Search Results (74)

Background: Patients with prolonged mechanical ventilation (PMV) frequently require tracheostomy due to failure to wean, yet the pathway from ventilator dependence to successful decannulation remains complex and poorly standardised. Comprehensive respiratory rehabilitation is recognised as a core strategy for improving decannulation outcomes, but no unified, evidence-based guidelines currently exist for this population. This review addresses that gap by synthesising current evidence on respiratory rehabilitation and decannulation strategies for tracheostomized PMV patients. Methods: A narrative review was conducted through a systematic search of PubMed/MEDLINE covering publications indexed from May 2019 to February 2026, supplemented by targeted searches of Embase and the Cochrane Library. The search combined free-text keywords and Medical Subject Headings (MeSH) terms across eight search string combinations. Following title and abstract screening of 830 deduplicated records, 51 studies met eligibility criteria and were included in the final narrative synthesis. Results: Six core rehabilitation intervention domains were identified: respiratory muscle training, physical rehabilitation and nutritional optimisation, sedation and delirium management, speaking valve use, airway complication management, and ventilator mode optimisation. High-intensity inspiratory muscle training at no less than 50% of maximal inspiratory pressure is currently supported by the strongest available evidence among the interventions reviewed, although this threshold derives primarily from general ICU populations and has not been specifically validated in heterogeneous tracheostomized PMV cohorts. Decannulation readiness assessment may benefit from evaluating five core domains—neurological readiness, secretion management capacity (suctioning ≤ 4 times/24 h), cough efficacy (peak cough flow > 160 L/min), safe swallowing confirmed by instrumental assessment, and upper airway patency confirmed by fiberoptic bronchoscopy—using a structured multidisciplinary framework. Conclusions: Successful decannulation in tracheostomized PMV patients requires integration of evidence-based rehabilitation interventions, structured multidisciplinary assessment, and a patient-centred outcome framework that extends beyond physiological endpoints to encompass voice restoration, psychological well-being, and social reintegration. Significant evidence gaps remain—particularly for expiratory muscle training, population-specific decannulation protocols, and adapted rehabilitation models for resource-limited settings—representing priority areas for future research. Full article

Background: This study investigated the relationships among mitochondrial energy metabolism, immune function, and gut microbiota in mice under a fatigued state, providing preliminary evidence for future nutrition-related mechanistic and intervention studies. Methods: Mice were adaptively fed for 4 days and then randomly divided into a normal control group (NC) and a fatigue model group (NM). Immune organ indices, serum IgG levels, thigh muscle ATP content, mitochondrial respiratory chain complex I–IV activities, and gut microbiota composition were assessed using enzyme-linked immunosorbent assay (ELISA), microplate assays, and 16S rRNA gene sequencing. Results: Compared with the NC, the NM showed a significantly reduced spleen index, serum IgG levels, mitochondrial respiratory chain complex I, III, and IV activities, along with reduced ATP content. Regarding gut microbiota, mice in the NM exhibited disordered intestinal villus arrangement, inflammatory cell infiltration in the crypts and muscular layers, and markedly reduced intestinal microbial activity as well as protease and sucrase activities. 16S rRNA sequencing revealed fewer ASVs in the NM, with enrichment of Lactobacillaceae, Limosilactobacillus, and Ligilactobacillus, whereas the NC was characterized by Borkfalkiaceae and Borkfalkia. Linear discriminant analysis effect size (LEfSe) analysis identified Lactobacillaceae, Firmicutes_D, and Lactobacillales as characteristic taxa of the NM. Kyoto Encyclopedia of Genes and Genomes (KEGG) prediction indicated that fatigue-associated microbial functions were mainly related to carbohydrate, amino acid, and lipid metabolism. Correlation and RDA analyses further suggested that alterations in gut microbiota structure were closely associated with mitochondrial energy-related indicators and immune-related parameters. Conclusions: Fatigue was associated with alterations in energy metabolism, immune function, and gut microecology in mice. The “gut microbiota–energy metabolism–immunity” framework may represent a potential association-based framework and provides biological information to support future nutrition-related intervention studies. Full article

