Search Results (285)

Background/Objectives: Aging is characterized by progressive physiological and metabolic decline. Aerobic exercise mitigates age-related impairments, and nicotinamide mononucleotide (NMN), a precursor in the NAD⁺ salvage pathway, has emerged as a nutritional intervention to promote healthy aging. This study investigated whether NMN supplementation combined with aerobic exercise provides synergistic benefits on physical performance and metabolic regulation in aged mice. Methods: Forty male C57BL/6J mice, including eight young (8 weeks) and thirty-two aged (85 weeks) mice, were randomly assigned to five groups: young sedentary (YS), aged sedentary (AS), aged with exercise (AE), aged with NMN (ASNMN; 300 mg/kg/day), and aged with combined NMN and exercise (AENMN). Interventions lasted six weeks. Assessments included grip strength, muscle endurance, aerobic capacity, oral glucose tolerance test (OGTT), and indirect calorimetry, followed by biochemical and molecular analyses of NAMPT and SirT1 expression. Results: The AENMN group demonstrated significant improvements in maximal strength and aerobic endurance compared with the AS group (p < 0.05). Both NMN and exercise interventions increased blood NAMPT concentrations, with the highest levels observed in the AENMN group (p < 0.05). SirT1 expression was elevated in the ASNMN and AENMN groups relative to YS (p < 0.05). Glucose tolerance improved in the ASNMN and AENMN groups (p < 0.05). Enhanced energy metabolism in the AENMN group was indicated by increased oxygen consumption, elevated energy expenditure, and reduced respiratory quotient. Conclusions: NMN supplementation, particularly when combined with aerobic exercise, effectively improved aerobic performance, glucose regulation, and systemic energy metabolism in aged mice. These findings suggest that NMN, in synergy with exercise, may serve as a promising nutritional strategy to counteract age-associated metabolic and functional decline. Full article

This study determined the influence of experimental factors such as current density, surface-to-volume ratio (S/V), and contact time on the removal of Chemical Oxygen Demand (COD) and energy consumption during electrocoagulation, aiming to optimize the efficiency of a coaxial electrocoagulator for the co-treatment of municipal wastewater and acid mine drainage. After identifying the optimal volumetric ratio between both types of effluents, a Box–Behnken design and response-surface methodology were employed to identify the conditions that maximize COD removal while minimizing energy consumption. Under optimal conditions (current density of 2.42 A·m⁻², S/V = 300 m²·m⁻³, 60 min), a COD removal of 91.13% was achieved with a specific energy of =2.59 kWh·kgCOD⁻¹. The statistical model for COD removal demonstrated a good fit (R² = 0.87), though its predictive power was limited (predicted R² = 0.53). In contrast, the model for energy consumption exhibited an outstanding fit (R² = 0.99) and high predictive consistency (predicted R² = 0.98), confirming the decisive influence of current density on energy demand. Additionally, the S/V ratio emerged as the most impactful factor in COD removal variability. Overall, the findings highlight the importance of balancing removal efficiency with the economic feasibility of the process, contributing to the design of more sustainable and effective strategies for integrated wastewater treatment. Full article

Cardiopulmonary exercise testing (CPET) is recommended as part of routine care in people with congenital heart disease. A significant difference has been observed in many CPET parameters, depending on the ergometer and exercise protocol used. The aim of this study is to investigate such differences in Fontan patients. All Fontan patients (<40 years old, NYHA class I/I–II) underwent two consecutive CPETs on different ergometers (treadmill with ramped Bruce protocol versus cycle ergometer with ramp protocol) within less than 12 months. The exclusion criterion was the presence of significant clinical/anthropometric changes between the two tests. Anthropometric, surgical, clinical, electrocardiogram (ECG) and CPET data were collected. 47 subjects were enrolled (25 males, mean age 16.4 at first test). Peak heart rate (HR) tended to be higher on the treadmill (p = 0.05 as % of predicted, p = 0.062 in absolute value). Peak oxygen consumption (VO₂) (mL/min, mL/kg/min, and % of predicted) was significantly higher on the treadmill (p < 0.01), as well the VO₂ at the ventilatory anaerobic threshold (VAT) and the peak oxygen pulse. A different kinetics of the oxygen pulse wave was observed in the same patient comparing the two testing modalities. Maximal respiratory-exchange-ratio values (>1.1) were reached more frequently on the cycle ergometer (p < 0.001). The minute ventilation–carbon dioxide output slope (VE/VCO₂ slope) was not different between the two tests (p = 0.400). Many parameters of CPET may differ depending on the ergometer used. These should be considered in clinical evaluation of Fontan patients and when exercise is to be prescribed. Full article

