Search Results (179)

Background/Objectives: This study aimed to identify the functional adaptations that enable competitive performance in a Paralympic cyclist with optimized bilateral transtibial prostheses compared to a conventional cyclist. Additionally, it describes the development of the prosthesis, designed through a user-centered engineering process incorporating Quality Function Deployment (QFD), Computer-Aided Design (CAD), Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), and topological optimization, with the final design (Design 1.4) achieving optimal structural integrity, aerodynamic efficiency, and anatomical fit. Methods: Both athletes performed a progressive cycling test with 50-watt increments every three minutes until exhaustion. Cardiorespiratory metrics, lactate thresholds, and joint kinematics were assessed. Results: Although the conventional cyclist demonstrated higher Maximal Oxygen Uptake (VO₂max) and anaerobic threshold, the Paralympic cyclist exceeded 120% of his predicted VO₂max, had a higher Respiratory Exchange Ratio (RER) [1.32 vs. 1.11], and displayed greater joint ranges of motion with lower trunk angular variability. Lactate thresholds were similar between athletes. Conclusions: These findings illustrate, in this specific case, that despite lower aerobic capacity, the Paralympic cyclist achieved comparable performance through efficient biomechanical and physiological adaptations. Integrating advanced prosthetic design with individualized evaluation appears essential to optimizing performance in elite adaptive cycling. Full article

Background: Maintaining thermal homeostasis is a basic function of the human body. This homeostasis depends largely on the body’s nutritional status and other conditions related to it. Aim: The present study investigated the impact of 8 days of water-only fasting (8DW-F) on selected features of thermal homeostasis, taking into account somatic, metabolic, and circulatory changes in middle-aged men. Methods: A total of 13 healthy men took part in the experiment. Volunteers were examined twice: after a mixed diet (C) and after using 8DW-F. At baseline, the following were recorded: body mass (BM), body fat (FM), fat-free mass (FFM), and total water (TBW), along with basal metabolic rate (BMR) and body surface area (BSA). Then, after 30 min of sitting under thermoneutral conditions, the following measurements were taken: eardrum temperature (Ti), skin temperatures (Tsk), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), oxygen uptake (VO₂), and respiratory exchange ratio (RER). The following were then calculated: average body (MTB) and skin temperature (MTsk), resting metabolic rate (RMR), body to skin temperature gradient (g), and whole-body thermal conductivity (C). Results: The results showed that 8DW-F cause a significant reduction in most somatic variables as well as SBP and BMR (p < 0.001), RMR (p < 0.05) with no changes in Ti, MTsk, MTB, or C and g (p = 0.09). There were also significant correlations between Δ MTB × Δ BMR (p < 0.05) and Δ RMR × Δ VO₂ (p < 0.001). Moreover, changes in the C range correlated with Δ RMR (p < 0.005) and Δ DBP (p < 0.05). Conclusions: 8DW-F reduced resting metabolic heat production in the studied men, but sufficient heat conservation ensured that thermal homeostasis was maintained under thermally neutral conditions. Full article

Objective: This study aimed to compare trained male and female athletes regarding physiological, perceptual, and performance variables at ventilatory thresholds (VT₁ and VT₂). Methods: Twenty-four male and nineteen female trained runners (age: 27.9 ± 6.4 vs. 24.4 ± 4.4 years; body mass: 61.8 ± 4.3 vs. 52.6 ± 4.1 kg; height: 174.6 ± 5.8 vs. 165.0 ± 5.0 cm for males and females, respectively) performed a graded exercise test to exhaustion on a treadmill. During the test, oxygen consumption, respiratory exchange ratio, running power output, heart rate, muscle oxygenation, and rate of perceived exertion were analyzed. Sex differences were evaluated with an unpaired-samples t-test. Results: Males exhibited significantly higher respiratory exchange ratios (0.87 ± 0.04 vs. 0.83 ± 0.03; 1.03 ± 0.06 vs. 1.01 ± 0.06) and absolute running speeds (15.00 ± 1.06 vs. 12.42 ± 1.22 km·h⁻¹; 19.04 ± 1.06 vs. 16.32 ± 1.29 km·h⁻¹) at both thresholds (p < 0.05), whereas women showed higher muscle oxygenation in vastus lateralis (60.44 ± 21.21 vs. 26.38 ± 10.21%) and fractional utilization of maximal aerobic speed (93.64 ± 6.44 vs. 91.43 ± 3.21%) at VT₂ (p < 0.01). Also, rate of perceived exertion was similar between sexes at both thresholds. Conclusion: Males showed higher absolute physiological values, while females demonstrated greater fractional utilization at VT₂ and higher muscle oxygenation. No sex differences were observed in rate of perceived exertion. These findings highlight the importance of using ventilatory thresholds in training prescription. Full article

