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).

Longitudinal changes in psychological, physiological, and nutritional measures and predictors of success in Special Forces training.

The mentally and physically challenging 19-20 day, multi-stressor US Army Special Forces Assessment and Selection (SFAS) course selects soldiers for Army Special Forces (SF) training. If selected, candidates enroll for advanced training in the 2-year Special Forces Qualification Course (SFQC) to qualify for the SF. This longitudinal study examined physiological, psychological, and nutritional status of soldiers before (pre-SFAS) and after SFAS (post-SFAS), and post-SFQC, to identify predictors of graduation from SFQC.

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 ).

Associations between Essential Amino Acid Intake and Functional Health Outcomes in Older Adults: Analysis of the National Health and Nutrition Examination Survey, 2001-2018.

Background: The relationships between habitual essential amino acid (EAA) intake and body composition, muscle strength, and physical function in older US adults are not well defined.

Objectives: This cross-sectional study evaluated associations between usual EAA intakes and body composition, muscle strength, and physical function in US adults ≥65 y.

Methods: The Food and Nutrient Database for Dietary Studies (FNDDS) 2001-2018 was linked to the US Department of Agriculture Standard Reference database to access existing amino acid composition data for FNDDS ingredients.

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.

Comparative analysis of circulating metabolomic profiles identifies shared metabolic alterations across distinct multistressor military training exercises.

Military training provides insight into metabolic responses under unique physiological demands that can be comprehensively characterized by global metabolomic profiling to identify potential strategies for improving performance. This study identified shared changes in metabolomic profiles across three distinct military training exercises, varying in magnitude and type of stress. Blood samples collected before and after three real or simulated military training exercises were analyzed using the same untargeted metabolomic profiling platform.

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.

Metabolic Costs of Walking with Weighted Vests.

Introduction: The US Army Load Carriage Decision Aid (LCDA) metabolic model is used by militaries across the globe and is intended to predict physiological responses, specifically metabolic costs, in a wide range of dismounted warfighter operations. However, the LCDA has yet to be adapted for vest-borne load carriage, which is commonplace in tactical populations, and differs in energetic costs to backpacking and other forms of load carriage.

Purpose: The purpose of this study is to develop and validate a metabolic model term that accurately estimates the effect of weighted vest loads on standing and walking metabolic rate for military mission-planning and general applications.

Effects of testosterone enanthate on aggression, risk-taking, competition, mood, and other cognitive domains during 28 days of severe energy deprivation.

Rationale: Behavioral effects of testosterone depend on dose, acute versus sustained formulation, duration of administration, personality, genetics, and endogenous levels of testosterone. There are also considerable differences between effects of endogenous and exogenous testosterone.

Objectives: This study was the secondary behavioral arm of a registered clinical trial designed to determine if testosterone protects against loss of lean body mass and lower-body muscle function induced by a severe energy deficit typical of sustained military operations.

Replacement of dietary carbohydrate with protein increases fat mass and reduces hepatic triglyceride synthesis and content in female obese Zucker rats.

Previous studies have demonstrated both energy restriction (ER) and higher protein (HP), lower carbohydrate (LC) diets downregulate hepatic de novo lipogenesis. Little is known about the independent and combined impact of ER and HP/LC diets on tissue-specific lipid kinetics in leptin receptor-deficient, obese rodents. This study investigated the effects of ER and dietary macronutrient content on body composition; hepatic, subcutaneous adipose tissue (SAT), and visceral AT (VAT) lipid metabolic flux ( H O-labeling); and blood and liver measures of cardiometabolic health in six-week-old female obese Zucker rats (Lepr ).

International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance.

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them.

Exercise for optimizing bone health after hormone-induced increases in bone stiffness.

Hormones and mechanical loading co-regulate bone throughout the lifespan. In this review, we posit that times of increased hormonal influence on bone provide opportunities for exercise to optimize bone strength and prevent fragility. Examples include endogenous secretion of growth hormones and sex steroids that modulate adolescent growth and exogenous administration of osteoanabolic drugs like teriparatide, which increase bone stiffness, or its resistance to external forces.