Pulmonary hypertension (PH) is a progressive, multifactorial syndrome characterized by elevated pulmonary arterial pressure and right heart dysfunction, associated with significant morbidity, impaired quality of life, and poor prognosis. Advances in classification, hemodynamic definitions, and targeted pharmacotherapies have improved understanding and management, yet therapeutic challenges persist across the five World Health Organization groups of PH. Historically, exercise was discouraged due to concerns about adverse hemodynamic effects, but growing evidence has suggested that structured, supervised training is safe and beneficial. Randomized trials and meta-analyses show improvements in six-minute walk distance, peak oxygen uptake, right ventricular function, ventilatory efficiency, and health-related quality of life, with a low incidence of adverse events. Physiological adaptations include favorable cardiac remodeling, enhanced endothelial function, improved skeletal and respiratory muscle performance, and improved neurohormonal activity. Despite this evidence, barriers such as patient fears, limited clinical expertise, and restricted access to specialized rehabilitation programs hinder widespread implementation. Current guidelines recommend supervised exercise as part of pulmonary rehabilitation for patients with stable PH, supporting its role as an adjunct to pharmacotherapy. This descriptive review briefly summarizes the pathophysiology of PH, phenotype-related differences and current therapeutic approaches, and the beneficial adaptations to exercise training, with the aim of informing exercise specialists and supporting safer, more effective integration of exercise-based rehabilitation into patient care. Full article

The horse represents one of the most physiologically specialized athletic mammals, capable of sustaining both high-intensity and prolonged exercise. Central to this remarkable performance capacity is the metabolic adaptability of skeletal muscle and its mitochondrial network. This narrative review synthesizes current evidence from equine, human, and rodent studies on exercise-induced mitochondrial remodeling in equine skeletal muscle. A comprehensive literature search was conducted across PubMed, Web of Science, and Scopus using terms related to equine exercise physiology, mitochondrial biology, and skeletal muscle metabolism. Preference was given to peer-reviewed original research and review articles. Mitochondria regulate oxidative phosphorylation, substrate oxidation, redox signaling, and cellular responses to metabolic stress induced by exercise. Training induces extensive mitochondrial adaptations, including mitochondrial biogenesis, remodeling of the respiratory chain, enhanced oxidative phosphorylation efficiency, and increased metabolic flexibility. These adaptations are believed to contribute to improvements in aerobic capacity, delayed fatigue onset, and enhanced recovery following exercise, although direct mechanistic evidence in horses remains limited. In equine skeletal muscle, mitochondrial plasticity is closely linked to muscle fiber composition and the distribution of oxidative and glycolytic fibers. Exercise-induced signaling pathways involving AMP-activated protein kinase (AMPK), Ca²⁺-dependent kinases, and the transcriptional coactivator PGC-1α regulate mitochondrial biogenesis and metabolic remodeling. In addition, mitochondrial dynamics, including fusion, fission, and mitophagy, maintain mitochondrial quality and functional efficiency during repeated training stimuli. Experimental studies in Thoroughbred and Standardbred horses demonstrate that training has been associated with increases in mitochondrial density and respiratory capacity in equine skeletal muscle, contributing directly to improved aerobic performance and metabolic efficiency. However, mitochondrial adaptations must be interpreted within the broader context of musculoskeletal adaptation, as metabolic improvements may occur faster than structural adaptation of tendons and ligaments. This review synthesizes current knowledge on exercise-induced mitochondrial remodeling in equine skeletal muscle, while highlighting the limited mechanistic evidence available in horses and the need for more standardized longitudinal studies. Full article