Background/Objectives: Mechanical ventilation is essential in the management of acute respiratory failure (RF); however, prolonged use increases the risk of complications. Accurate predictors are therefore needed to guide timely weaning. The Rapid Shallow Breathing Index (RSBI), the dead space to tidal volume ratio (VD/VT), and the Integrative Weaning Index (IWI) are among the key indices used to assess weaning readiness. This study aimed to examine whether these indices differ between patients with Type 1 (hypoxemic) and Type 2 (hypercapnic) respiratory failure who were successfully extubated in the emergency department, in order to explore their physiologic variability across respiratory failure phenotypes. Methods: This cross-sectional study included 35 adult patients (23 with Type 1 RF, 12 with Type 2 RF) who were successfully weaned from mechanical ventilation in the Emergency Department of a tertiary care hospital between 2022 and 2024. RSBI, VD/VT, IWI, and arterial blood gas parameters were recorded. Descriptive and comparative statistical analyses were performed, with significance set at p < 0.05. Results: There were no significant differences in age, gender, or comorbidities between the groups. Type 2 RF patients had higher FiO₂ requirements (37.5% vs. 30.0%; p = 0.03) and PaCO₂ levels (49.1 ± 9.65 mmHg vs. 40.3 ± 4.49 mmHg; p < 0.001). The PaO₂/FiO₂ ratio was lower in the Type 2 group (169 ± 49.6) compared to the Type 1 group (244 ± 95.6; p = 0.017). VD/VT ratios were significantly higher in Type 2 RF patients (0.37 ± 0.04 vs. 0.29 ± 0.13; p = 0.046). RSBI values were identical between groups (40.0 in both; p = 1.00), and IWI values showed no significant difference (70.8 ± 30.7 vs. 79.3 ± 32.5; p = 0.45). Conclusions: Although RSBI and IWI values were similar across respiratory failure types, patients with Type 2 RF demonstrated higher VD/VT ratios and lower PaO₂/FiO₂, indicating reduced gas exchange and alveolar ventilation efficiency. These findings suggest that VD/VT may be a more useful parameter for assessing weaning readiness in hypercapnic patients. Full article

In placental mammals, the co-option of vertebrate orthologous ATP1B4 genes has profoundly altered the properties of the encoded BetaM proteins, which function as bona fide β-subunits of Na,K-ATPases in lower vertebrates. Eutherian BetaM acquired an extended Glu-rich N-terminal domain resulting in the complete loss of its ancestral function and became a skeletal and cardiac muscle-specific component of the inner nuclear membrane. BetaM is expressed at the highest level during perinatal development and is implicated in gene regulation. Here we report the long-term consequences of Atp1b4 ablation on metabolic parameters in adult mice. Male BetaM-deficient (Atp1b4−/Y) mice have remarkably lower body weight and adiposity than their wild-type littermates, despite higher food intake. Indirect calorimetry shows higher energy expenditure (heat production and oxygen consumption) with a greater spontaneous locomotor activity in Atp1b4−/Y males. Their lower respiratory exchange ratio suggests a greater reliance on fat metabolism compared to their wild-type counterparts. Consistently, Atp1b4−/Y KO mice exhibit enhanced β-oxidation in skeletal muscle, along with improved glucose and insulin tolerance. These robust metabolic changes induced by Atp1b4 disruption demonstrate that eutherian BetaM plays an important role in regulating adult mouse metabolism. This demonstrates that bypassing the co-option of Atp1b4 potentially reduces susceptibility to obesity. Thus, Atp1b4 ablation leading to the loss of evolutionarily acquired BetaM functions serves as a model for a potential alternative pathway in mammalian evolution. Full article