High-fat ketogenic diets and ketone monoester supplements differentially affect substrate metabolism during aerobic exercise.

Chronically adhering to high-fat ketogenic diets or consuming ketone monoester supplements elicits ketosis. Resulting changes in substrate metabolism appear to be drastically different between ketogenic diets and ketone supplements. Consuming a ketogenic diet increases fatty acid oxidation with concomitant decreases in endogenous carbohydrate oxidation.

Daily Naltrexone Use Does Not Adversely Affect Physical, Cognitive or Marksmanship Performance in U.S. Army Soldiers.

Introduction: Considering the potential of weaponized opioids, evaluating how prophylactic countermeasures affect military-relevant performance is necessary. Naltrexone is a commercially available Food and Drug Administration-approved medication that blocks the effects of opioids with minimal side effects. However, the effects of naltrexone on the health and performance of non-substance abusing military personnel are not well described in the existing literature.

Low carbohydrate availability impairs hypertrophy and anaerobic performance.

Purpose Of Review: Highlight contemporary evidence examining the effects of carbohydrate restriction on the intracellular regulation of muscle mass and anaerobic performance.

Recent Findings: Low carbohydrate diets increase fat oxidation and decrease fat mass. Emerging evidence suggests that dietary carbohydrate restriction increases protein oxidation, thereby limiting essential amino acid availability necessary to stimulate optimal muscle protein synthesis and promote muscle recovery.

Biomarkers of oxidative stress, diet and exercise distinguish soldiers selected and non-selected for special forces training.

Introduction: The metabolomic profiles of Soldiers entering the U.S. Special Forces Assessment and Selection course (SFAS) have not been evaluated.

Bioelectrical impedance phase angle is associated with physical performance before but not after simulated multi-stressor military operations.

Physical performance decrements observed during multi-stressor military operations may be attributed, in part, to cellular membrane dysfunction, which is quantifiable using phase angle (PhA) derived from bioelectrical impedance analysis (BIA). Positive relationships between PhA and performance have been previously reported in cross-sectional studies and following longitudinal exercise training programs, but whether changes in PhA are indicative of acute decrements in performance during military operations is unknown. Data from the Optimizing Performance for Soldiers II study, a clinical trial examining the effects of exogenous testosterone administration on body composition and performance during military stress, was used to evaluate changes in PhA and their associations with physical performance.

Performance nutrition for cold-weather military operations.

.High daily energy expenditure without compensatory increases in energy intake results in severe energy deficits during cold-weather military operations. The severity of energy deficits has been proportionally linked to declines in body mass, negative protein balance, suppression of androgen hormones, increases in systemic inflammation and degraded physical performance.

Amino Acid Intake and Conformance With the Dietary Reference Intakes in the United States: Analysis of the National Health and Nutrition Examination Survey, 2001-2018.

Background: The lack of complete amino acid composition data in food composition databases has made determining population-wide amino acid intake difficult.

Objectives: This cross-sectional study characterizes habitual intakes of each amino acid and adherence to dietary requirements for each essential amino acid (EAA) in the US population.

Methods: Food and Nutrient Database for Dietary Studies ingredient codes with missing amino acid composition data were matched to similar ingredients with available data so that amino acid composition could be determined for 100% of foods reported in the dietary intake assessment component of NHANES.

Monitoring body composition change for intervention studies with advancing 3D optical imaging technology in comparison to dual-energy X-ray absorptiometry.

Background: Recent 3-dimensional optical (3DO) imaging advancements have provided more accessible, affordable, and self-operating opportunities for assessing body composition. 3DO is accurate and precise in clinical measures made by DXA. However, the sensitivity for monitoring body composition change over time with 3DO body shape imaging is unknown.

Maximizing Strength: The Stimuli and Mediators of Strength Gains and Their Application to Training and Rehabilitation.

Spiering, BA, Clark, BC, Schoenfeld, BJ, Foulis, SA, and Pasiakos, SM. Maximizing strength: the stimuli and mediators of strength gains and their application to training and rehabilitation. J Strength Cond Res 37(4): 919-929, 2023-Traditional heavy resistance exercise (RE) training increases maximal strength, a valuable adaptation in many situations.