Reptiles with diving capabilities have evolved physiological adaptations as well as conformational changes to temporarily sustain life underwater. Despite the importance of both respiratory and cardiovascular systems during diving, most studies have focused on respiratory adaptations. Thus, characterisation of previously undescribed cardiovascular anatomical variations in diving vertebrates is of broad interest. Thirteen clinically healthy, free-ranging adult female Murray River turtles (Chelidae: Emydura macquarii) were collected for research purposes, euthanised and autopsied. Prominent, valve-like structures, comprised exclusively of smooth muscle myocytes, were identified in medium- and large-calibre muscular arteries of all individuals. Additionally, multiple intramural vascular channels, mimicking post-thrombotic recanalization, were observed within medium-calibre muscular arteries. Further, we confirmed the presence of alpha-smooth-muscle actin-positive cells lining the cardiac atria in E. macquarii. Quantitative morphometric analyses demonstrated that the valve-like structures frequently occupied a substantial proportion of the vascular lumen, in some cases exceeding 90% luminal narrowing. Their consistent presence across multiple individuals and organ systems supports the interpretation that these are physiological vascular structures rather than artefacts. This study examines the potential physiological and evolutionary roles of these vascular structures, providing a basis for further research into cardiovascular adaptations in vertebrates subjected to postural changes and diving-related haemodynamic challenges. Full article

Background: Respiratory muscle strength (RMS) is a critical factor influencing athletic performance, particularly in high-intensity or prolonged activities. RMS encompasses inspiratory (IMs) and expiratory muscles (EMs), which differ in anatomical structure, fiber composition, and responsiveness to training. Methods: This pilot interventional within-subject study investigated the effects of two resistive respiratory muscle training (RMT) protocols on RMS and small airway function in eight physically active adults (two females, six males). Maximal inspiratory (MIP) and expiratory pressures (MEP), along with pulmonary function tests (PFTs), were measured using the Airofit PRO™ device and spirometry before and after two consecutive 7-day training protocols, with a 2-day break between interventions. The workload was progressively increased by lengthening the duration of forced inhalation and exhalation, while keeping the air resistance constant. Results: Results demonstrated significant improvements in MEP across both protocols and after a 10-day washout period (p < 0.001–0.03), whereas MIP showed no significant changes (p = 0.19–0.66). Moderate transient improvements were observed in small airway flow (MEF25%) following the first protocol (ES = 0.62), which regressed after the second. Conclusions: These outcomes suggest differential responsiveness of respiratory muscles to RMT; EMs, characterized by a higher proportion of fast-twitch type II fibers and a predominantly passive role in normal breathing, respond rapidly to short-duration, high-intensity forced expiration training through neuromuscular adaptations. Conversely, IMs, dominated by slow-twitch type I fibers, require longer-duration, higher-load training to elicit meaningful adaptations, explaining the limited changes in MIP. Small airway function appeared minimally trainable due to structural and physiological constraints, with short-term improvements likely reflecting effort-dependent factors rather than lasting adaptations. Finally, RMT can selectively enhance EM performance through appropriately designed short-duration, high-intensity interventions, while IMs may necessitate prolonged or higher-load stimuli. The findings highlight the importance of targeted training strategies, individualized to muscle fiber composition and functional demands, to optimize respiratory performance. Future research should investigate longer interventions, larger diverse cohorts, and precise measurement methods to further elucidate RMT’s effects on both respiratory muscles and small airway function. Full article

Backgrounds: The aim of this pilot study was to evaluate the hierarchical contribution of individual genetic polymorphisms to the variability of autonomic regulation parameters and respiratory function in athletes of different sport specializations using Classification and Regression Tree (CRT) analysis. Methods: The study included athletes divided into two groups: hockey players (n = 48) and martial artists (n = 43). Heart rate variability (LF, HF) parameters and spirometric indices (FEV₁) were assessed. Genetic analysis included 8 single nucleotide polymorphisms (SNPs): IL6 rs1800795, VDR rs731236, KCNJ11 rs5219, ADRB2 rs1042713, ADRB2 rs1042714, TRHR rs16892496, MSTN rs1805086, UCP3 rs1800849. Results: In martial artists, the main predictors were genes responsible for adrenoreceptor sensitivity (ADRB2) and neuroimmune interactions (IL6). In hockey players, the most significant predictors were genes involved in muscle growth (MSTN), energy metabolism (UCP3), and neuroendocrine regulation (TRHR). These findings indicate that similar resting HRV parameters in athletes from different sports may be associated with different genetic polymorphisms, reflecting sport-specific physiological adaptations to training loads. Conclusions: The results highlight the sport-specific nature of genetic determinants of autonomic regulation. In martial artists, genes related to the immuno-adrenergic axis (IL6, ADRB2) appear to play a dominant role, whereas in hockey players neuroendocrine, muscle-metabolic, and mitochondrial factors (TRHR, MSTN, UCP3) demonstrate greater influence. The observed interactions between genotypes and FEV₁ emphasize the importance of transitioning from generalized approaches toward personalized monitoring strategies in sports science. Full article