Background: Cardiopulmonary exercise testing (CPET) is a valuable diagnostic and prognostic tool for assessing the integrated function of the cardiopulmonary and muscular systems during exercise. The initiation of a CPET program is complex, and data on early implementation in academic centers remain relatively limited. Objective: to evaluate the initial integration of CPET within a pulmonary department, focusing on patient demographics, referral indications, test performance, and factors associated with anaerobic threshold achievement. Methods: A retrospective cohort study was conducted at a single tertiary care center, including all patients who underwent their first CPET between February 2016 and December 2022. Demographic, clinical, and functional parameters were extracted. Multivariable logistic regression was used to identify variables associated with anaerobic threshold achievement, defined as a respiratory exchange ratio (RER) ≥ 1.1. Results: The cohort included 434 patients (mean age 60.3 ± 14.1 years; 54% male; mean BMI 29.2 ± 5.6 kg/m²). The most common indication for testing was dyspnea (50%). Tests were most frequently terminated due to leg discomfort (39%) and dyspnea (38.8%). Achievement of RER ≥ 1.1 was independently associated with lower BMI (aOR = 0.91; 95% CI: 0.88–0.95; p < 0.001), higher FVC % predicted (aOR = 1.02; 95% CI: 1.00–1.03; p = 0.028), and greater minute ventilation volume (aOR = 1.02; 95% CI: 1.01–1.03; p < 0.001), and it was less likely in patients referred for cardiovascular disease (aOR = 0.37; 95% CI: 0.21–0.64; p < 0.001). No consistent temporal trend in RER achievement was observed across the study period. Conclusions: CPET was most commonly utilized in response to patient-reported dyspnea, with test termination frequently driven by subjective symptoms rather than objective clinical criteria. Anaerobic threshold achievement was more strongly associated with individual physiological characteristics than with institutional experience. These findings underscore the importance of patient preparation and pulmonary functional capacity in optimizing CPET performance. Full article

Background: The accuracy of measurement of cardiometabolic outcomes in terms of gaseous exchange and energy expenditure of individuals is crucial. The objective of this study was to compare the validity and reliability of the PNO$\overline{\mathrm{E}}$ in measuring cardiometabolic outcomes from the respiratory gaseous exchange of healthy individuals during treadmill walking exercise. Methods: A total of 21 healthy subjects (15 male and 6 female) aged 22.76 ± 3.85 years took part in this study. Oxygen uptake (VO₂), carbon dioxide production (VCO₂), respiratory exchange ratio (RER), metabolic equivalents (METs), tidal volume (VT), and energy expenditure (EE) were measured using the PNO$\overline{\mathrm{E}}$ and COSMED K5 portable systems during a twenty-eight-minute, four-stage incremental protocol, where speed increased from 1.7 mph to 4.2 mph with a 2% incline on a treadmill. Test–retest reliability was tested on separate days with trail repetition. Validity was evaluated by Bland–Altman plots, intraclass correlation coefficients (ICCs) and mean percentage difference. Results: ICCs showed that VCO₂ was in the good range (0.75–0.90). The ICC of the RER from stages 1 to 3 of the incremental protocol and the VT from stages 2 to 4 of the incremental protocol showed good to excellent reliability. No clear trend was seen for VO₂, VCO₂, and EE datapoints with variations in speed. Pearson’s correlation coefficients were moderately high (r = 0.60–0.79) between VO₂, VCO₂, RER, METs, VT, and EE measured by the PNO$\overline{\mathrm{E}}$ and K5 systems. All subjects, except for a few cases in VT, were within the upper and lower 95% confidence intervals of the acceptable range of the Bland–Altman plots. Conclusions: The PNO$\overline{\mathrm{E}}$ system is a valid and reliable measure of cardiometabolic outcomes and is comparable to the COSMED K5 system. Full article