The oxygen blast furnace (OBF) is a promising technology for ironmaking, and its burden distribution pattern plays a key role in optimizing performance. This study investigates the impact of the peripheral opening extent (POE), which reflects the coke distribution adjacent to the furnace wall, on OBF performance using a computational fluid dynamics (CFD) process model. A 380 m³ OBF is simulated, incorporating reducing gas injection through both the hearth tuyeres and shaft tuyeres. By analyzing the inner states, the global performance is evaluated. The results show that the optimal POE value is 20°, which minimizes the fuel rate, maximizes productivity, and achieves the highest top gas utilization factor. As POE increases, chemical reaction carbon consumption decreases. The combustion heat in front of the tuyeres initially decreases and then increases, leading to a corresponding decrease and subsequent increase in carbon consumption in the tuyeres. The combined effects of these factors cause the fuel rate to first decrease and then increase. Additionally, this study quantifies the relationship between shaft injection rate and burden distribution. It is found that shaft injection improves the furnace’s thermal state and enhances the reducing atmosphere, leading to a reduced fuel rate. Notably, the optimal POE value remains constant at 20°, regardless of the shaft injection rate, suggesting that POE selection is independent of the injection rate. Overall, appropriate peripheral openings contribute to improving OBF global performance. These findings should be helpful to the industrial OBF operation. Full article

Male fertility has declined over the years, partly due to metabolic disorders such as obesity and Type 2 diabetes. Antidiabetic drugs, including GLP-1 receptor agonists like liraglutide, are widely used to manage these conditions and aid in weight loss. Within the male reproductive tract, Leydig cells (LCs) are essential since they produce testosterone. Notably, the influence of antidiabetics on LCs remains a subject of limited investigation. Herein, we aimed to evaluate the effect of liraglutide on the physiology of LCs. To this end, we cultured LCs (BLTK1 cell line) without (control) or in the presence of selected concentrations of liraglutide. We then assessed their metabolic viability, cell proliferation, LDH release, ROS production, mitochondrial membrane potential, and in vivo mitochondrial cell performance, as well as the number of mtDNA copies. We also measured androstenedione production. Our results showed that liraglutide at pharmacological and supra-pharmacological concentrations increased the metabolic viability of LCs and reduced ROS production at all concentrations. Furthermore, the pharmacological concentration of liraglutide increased the basal respiration, maximal respiration, proton leak, and oxygen consumption rate related to ATP-linked production. Androstenedione production remained unchanged, which may be related to the inherent limitations of the cell line in supporting steroidogenesis. Overall, our findings suggest that liraglutide exhibits a potential protective effect on LC function, particularly by enhancing metabolic viability, reducing oxidative stress, and improving mitochondrial performance, highlighting its potential beyond the established role in diabetes and weight management. Full article