Background: Regular aerobic exercise during childhood promotes critical physiological adaptations in the cardiovascular and respiratory system. Finswimming, a unique aquatic sport, requires high-intensity demands and specific breathing patterns. The present study aimed to compare respiratory function and cardiorespiratory responses between young male finswimmers and sedentary age-matched non-athletes. Methods: Thirty-two boys aged 8 to 12 years old were stratified into the finswimmers group (FSG, n = 16) and the non-athletes group (NAG, n = 16). Assessments included pulmonary function (spirometry) and respiratory muscle strength (Maximum Inspiratory Pressure, MIP/Maximum Expiratory Pressure, MEP). Exercise capacity was evaluated using the modified shuttle walk test (MSWT). Results: The FSG exhibited significantly higher pulmonary function (Forced Vital Capacity, Forced Expiratory Volume in 1 s, Maximum Voluntary Ventilation; p < 0.05) and superior MIP compared to the NAG (105.3 ± 24.8 versus 87.3 ± 24.7 cmH₂O; p = 0.022). During the MSWT, FSG covered substantially greater distances (746.6 ± 97.2 versus 591.1 ± 86.4 m; p < 0.001) with lower levels of leg fatigue (Borg 0–10) (0.53 ± 0.39 versus 2.13 ± 1.93; p = 0.004) and demonstrated lower heart rate recovery time (4.47 ± 0.68 versus 5.75 ± 0.68 min; p < 0.001) compared to NAG. At the iso-level (8th level of MSWT), FSG scored lower levels of leg fatigue (0.13 ± 0.12 versus 2.02 ± 2.0; p = 0.001) compared to NAG, indicating better peripheral oxygen % saturation (100 ± 0.0 versus 98.14 ± 1.16; p < 0.001). Conclusions: Systematic exercise training enhances profound cardiorespiratory and peripheral muscle adaptations in children. Enhanced cardiorespiratory function allows young athletes to achieve higher workloads and recover faster than sedentary peers, highlighting the sport’s role in establishing a robust cardiorespiratory fitness. Full article

Background and Objectives: The hypertrophic adaptation of the diaphragm to inspiratory muscle training (IMT) remains insufficiently characterized, particularly in healthy and athletic populations. To address this gap, we conducted a meta-analysis and meta-regression to evaluate the effects of IMT on diaphragm thickness and identify potential moderating factors. Materials and Methods: A systematic search was conducted across PubMed, MEDLINE, Embase, CINAHL, and SPORTDiscus as well as Google Scholar (gray literature) through November 2025. Eight studies involving 203 healthy participants met the inclusion criteria. A random-effects model was used to calculate pooled effect sizes and meta-regression estimates. Results: IMT produced a statistically significant moderate increase in diaphragm muscle thickness, with a standardized mean difference (SMD) of Hedges’ g = 0.52 (95% CI: 0.19 to 0.85; p < 0.05). Subgroup analyses indicated that IMT with 50% maximal inspiratory pressure (MIP) produces a statistically significant effect (p = 0.0069), whereas fitness status and age did not significantly influence outcomes (p = 0.589 and p = 0.126, respectively). Meta-regression analyses revealed that only baseline MIP value (β = 0.030; 95% CI: 0.009 to 0.050; p = 0.004) was associated with diaphragm hypertrophy. Conclusions: IMT with 50% of MIP elicits meaningful diaphragmatic hypertrophy in healthy individuals. This response appears independent of fitness status or age, but is significantly influenced by baseline inspiratory muscle strength (MIP). These findings support the utility of IMT in enhancing respiratory muscle morphology in health and performance contexts. Full article