Type 2 diabetes and prediabetes are associated with a higher risk of several health conditions. We conducted a cross-sectional study to compare the prevalence of comorbidities among 88,724 adults with prediabetes and 12,071 adults with type 2 diabetes in El Paso, Texas, using data from the Paso del Norte Health Information Exchange (PHIX) from 1 January 2021, to 31 January 2023. We estimated prevalence ratios (aPR) adjusted for age decade, gender, and Hispanic ethnicity. Individuals with prediabetes, compared to type 2 diabetes, had lower adjusted prevalence of circulatory (59.1% vs. 80.4%; aPR = 0.82 [95% CI: 0.81–0.84]), genitourinary (44.9% vs. 50.5%; aPR = 0.97 [0.96–0.99]), respiratory (32.0% vs. 35.7%; aPR = 0.94 [0.92–0.97]), neurological (27.4% vs. 32.8%; aPR = 0.91 [0.88–0.94]), blood (21.2% vs. 30.5%; aPR = 0.77 [0.75–0.80]), mental (19.5% vs. 26.1%; aPR = 0.72 [0.69–0.75]), infectious (12.8% vs. 21.5%; aPR = 0.63 [0.60–0.66]), skin (12.2% vs. 14.8%; aPR = 0.82 [0.78–0.86]), and COVID-19 (10.2% vs. 11.9%; aPR = 0.86 [0.81–0.91]) diseases/conditions. Adjusted prevalence was higher among those with prediabetes for musculoskeletal (53.8% vs. 47.0%; aPR = 1.19 [1.17, 1.21]), ear (18.4% vs. 12.9%; aPR = 1.54 [1.47–1.60]), eye (11.1% vs. 7.8%; aPR = 1.52 [1.43, 1.61]), digestive (44.0% vs. 44.0%; aPR = 1.02 [1.00–1.05]), and neoplastic (14.4% vs. 14.5%; aPR = 1.12 [1.06–1.17]) diseases/conditions. People with prediabetes in El Paso, Texas, had a lower prevalence of most comorbidities than those with type 2 diabetes, suggesting that preventing prediabetes from progressing to type 2 diabetes could have a beneficial impact on comorbid disease burden. Full article

Objective: Prolonged microgravity environments impair skeletal muscle homeostasis by triggering fiber-type transitions and metabolic dysregulation. Although exercise and nutritional interventions may alleviate disuse atrophy, their synergistic effects under microgravity conditions remain poorly characterized. This study investigated the effects of an 8-week ketogenic diet combined with aerobic exercise in hindlimb-unloaded mice on muscle fiber remodeling and metabolic adaptation. Methods: Seven-week-old male C57BL/6J mice were randomly divided into six groups: normal diet control (NC), normal diet with hindlimb unloading (NH), normal diet with hindlimb unloading and exercise (NHE), ketogenic diet control (KC), ketogenic diet with hindlimb unloading (KH), and ketogenic diet with hindlimb unloading and exercise (KHE). During the last two weeks of intervention, hindlimb unloading was applied to simulate microgravity. Aerobic exercise groups performed moderate-intensity treadmill running (12 m/min, 60 min/day, and 6 days/week) for 8 weeks. Body weight, blood ketone, and glucose levels were measured weekly. Post-intervention assessments included the respiratory exchange ratio (RER), exhaustive exercise performance tests, and biochemical analyses of blood metabolic parameters. The skeletal muscle fiber-type composition was evaluated via immunofluorescence staining, lipid deposition was assessed using Oil Red O staining, glycogen content was analyzed by Periodic Acid–Schiff (PAS) staining, and gene expression was quantified using quantitative real-time PCR (RT-qPCR). Results: Hindlimb unloading significantly decreased body weight, induced muscle atrophy, and reduced exercise endurance in mice. However, the combination of KD and aerobic exercise significantly attenuated these adverse effects, as evidenced by increased proportions of oxidative muscle fibers (MyHC-I) and decreased proportions of glycolytic fibers (MyHC-IIb). Additionally, this combined intervention upregulated the expression of lipid metabolism-associated genes, including CPT-1b, HADH, PGC-1α, and FGF21, enhancing lipid metabolism and ketone utilization. These metabolic adaptations corresponded with improved exercise performance, demonstrated by the increased time to exhaustion in the KHE group compared to other hindlimb unloading groups. Conclusions: The combination of a ketogenic diet and aerobic exercise effectively ameliorates simulated microgravity-induced skeletal muscle atrophy and endurance impairment, primarily by promoting a fiber-type transition from MyHC-IIb to MyHC-I and enhancing lipid metabolism gene expression (CPT-1b, HADH, and PGC-1α). These findings underscore the potential therapeutic value of combined dietary and exercise interventions for mitigating muscle atrophy under simulated microgravity conditions. Full article