The Polar Fitness Test (PFT) estimates maximal oxygen consumption ($\dot{\mathrm{V}}$O₂max) under resting conditions using heart rate data from the manufacturer’s wearable devices. We aimed to validate the PFT in a population with cardiovascular risk factors and to compare its results with five established equations predicting $\dot{\mathrm{V}}$O₂max based on the 6-min walk test (6MWT). Twenty-four participants (9 female; age 57.4 ± 10.2 years) undergoing medically supervised exercise training—including seven individuals on heart rate-limiting medication—completed the PFT, 6MWT, and cardiopulmonary exercise testing (CPET), which served as the criterion $\dot{\mathrm{V}}$O₂max measurement. The PFT showed a mean absolute percent-age error (MAPE) of 13.7%, an intraclass correlation coefficient (ICC) of 0.743, a mean bias of −1.0 mL/min/kg, and limits of agreement (LoA) of ±11.4 mL/min/kg compared to CPET. Among the 6MWT-based equations, only the Porcari equation demonstrated similar performance (MAPE 12.6%, ICC 0.725, mean bias 0.2 mL/min/kg, LoA ± 9.7 mL/min/kg), while other equations showed larger errors and systematic deviations. Our data indicate that the PFT may present an easily accessible option to estimate $\dot{\mathrm{V}}$O₂max on population level when exercise-based testing is not feasible. However, its variability limits use for individual clinical decisions, reaffirming the relevance of CPET for accurate assessment. Full article

Metabolic dysregulation in the heart plays a critical role in the pathogenesis of atrial fibrillation (AF), yet the underlying molecular mechanisms remain unclear. Loss-of-function variants in the zinc finger homeobox 3 gene (ZFHX3) increase AF risk by promoting structural and electrical remodeling. However, the role of ZFHX3 knockdown (KD) in cardiac metabolism has not been fully elucidated. This study investigated the impact of ZFHX3 KD on energy metabolism in atrial myocytes and assessed the therapeutic potential of trimetazidine (TMZ). Seahorse XFe24 extracellular flux analysis, bioluminescent assays, microplate enzyme activity assays, and Western blotting were used to study energy substrate (glucose and fatty acid) oxidation stress, intracellular lactate content, glucose uptake, pyruvate dehydrogenase (PDH) activity, and regulatory protein expression in control and ZFHX3 KD HL-1 cells with or without TMZ (10 μM) treatment. ZFHX3 KD cells exhibited a higher acute response in oxygen consumption after Etomoxir injection, upregulated CD36 and phosphorylated ACC expression, increased glucose uptake and lactate production, reduced PDH activity, and higher levels of PDK4 and LDHA. Furthermore, ZFHX3 KD cells showed mitochondrial Ca²⁺ overload and increased phosphorylated PDH and oxidized CaMKII proteins, all of which were significantly attenuated by TMZ. Additionally, TMZ improved mitochondrial dysfunction in ZFHX3 KD cells by decreasing basal and maximal respiration, spare capacity, and proton leak. These findings suggest that ZFHX3 downregulation shifts substrate preference toward fatty acid utilization at the expense of glucose oxidation, contributing to metabolic and mitochondrial calcium dysregulation. TMZ mitigates these effects, highlighting its therapeutic potential in AF associated with ZFHX3 deficiency. Full article

Trail running involves constant changes in terrain and slope, complicating the accurate assessment of energy expenditure during performance. This study aimed to examine the relationship between running power output (RPO), oxygen consumption (VO₂), carbon dioxide production (VCO₂), and energy expenditure per minute (EE_min) across positive and negative slopes in trained trail runners under standardized laboratory conditions. Fifteen male trail runners performed five randomized 5 min treadmill runs at 70% of VO₂ maximal speed on −7%, −5%, 0%, +5%, and +7% slopes. VO₂, VCO₂, EE_min, respiratory exchange ratio (RQ), heart rate (HR), and RPO were recorded. Statistical analysis included Shapiro–Wilk tests for normality, repeated-measures ANOVA to compare variables across slopes, and Spearman or Pearson correlations between RPO and physiological variables. Moderate to strong positive correlations were found between RPO and VO₂ (Rho = 0.80–0.84, p < 0.001) and between RPO and EE_min (Rho= 0.74–0.87, p < 0.01) across all conditions. These findings suggest that RPO measured via a wearable device may reflect changes in energy expenditure and supports the integration of wearable power metrics into training and nutritional strategies for trail running. However, further studies in female athletes, outdoor settings, extreme slopes, and altitude conditions are needed to confirm the generalizability of these results. Full article

