle miRNA expression during 3 h of recovery from aerobic exercise.

Evaluation of subsurface transport processes of delayed gas signatures applicable to underground nuclear explosions.

Radioactive gas signatures from underground nuclear explosions (UNEs) result from gas-migration processes occurring in the subsurface. The processes considered in this study either drive or retard upward migration of gases from the detonation cavity. The relative importance of these processes is evaluated by simulating subsurface transport in a dual-permeability medium for the multi-tracer Noble Gas Migration Experiment (NGME) originally intended to study some aspects of transport from a UNE.

Circulating and skeletal muscle microRNA profiles are more sensitive to sustained aerobic exercise than energy balance in males.

MicroRNAs (miRNAs) regulate molecular processes governing muscle metabolism. Physical activity and energy balance influence both muscle anabolism and substrate metabolism, but whether circulating and skeletal muscle miRNAs mediate those effects remains unknown. This study assessed the impact of sustained physical activity with participants in energy balance (BAL) or deficit (DEF) on circulating and skeletal muscle miRNAs.

Initial military training modulates serum fatty acid and amino acid metabolites.

Initial military training (IMT) results in increased fat-free mass (FFM) and decreased fat mass (FM). The underlying metabolic adaptations facilitating changes in body composition during IMT are unknown. The objective of this study was to assess changes in body composition and the serum metabolome during 22-week US Army IMT.

A Food-Based Intervention in a Military Dining Facility Improves Blood Fatty Acid Profile.

Enhancing dietary omega-3 highly unsaturated fatty acids (n-3 HUFA) intake may confer neuroprotection, brain resiliency, improve wound healing and promote cardiovascular health. This study determined the efficacy of substituting a few common foods (chicken meat, chicken sausage, eggs, salad dressings, pasta sauces, cooking oil, mayonnaise, and peanut butter) lower in omega-6 polyunsaturated fatty acids (n-6 PUFA) and higher in n-3 HUFA in a dining facility on blood fatty acid profile. An eight-week prospective, between-subjects ( = 77), repeated measures, parallel-arm trial was conducted.

Initiating aerobic exercise with low glycogen content reduces markers of myogenesis but not mTORC1 signaling.

Background: The effects of low muscle glycogen on molecular markers of protein synthesis and myogenesis before and during aerobic exercise with carbohydrate ingestion is unclear. The purpose of this study was to determine the effects of initiating aerobic exercise with low muscle glycogen on mTORC1 signaling and markers of myogenesis.

Methods: Eleven men completed two cycle ergometry glycogen depletion trials separated by 7-d, followed by randomized isocaloric refeeding for 24-h to elicit low (LOW; 1.

Body composition changes in physically active individuals consuming ketogenic diets: a systematic review.

Background: To achieve ideal strength/power to mass ratio, athletes may attempt to lower body mass through reductions in fat mass (FM), while maintaining or increasing fat-free mass (FFM) by manipulating their training regimens and diets. Emerging evidence suggests that consumption of high-fat, ketogenic diets (KD) may be advantageous for reducing body mass and FM, while retaining FFM.

Methods: A systematic review of the literature was conducted using PubMed and Cochrane Library databases to compare the effects of KD versus control diets (CON) on body mass and composition in physically active populations.

Essential amino acid-enriched whey enhances post-exercise whole-body protein balance during energy deficit more than iso-nitrogenous whey or a mixed-macronutrient meal: a randomized, crossover study.

Background: The effects of ingesting varying essential amino acid (EAA)/protein-containing food formats on protein kinetics during energy deficit are undetermined. Therefore, recommendations for EAA/protein food formats necessary to optimize both whole-body protein balance and muscle protein synthesis (MPS) during energy deficit are unknown. We measured protein kinetics after consuming iso-nitrogenous amounts of free-form essential amino acid-enriched whey (EAA + W; 34.

Energy deficit increases hepcidin and exacerbates declines in dietary iron absorption following strenuous physical activity: a randomized-controlled cross-over trial.

Background: Strenuous physical activity promotes inflammation and depletes muscle glycogen, which may increase the iron regulatory hormone hepcidin. Hepcidin reduces dietary iron absorption and may contribute to declines in iron status frequently observed following strenuous physical activity.

Objectives: To determine the effects of strenuous physical activity on hepcidin and dietary iron absorption and whether energy deficit compared with energy balance modifies those effects.

High-Fat Ketogenic Diets and Physical Performance: A Systematic Review.

Use of high-fat, ketogenic diets (KDs) to support physical performance has grown in popularity over recent years. While these diets enhance fat and reduce carbohydrate oxidation during exercise, the impact of a KD on physical performance remains controversial. The objective of this work was to assess the effect of KDs on physical performance compared with mixed macronutrient diets [control (CON)].

Effects of high versus standard essential amino acid intakes on whole-body protein turnover and mixed muscle protein synthesis during energy deficit: A randomized, crossover study.

Background & Aims: Consuming 0.10-0.14 g essential amino acids (EAA)/kg/dose (0.

Cavity-melt partitioning of refractory radionuclides and implications for detecting underground nuclear explosions.

Isotopic ratios of radioxenon captured in the atmosphere can be indicators of the occurrence of an underground nuclear explosion. However, civilian sources of xenon isotopes, such as medical isotope production facilities and nuclear reactors, can interfere with detection of signals associated with nuclear testing, according to a standard model of the evolution of radioxenon isotopic abundances in a nuclear explosion cavity. We find that this standard model is idealized by not including the effects of physical processes resulting in the partitioning of the radionuclide inventory between a gas phase and rock melt created by the detonation and by ignoring seepage or continuous leakage of gases from the cavity or zone of collapse.

Acute hypoxia reduces exogenous glucose oxidation, glucose turnover, and metabolic clearance rate during steady-state aerobic exercise.

Background: Exogenous carbohydrate oxidation is lower during steady-state aerobic exercise in native lowlanders sojourning at high altitude (HA) compared to sea level (SL). However, the underlying mechanism contributing to reduction in exogenous carbohydrate oxidation during steady-state aerobic exercise performed at HA has not been explored.

Objective: To determine if alterations in glucose rate of appearance (R), disappearance (R) and metabolic clearance rate (MCR) at HA provide a mechanism for explaining the observation of lower exogenous carbohydrate oxidation compared to during metabolically-matched, steady-state exercise at SL.

Exercising with low muscle glycogen content increases fat oxidation and decreases endogenous, but not exogenous carbohydrate oxidation.

Background: Initiating aerobic exercise with low muscle glycogen content promotes greater fat and less endogenous carbohydrate oxidation during exercise. However, the extent exogenous carbohydrate oxidation increases when exercise is initiated with low muscle glycogen is unclear.

Purpose: Determine the effects of muscle glycogen content at the onset of exercise on whole-body and muscle substrate metabolism.