Background and Objectives: Cross-country skiing requires high levels of upper-body strength and efficient respiratory function to sustain performance during sport-specific movements. This study aimed to examine the effects of an eight-week ski ergometer-based training program on upper-extremity isokinetic muscle strength and pulmonary function in competitive cross-country skiers. Materials and Methods: A total of 20 cross-country skiers voluntarily participated in the study (experimental group: n = 10, control group: n = 10). The research was conducted using a quasi-experimental controlled design. During the eight-week training period, the experimental group performed ski ergometer training three times per week at an intensity of 80–90% of maximal heart rate, with a target distance of 2.5 km per session, in addition to their regular training program. Measurements were obtained before and after the intervention. Results: Following the ski ergometer training period, significant increases were observed in FVC (F = 18.565, p < 0.001, ηp² = 0.508) and FEV₁ (F = 8.789, p = 0.008, ηp² = 0.328), which were associated with enhanced respiratory muscle endurance and ventilatory capacity. Regarding the isokinetic strength parameters, the DPPE60 variable showed significant main effects of time (F = 33.770, p < 0.001, ηp² = 0.652) and time × group interaction (F = 18.590, p < 0.001, ηp² = 0.508), indicating higher upper-extremity strength values across the measurement period. Additionally, strong positive correlations were found between dominant and nondominant limbs (r = 0.79–0.92; p < 0.05), indicating balanced bilateral strength development and high neuromuscular coordination. Conclusions: Ski ergometer-based training was associated with improvements in upper-extremity peak power (DPPE60) and ventilatory capacity (FVC) beyond general training-related adaptations. These findings suggest that SkiErg training may be a useful complementary method for enhancing selected performance-related physiological parameters in cross-country skiers. Full article

Duchenne muscular dystrophy (DMD) causes progressive skeletal, respiratory and cardiac muscle weakness in affected males. Most DMD patients develop scoliosis following loss of ambulation. This narrative review describes recommendations for the management of scoliosis in DMD patients using a review of the current literature evidence and a consensus review by the DMD Care UK Spinal Surgery Working Group. Advances in medical treatments have improved life expectancy for DMD patients. Spinal bracing is not effective in preventing the deterioration of scoliosis. Seating and wheelchair adaptations can provide postural support. The multidisciplinary assessment of patients with DMD requiring treatment for scoliosis is reviewed, with particular focus on bone, cardiac and respiratory health. The indications, surgical techniques, and type of spinal instrumentation for surgical management for progressively severe scoliosis with or without pelvic obliquity are discussed. Anaesthetic techniques, intraoperative neuromonitoring, perioperative care, and postoperative management in the ICU are discussed for the optimal management of DMD patients undergoing surgery to correct spinal deformity. Finally, regional and holistic functional assessments, patient satisfaction and long-term health, quality of life, and life expectancy for DMD patients undergoing treatment for spinal deformity are reviewed. Full article

Microproteins are small polypeptides translated from short open reading frames (sORFs) that typically encode < 100 amino acids. Advances in ribosome profiling, mass spectrometry, and computational prediction have revealed a growing number of microproteins that play important roles in cellular metabolism, organelle function, and stress adaptation; however, these were considered non-coding or functionally insignificant. At the mitochondrial level, microproteins, such as MTLN (also known as mitoregulin/MOXI) and BRAWNIN, contribute to lipid oxidation, oxidative phosphorylation efficiency, and respiratory chain assembly. Other microproteins at the endoplasmic reticulum–mitochondria interface, including PIGBOS and several muscle-resident regulators of calcium cycling, show diverse biological contexts in which these microproteins act. A subset of microproteins responds to nutrient availability. For example, SMIM26 modulates mitochondrial complex I translation under serine limitation, and non-coding RNA expressed in mesoderm-inducing cells encoded with peptides facilitates glucose uptake during differentiation, indicating that some microproteins can affect metabolic adaptation through localized translational- or organelle-level mechanisms. Rather than functioning as primary nutrient sensors, these microproteins complement classical nutrient-responsive pathways such as AMP-activated protein kinase-, peroxisome proliferator-activated receptor-, and carbohydrate response element binding protein-mediated signaling. As the catalog of microproteins continues to expand, integrating proteogenomics, nutrient biology, and functional studies will be central to defining their physiological relevance; these integrative approaches will also help reveal their potential applications in metabolic health. Full article