Water scarcity in Jordan is intensifying, creating an urgent need for innovative approaches to maximize the use of nonconventional water resources, such as greywater treatment and reuse. This study presents a detailed analysis of the suitability of nature-based solutions (NbSs) for greywater treatment, with a focus on the application of horizontal flow constructed wetlands (HFCWs). Two systems were implemented to treat greywater generated from mosques located in Az-Zarqa Governorate, a dry region in Jordan. Following several months of operation, monitoring, and evaluation, the systems demonstrated high removal efficiencies: turbidity (>87%), total suspended solids (TSS) (>96%), chemical oxygen demand (COD) (>91%), and five-day biological oxygen demand (BOD₅) (>85%). The eight-square-meter HFCW units successfully produced one cubic meter of treated greywater per day, meeting Jordanian standards for reclaimed greywater (JS 1776:2013) for use in irrigating food crops, including those consumed raw. The system achieved a 70% reduction in water consumption compared to the same period in the year prior to its implementation. These results demonstrate the potential of constructed wetlands (CWs) as effective, low-cost, and sustainable NbSs for decentralized greywater treatment and reuse in water-scarce regions. Full article

Background: Cardiometabolic risk in adolescents represents a growing public health concern that is closely linked to modifiable factors such as physical fitness. Traditional statistical approaches often fail to capture complex, nonlinear relationships among anthropometric and fitness-related variables. Objective: To develop and evaluate supervised machine learning algorithms, including artificial neural networks and ensemble methods, for classifying cardiometabolic risk levels among Chilean adolescents based on standardized physical fitness assessments. Methods: A cross-sectional analysis was conducted using a large representative sample of school-aged adolescents. Field-based physical fitness tests, such as cardiorespiratory fitness (in terms of estimated maximal oxygen consumption [VO_2max]), muscular strength (push-ups), and explosive power (horizontal jump) testing, were used as input variables. A cardiometabolic risk index was derived using international criteria. Various supervised machine learning models were trained and compared regarding accuracy, F1 score, recall, and area under the receiver operating characteristic curve (AUC-ROC). Results: Among all the models tested, the gradient boosting classifier achieved the best overall performance, with an accuracy of 77.0%, an F1 score of 67.3%, and the highest AUC-ROC (0.601). These results indicate a strong balance between sensitivity and specificity in classifying adolescents at cardiometabolic risk. Horizontal jumps and push-ups emerged as the most influential predictive variables. Conclusions: Gradient boosting proved to be the most effective model for predicting cardiometabolic risk based on physical fitness data. This approach offers a practical, data-driven tool for early risk detection in adolescent populations and may support scalable screening efforts in educational and clinical settings. 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

Strength training has established itself as an essential component in physical conditioning programmes, not only to improve sports performance, but also for health purposes. To evaluate the effects of a strength training protocol with a predominance of the eccentric component on blood count, blood chemistry, and quadriceps muscle ultrasound in university students. 31 students (22.3 ± 4.14 years) of the professional programme in Sports of the Politécnico Colombiano Jaime Isaza Cadavid participated. A mesocycle was developed with three weekly sessions of eccentric training focused on the lower body and core zone. Pre and post-intervention measurements were taken anthropometry, haemogram, lipid profile, ultrasound of the right quadriceps, Bosco test, and Rockport test. The Wilcoxon signed-rank test was used, and the effect size was calculated using rank correlation. Statistically significant changes were observed in haematocrit, mean corpuscular volume, HDL, muscle thickness and echo-intensity, vertical jump power, and maximal oxygen consumption. A four-week eccentric strength training programme generates improvements in haematology, lipid profile, muscle quality assessed by ultrasound, and functional performance in university students. Full article

