Exercise intolerance

BACKGROUND: Between 2020 and 2022, eight calves in a Nebraska herd (composite Simmental, Red Angus, Gelbvieh) displayed exercise intolerance during forced activity. In some cases, the calves collapsed and did not recover. Available sire pedigrees contained a paternal ancestor within 2-4 generations in all affected calves. Pedigrees of the calves' dams were unavailable, however, the cows were ranch-raised and retained from prior breeding seasons, where bulls used for breeding occasionally had a common ancestor...

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has introduced the medical community to the phenomenon of long COVID, a condition characterized by persistent symptoms following the resolution of the acute phase of infection. Among the myriad of symptoms reported by long COVID sufferers, chronic fatigue, cognitive disturbances, and exercise intolerance are predominant, suggesting systemic alterations beyond the initial viral pathology. Emerging evidence has pointed to mitochondrial dysfunction as a potential underpinning mechanism contributing to the persistence and diversity of long COVID symptoms...

BACKGROUND: Pediatric post coronavirus disease 2019 (COVID-19) condition (PPCC) is a heterogeneous syndrome, which can significantly affect the daily lives of children. This study aimed to identify clinically meaningful phenotypes in children with PPCC, to better characterize and treat this condition. METHODS: Participants were children with physician-diagnosed PPCC, referred to the academic hospital Amsterdam UMC in the Netherlands between November 2021 and March 2023...

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GDF15 (growth differentiation factor 15) is a marker of cellular energetic stress linked to physical-mental illness, aging, and mortality. However, questions remain about its dynamic properties and measurability in human biofluids other than blood. Here, we examine the natural dynamics and psychobiological regulation of plasma and saliva GDF15 in four human studies representing 4,749 samples from 188 individuals. We show that GDF15 protein is detectable in saliva (8% of plasma concentration), likely produced by salivary glands secretory duct cells...

BACKGROUND: Patients suffering from long COVID may exhibit autonomic dysregulation. However, the association between autonomic dysregulation and exercise intolerance and the impact of therapeutic interventions on its modulation remain unclear. This study investigated the relationship between heart rate recovery at the first minute (HRR1), a proxy for autonomic imbalance, and exercise intolerance in patients with long COVID. Additionally, the study aimed to assess the effects of a 12-week home-based inspiratory muscle training program on autonomic modulation in this patient population...

AIMS: The study aims to investigate exercise-limiting factors in hypertrophic cardiomyopathy (HCM) using combined stress echocardiography and cardiopulmonary exercise test. METHODS AND RESULTS: A symptom-limited ramp bicycle exercise test was performed in the semi-supine position on a tilting dedicated ergometer. Echocardiographic images were obtained concurrently with gas exchange measurements along predefined stages of exercise. Oxygen extraction was calculated using the Fick equation at each activity level...

PURPOSE: Childhood cancer survivors are at risk for cardiac dysfunction and impaired physical performance, though underlying cellular mechanisms are not well studied. In this cross-sectional study, we examined the association between peripheral blood mitochondrial DNA copy number (mtDNA-CN, a proxy for mitochondrial function) and markers of performance impairment and cardiac dysfunction. METHODS: Whole-genome sequencing, validated by quantitative polymerase chain reaction, was used to estimate mtDNA-CN in 1720 adult survivors of childhood cancer (48...

BACKGROUND: Tracheobronchomalacia (TBM) is characterized by excessive dynamic airway collapse. Severe TBM can be associated with substantial morbidity. Children with secondary TBM associated with esophageal atresia/tracheoesophageal fistula (EA/TEF) and vascular-related airway compression (VRAC) demonstrate clinical improvement following airway pexy surgery. It is unclear if children with severe primary TBM, without secondary etiologies (EA/TEF, vascular ring, intrinsic pulmonary pathology, or complex cardiac disease) demonstrate clinical improvement following airway pexy surgery...

Aims This study aims to retrospectively quantify skeletal muscle mass from cardiovascular imaging studies in total cavopulmonary connection (TCPC) patients and to correlate calculated muscle mass with clinical outcomes. Materials and methods Ninety-one TCPC patients at a mean age of 24.0 ±5.5 years (37 women; 40.7%) who underwent chest computed tomography (CT) or cardiac magnetic resonance imaging (MRI) as part of their follow-up were identified in a single-center database. The cross-sectional skeletal muscle index (SMI) at the Th4 and Th12 levels was calculated from CT images, and the dorsal skeletal muscle area (SMA) at the Th12 level was measured from an MRI...

Metamorphosis is a transition from growth to reproduction, through which an animal adopts adult behavior and metabolism. Yet the neural mechanisms underlying the switch is unclear. Here we report that neuronal E93, a transcription factor essential for metamorphosis, regulates the adult metabolism, physiology, and behavior in Drosophila melanogaster. Identified from a screen designed to find new neuronal regulators of metabolism, E93 is required to control appetite, metabolism, exercise endurance, and circadian rhythms...