The adrenergic system plays an active role in modulating synaptic transmission in hypothalamic neurocircuitry. While α2-adrenergic receptors are widely distributed in various organs and are involved in various physiological functions, their specific role in the regulation of energy metabolism in the brain remains incompletely understood. Herein, we investigated the functions of α2-adrenergic receptors in the hypothalamus on energy metabolism in mice. Our study confirmed the expression of α2-adrenergic receptors in hypothalamic dopaminergic neurons and assessed metabolic phenotypes, including food intake and energy expenditure, after treatment with guanabenz, an α2-adrenergic receptor agonist. Guanabenz treatment significantly increased food intake (0.25 ± 0.03 g vs. 0.98 ± 0.05 g, p < 0.001) and body weight (−0.1 ± 0.04 g vs. 0.33 ± 0.03 g, p < 0.001) within 6 h post-treatment. Furthermore, guanabenz markedly elevated energy expenditure parameters, including respiratory exchange ratio (RER, 1.017 ± 0.007 vs. 1.113 ± 0.03, p < 0.01) and carbon dioxide production (1.512 ± 0.018 mL/min vs. 1.635 ± 0.036 mL/min, p < 0.05), compared to vehicle-treated controls. Furthermore, using chemogenetic techniques, we demonstrated that the altered metabolic phenotypes induced by guanabenz treatment were effectively reversed by inhibiting the activity of dopaminergic neurons in the hypothalamic arcuate nucleus (ARC) using a chemogenetic technique. Our findings suggest functional connectivity between hypothalamic α2-adrenergic receptor signals and dopaminergic neurons in metabolic controls. Full article

We recently reported that a chimeric peptide (GEP44) targeting the glucagon-like peptide-1 receptor (GLP-1R) and neuropeptide Y1- and Y2- receptors decreased body weight (BW), energy intake, and core temperature in diet-induced obese (DIO) male and female mice. In the current study, we tested the hypothesis that the strong reduction in body weight in response to GEP44 is partially related to the stimulation of energy expenditure (EE). To test this, rats were maintained on a high fat diet (HFD) for at least 4 months to elicit DIO prior to undergoing a sequential 2-day vehicle period, 2-day GEP44 (50 nmol/kg) period, and a minimum 2-day washout period, and detailed measures of energy homeostasis. GEP44 (50 nmol/kg) reduced EE (indirect calorimetry), respiratory exchange ratio (RER), core temperature, activity, energy intake, and BW in male and female rats. As in our previous study in mice, GEP44 reduced BW in male and female HFD-fed rats by 3.8 ± 0.2% and 2.3 ± 0.4%, respectively. These effects appear to be mediated by increased lipid oxidation and reductions in energy intake as GEP44 reduced RER and cumulative energy intake in male and female HFD-fed rats. The strong reduction in body weight in response to GEP44 is related to a robust reduction in energy intake, but not to the stimulation of EE. The paradoxical finding that GEP44 reduced EE might be secondary to a reduction in diet-induced thermogenesis or might indicate an important mechanism to limit the overall efficacy of GEP44 to prevent further weight loss. Full article