This study focuses on the design and optimization of a monopolar electrode configuration for the hybrid electrochemical treatment of real washing machine wastewater. A combined electrocoagulation (EC) and electro-oxidation (EO) system was optimized to maximize pollutant removal efficiency while minimizing energy consumption. The monopolar setup employed mixed metal oxide (MMO) and aluminum anodes, along with a stainless steel cathode, operating under controlled conditions with sodium chloride as the supporting electrolyte. An applied current density of 15 mA cm⁻² achieved 90% chemical oxygen demand (COD) removal, 98% surfactant degradation, complete turbidity reduction within 120 min, and pH stabilization near 8. Additionally, electrochemical disinfection achieved <2 MPN/100 mL, with no detectable phenols and the presence of organic anions such as oxalate and acetate. These results demonstrate the effectiveness of an optimized monopolar EC–EO system as a cost-efficient and sustainable strategy for wastewater treatment and potential water reuse. Further studies should focus on refining energy consumption and monitoring reaction by-products to enhance large-scale applicability. Full article

Background: ESC sports classification in 2020, based on cardiac morphological adaptations, may not fully reflect also the variations in functional parameters of athletes. This study aims to characterize CPET-derived physiological parameters in elite athletes according to the ESC classification and evaluate whether this morphological classification also corresponds to a functional categorization. Methods: Elite athletes underwent pre-participation screening before the 2023 European Games and 2024 Olympic Games. Athletes were classified into four categories (skill, power, mixed and endurance). CPET was performed on a cycle ergometer using a ramp protocol, with measurements of VO₂ max, heart rate, power output and ventilatory efficiency. Results: We enrolled 1033 athletes (46.8% females; mean 25.6 ± 5.2 years old) engaged in skill (14.1%), power (33.2%), mixed (33.3%) and endurance (19.4%) disciplines. O₂ pulse showed an incremental significant increase (p < 0.0001) among sport categories (skill 14.9 ± 3.8 mL/beat; power 17.5 ± 4.6 mL/beat, mixed 19 ± 4.3 mL/beat and endurance 22.7 ± 5.8 mL/beat). The lowest ${\dot{\mathrm{V}}\mathrm{O}}_2$max was observed in skill disciplines (36.3 ± 7.9 mL/min/kg) whilst endurance ones showed the highest values (52.4 ± 9.7 mL/min/kg) (p < 0.0001). ${\dot{\mathrm{V}}\mathrm{O}}_2$max was higher in power compared to mixed (42 ± 7.7 mL/min/kg vs. 40.5 ± 5.8 mL/min/kg, p = 0.005) disciplines with an overlapping amount between some mixed and power disciplines. No differences were found for VE max (p = 0.075). Conclusions: Our study provided values of CPET parameters in elite athletes. Significant differences in CPET parameters were observed among different sports disciplines, with endurance athletes showing the highest absolute and relative values in all parameters. An overlap amount was noted between mixed and power categories, especially for relative maximal oxygen consumption. Full article

Background: Super High-Intensity Continuous Training (SHCT) is a type of aerobic training program that combines high intensity with continuous loads, such as running for 20 min at 75%, 80%, or even 95% of the velocity at maximal oxygen uptake. Recent studies show significant positive effects, but the consequences of prolonged use remain unknown. Purpose: This study aims to investigate and evaluate the effects of prolonged application of the SHCT model in elite team handball players. Method: For this purpose, a field-based quasi-experiment was organized using the SHCT training model on 14 professional female team handball players competing in the first national league who participated in 16 weeks of SHCT training during the competition season. Results: After the application of SHCT training, the increases in the parameters of the aerobic profile (distance run in Cooper’s 12 min run test, maximum rate of oxygen consumption, value of the maximum relative oxygen consumption, running speed for which maximum rate of oxygen consumption occurs) reached from 25.4% to 35.2%. The effect size of these changes was η²p > 0.90 and was significant at the p < 0.001 level. Conclusions: The investigated aerobic model is effective. Therefore, its use is recommended for designing aerobic training for elite teams and the general sports population. Full article