Enterovirus D68 (EV-D68) is a significant global pathogen associated with severe respiratory infections and acute flaccid myelitis in children. Currently, there are no vaccines or antiviral drugs available for EV-D68, and a robust model to elucidate the pathogenesis of EV-D68 and evaluate treatment methods is lacking. We developed a mouse-adapted EV-D68 strain that caused progressive limb paralysis after intramuscular inoculation in 7-day-old mice. Viral load analysis showed that the skeletal muscle and spinal cord had the highest titers and most severe injuries. RNA sequencing of the infected muscle, brain, spinal cord, and lung tissues revealed differentially expressed genes (DEGs) associated with viral infection and pathogenesis. DEGs were significantly enriched in various pathways associated with antiviral immunity, interferon responses, and cytokine signaling. In the spinal cord, DEGs highlighted mitochondrial dysfunction and oxidative stress as crucial contributors to neural damage. Flow cytometry analysis of spinal cord cells showed that EV-D68 activates the immune system, leading to systemic inflammation and significant increases in CD8⁺ and CD4⁺ T cells, but limited neutrophil and monocyte infiltration. This mouse model provides a valuable tool for studying EV-D68 pathogenesis and evaluating antiviral and vaccine efficacy, thereby advancing the understanding of its neuropathological mechanisms. Importance: We developed a novel mouse model of EV-D68 that provides a valuable tool for studying its pathogenesis and evaluating antiviral and vaccine efficacy, deepening the understanding of its neuropathological basis. Full article

Skeletal muscle dysfunction is a major systemic manifestation of COPD that shapes symptoms, exercise tolerance and mortality. Current evidence can be integrated within a Damage–Regeneration–Remodeling framework linking mechanics and biology to clinical phenotypes. Pulmonary hyperinflation and chest wall geometry chronically load the diaphragm and other respiratory muscles in COPD, whereas inactivity and exacerbation-related disuse underload locomotor muscles. Across muscle compartments, oxidative/nitrosative stress, activation of proteolytic pathways, mitochondrial and endoplasmic reticulum stress, microvascular limitations, neuromuscular junction instability, and myosteatosis degrade muscle quality. The diaphragm adapts with a fast-to-slow fiber shift, greater oxidative capacity, and sarcomere foreshortening, improving endurance, whereas limb muscles show atrophy, a glycolytic shift, reduced oxidative enzymes, extracellular matrix accrual, and fat infiltration. Translational levers that address these mechanisms include: (I) Reduce damage: bronchodilation, lung-volume reduction, oxygen, non-invasive ventilation, early mobilization, pulmonary rehabilitation, neuromuscular stimulation, and corticosteroid stewardship; (II) Enable regeneration: progressive resistance plus high-intensity/heavy-load endurance training; adequate protein and vitamin-D intake, and endocrine correction; and (III) Steer remodeling: increase physical activity (with/without coaching/telecoaching), functional assessment and CT or MRI monitoring, inspiratory-muscle training, and phenotype-guided adjuncts in selected cases. This framework clarifies why lung deflation strategies benefit inspiratory mechanics, whereas limb recovery requires behavioral and metabolic interventions layered onto systemic optimization. Full article

Exercise activates many metabolic and signaling pathways in skeletal muscle and other tissues and cells, causing numerous systemic beneficial metabolic effects. Traditionally recognized for their principal role in oxygen (O₂) transport, erythrocytes have emerged as dynamic regulators of vascular homeostasis. Beyond their respiratory function, erythrocytes modulate vascular tone through crosstalk with other cells and tissues, particularly under hypoxia and physical exercise. This regulatory capacity is primarily mediated through the controlled release in the bloodstream of adenosine triphosphate (ATP) and nitric oxide (NO), two potent vasodilators that contribute significantly to matching oxygen supply with tissue metabolic demand. Emerging evidence suggests that many other erythrocyte-released molecules may act as additional factors involved in tissue-erythrocyte crosstalk. This review highlights erythrocytes as active contributors to exercise-induced adaptations through their exocrine signaling. Full article