Background/Objectives: Managing ventilatory strategies in patients with obesity under general anesthesia presents significant challenges due to obesity-related pathophysiological changes. Inverse ratio ventilation (IRV) has emerged as a potential strategy to optimize respiratory mechanics during laparoscopic surgery in this population. The primary outcomes were changes in respiratory mechanics, including peak inspiratory pressure (P_Peak), plateau pressure (P_Plat), mean airway pressure (P_Mean), and dynamic compliance (C_Dyn). Secondary outcomes included gas exchange parameters, hemodynamic measures, inflammatory cytokines, and postoperative complications. Methods: A systematic review and meta-analysis were conducted, searching PubMed, Scopus, EMBASE, and PMC Central. Only English-language randomized controlled trials (RCTs) evaluating the impact of IRV in adult surgical patients with obesity were included. The quality and certainty of evidence were assessed using the Risk of Bias 2 (RoB 2) tool and the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework, respectively. Results: Three RCTs including 172 patients met the inclusion criteria. Compared to conventional ventilation without prolonged inspiratory time or IRV, IRV significantly reduced P_Peak (MD [95%CI]: −3.15 [−3.88; −2.42] cmH₂O, p < 0.001) and P_Plat (MD [95%CI]: −3.13 [−3.80; −2.47] cmH₂O, p < 0.001) while increasing P_Mean (MD [95%CI]: 4.17 [3.11; 5.24] cmH₂O, p < 0.001) and C_Dyn (MD [95%CI]: 2.64 [0.95; 4.22] mL/cmH₂O, p = 0.002) during laparoscopy, without significantly affecting gas exchange. IRV significantly reduced mean arterial pressure (MD [95%CI]: −2.93 [−3.95; −1.91] mmHg, p < 0.001) and TNF-α levels (MD [95%CI]: −9.65 [−17.89; −1.40] pg/mL, p = 0.021). Conclusions: IRV optimizes intraoperative respiratory mechanics but has no significant impact on postoperative outcomes, necessitating further research to determine its clinical role. Full article

Background/Objectives: Our studies have provided evidence for the alteration of exercise-induced metabolic responses by the intake of anthocyanin-rich New Zealand blackcurrant (NZBC) extract. In this secondary analysis of 10 studies, we examined the relationship between the pre-intervention exercise-induced respiratory exchange ratio and the blackcurrant-induced respiratory exchange ratio and substrate utilisation during exercise. Methods: Metabolic data of seven cohort and three case studies with females (n = 46) and males (n = 71), from recreationally active to ultra-endurance trained individuals that were dosed with different intake durations (acute to two-week intake) and dosages (105 to 420 mg of anthocyanins) of NZBC extract for walking-, running-, and cycling-induced effects, were included in the secondary analysis. Results: There was a strong positive correlation between the pre-intervention and blackcurrant-induced respiratory exchange ratio for females (Pearson r: 0.7972, p < 0.0001) and males (Pearson r: 0.8674, p < 0.0001). A moderate positive correlation was obtained for the relationship between the pre-intervention respiratory exchange ratio and changes in fat oxidation for females (Pearson r: 0.5311, p = 0.0001) and males (Pearson r: 0.3136, p = 0.002). In addition, a moderate negative correlation was obtained for the relationship between the pre-intervention respiratory exchange ratio and changes in carbohydrate oxidation for females (Pearson r: −0.3017, p = 0.0393) and males (Pearson r: −0.3327, p < 0.001). There were no differences between females and males in the changes of the exercise-induced metabolic responses to the intake of New Zealand blackcurrant extract. Conclusions: Our secondary analysis of the data in studies on the effects of New Zealand blackcurrant extract suggests that the metabolic response of individuals to the intake of New Zealand blackcurrant extract depends partly on the pre-intervention respiratory exchange ratio, with the majority of individuals showing enhanced exercise-induced fat oxidation and lower exercise-induced carbohydrate oxidation. However, a divergent metabolic response seems possible such that individuals with a very low intrinsic respiratory exchange ratio may more likely experience lower fat oxidation and higher carbohydrate oxidation with the intake of New Zealand blackcurrant. Individuals with a high intrinsic respiratory exchange will more likely experience higher fat oxidation and lower carbohydrate oxidation with the intake of New Zealand blackcurrant. Future work is required to examine the factors and mechanisms for the individual variation of the response of exercise-induced substrate utilisation relative to the intake of anthocyanin-rich New Zealand blackcurrant extracts. Full article