BACKGROUND: Health-related quality of life (HRQoL) assessments such as St. George's Respiratory Questionnaire (SGRQ) are often used as outcome measures to evaluate patient-perceived changes in health status among individuals with lung disease. Several factors have been linked to deterioration in SGRQ, including symptoms (dyspnea, wheezing) and exercise intolerance. Whether these findings apply to individuals with alpha-1 antitrypsin deficiency (AATD) remains incompletely studied. This longitudinal study examines the trajectory of SGRQ scores in a cohort of United States individuals with AATD-associated lung disease and defines factors associated with longitudinal change...

BACKGROUND: Exercise intolerance is a common symptom associated with atrial fibrillation (AF). However, echocardiographic markers that can predict impaired exercise capacity are lacking. OBJECTIVE: To investigate the association between echocardiographic parameters and exercise capacity assessed via cardiopulmonary exercise testing (CPET) in patients with AF. METHODS: This single-center prospective study enrolled patients with AF who underwent echocardiography and CPET to evaluate exercise capacity at a tertiary center for AF management from 2020 to 2022...

Pulmonary hypertension (PH) is a chronic, progressive condition in which respiratory muscle dysfunction is a primary contributor to exercise intolerance and dyspnea in patients. Contractile function, blood flow distribution, and the hyperemic response are altered in the diaphragm with PH, and we sought to determine whether this may be attributed, in part, to impaired vasoreactivity of the resistance vasculature. We hypothesized that there would be blunted endothelium-dependent vasodilation and impaired myogenic responsiveness in arterioles from the diaphragm of PH rats...

Four years post-pandemic, SARS-CoV-2 continues to affect many lives across the globe. An estimated 65 million people suffer from long COVID, a term used to encapsulate the post-acute sequelae of SARS-CoV-2 infections that affect multiple organ systems. Known symptoms include chronic fatigue syndrome, brain fog, cardiovascular issues, autoimmunity, dysautonomia, and clotting due to inflammation. Herein, we review long COVID symptoms, the proposed theories behind the pathology, diagnostics, treatments, and the clinical trials underway to explore treatments for viral persistence, autonomic and cognitive dysfunctions, sleep disturbances, fatigue, and exercise intolerance...

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible fibrotic disease whose natural history is characterised by a progressive worsening of the pulmonary function, exertional dyspnoea, exercise intolerance, reduced physical activity, and health-related quality of life (HRQOL) impairment. Pulmonary rehabilitation (PR) is a comprehensive, multi-disciplinary programme that uses a combination of strength training, teaching, counselling, and behaviour modification techniques to reduce symptoms and optimise functional capacity in patients with chronic lung disease...

Glycogen Storage Disease (GSD) IXd, caused by PHKA1 gene mutations, is an X-linked rare disorder that can be asymptomatic or associated with exercise intolerance. GSD type II is an autosomal recessive disorder caused by mutations in the GAA gene that lead to severe cardiac and skeletal muscle myopathy. We report the first case of co-occurrence of type IXd and type II GSDs in a 53-year-old man with an atypical glycogen storage disease presentation consisting in myalgia in the lower limbs at both rest and after exercise and increased levels of transaminases from the age of 16...

Genetic variations in the glucocorticoid receptor (GR) gene NR3C1 can impact metabolism. The single nucleotide polymorphism (SNP) rs6190 (p.R23K) has been associated in humans with enhanced metabolic health, but the SNP mechanism of action remains completely unknown. We generated a transgenic knock-in mice genocopying this polymorphism to elucidate how the mutant GR impacts metabolism. Compared to non-mutant littermates, mutant mice showed increased muscle insulin sensitivity and strength on regular chow and high-fat diet, blunting the diet-induced adverse effects on weight gain and exercise intolerance...

IMPORTANCE: Many patients with post-COVID condition (PCC) experience persistent fatigue, muscle pain, and cognitive problems that worsen after exertion (referred to as postexertional malaise). Recommendations currently advise against exercise in this population to prevent symptom worsening; however, prolonged inactivity is associated with risk of long-term health deterioration. OBJECTIVE: To assess postexertional symptoms in patients with PCC after exercise compared with control participants and to comprehensively investigate the physiologic mechanisms underlying PCC...

We present the case of a young male patient (height, 158.1 cm [+3.3 standard deviation (SD)]; weight, 63.7 kg [body mass index, 25.5]) with diabetes mellitus and severe insulin resistance associated with a heterozygous pathogenic insulin receptor substrate 1 ( IRS1 ) frameshift mutation. The patient also had severe acanthosis nigricans. Notably, the patient's father was undergoing treatment with high doses of insulin for diabetes mellitus, and had been experiencing angina pectoris. Laboratory data showed a fasting plasma glucose level of 88 mg/dL, hemoglobin A1C (HbA1c) of 7...