Background/Objective: Attention should be paid to the introduction of more functional training methods during the second stage of cardiac rehabilitation, which imitate everyday activities to some extent. The main purpose of this research was to analyze the effects of a 22-day training program carried out in normobaric hypoxic conditions corresponding to the altitude of 3000 m a.s.l. in patients after myocardial infarction and to compare it with the same training conducted in normoxic conditions. Material and Methods: This study included 36 patients after myocardial infarction who underwent percutaneous angioplasty with stent implantation. They were examined before and after 2 days of training sessions: day one, spiroergometric exercise test on a mechanical treadmill, blood collection for laboratory tests; day two, echocardiography of the heart. Than patients underwent 22 days of training in hypoxic conditions. At the end of experiment patients had the same examinations as day one and two. Results: Training conducted in hypoxic conditions had a wider impact on spiroergometrical parameters. Significant, beneficial changes were demonstrated in relation to test duration, distance covered, energy expenditure MET, respiratory exchange ratio RER, as well as resting values of systolic and diastolic blood pressure. There were no changes in parameters for morphology, cytokines, and fibrinogen. There were some differences in relation to echocardiography examinations. Conclusions: The conditions in which the rehabilitation training was conducted affect the level of exercise tolerance. The hypoxic conditions in which the training was conducted affected only two hemodynamic parameters: LVESd and e’ septal. Rehabilitation training conducted in various environmental conditions had an impact only on the IL-10 value. Full article

Background/Objectives: Low energy availability (LEA) can cause impaired reproductive function, bone health issues, and suppressed immune function, and may result in decreased performance and overall health status. The purpose of this study was to investigate adaptions of body composition, blood status, resting metabolic rate, and endurance performance to gain more comprehensive insights into the symptoms of LEA and the adaptive effects in the athlete population (active women (n = 11) and men (n = 11)). Methods: Three treatments were defined as 45 (EA45, control), 30 (EA30), and 10 (EA10) kcal/kg FFM/day and randomly assigned. Pre- and post-intervention measurements were performed through blood sampling, bioelectrical impedance analysis, resting metabolic rate measurement, the oral glucose tolerance test (OGTT), and the incremental endurance test to exhaustion. Results: There was a significant reduction in body weight and fat mass in EA10 compared to EA45 (p ≤ 0.05). Blood serum levels were altered in triglyceride, uric acid, and creatinine concentrations in EA10 compared to EA45 (p ≤ 0.05). Furthermore, blood glucose was still accumulated after 120 min during OGTT in EA10 compared to EA45 (p ≤ 0.05). The respiratory exchange ratio was reduced during submaximal stages of the incremental treadmill test to exhaustion without influencing performance output after treatment EA10 (p ≤ 0.05). However, the resting metabolic rate did not change (p > 0.05). Conclusions: In conclusion, this short-term study indicates that energy restriction can lead to several metabolic-related adaptations, which suggests that the availability and regulation of glucose and fats are significantly influenced after only five days of LEA in physically active women and men. Future research should focus on longer exposures of LEA and sex-specific comparisons (including the menstrual cycle) on LEA symptoms. Full article