Evidence of Left Ventricular Cardiac Remodeling After 6 Weeks of Sprint Interval Training.

Sprint interval training (SIT) leads to similar improvements in maximal oxygen uptake (V̇O) and maximal cardiac output as previously reported for traditional endurance training, but the exercise-induced effects on cardiac remodeling are still largely unknown. The aim of the current study was therefore to explore the effects of SIT on cardiac structure and function assessed by echocardiography in relation to, and controlling for, changes in both blood volume (BV) and heart rate (HR). Healthy men and women (n = 28) performed 6 weeks of SIT.

Non-Hospitalized Patients With Post-COVID Condition and Myopathic Electromyography Findings Show no Difference in Symptom Severity and Clinical Manifestations Compared to Those Without Myopathic Findings.

Introduction: The COVID-19 pandemic has resulted in a post-infectious syndrome designated as long-COVID or post-COVID condition (PCC) that presents with numerous symptoms including fatigue and myalgias. This study evaluated myopathic electromyography (EMG) findings in non-hospitalized PCC patients in relation to symptom severity, quality of life (QoL), and physical function.

Methods: Twenty-nine PCC patients with persistent symptoms ≥ 3 months after laboratory-confirmed SARS-CoV-2 infection, without hospitalization or comorbidities, were included.

Longitudinal changes in regional fat and muscle composition and cardiometabolic biomarkers over 5 years of hormone therapy in transgender individuals.

Background: Longitudinal studies investigating hormone therapy in transgender individuals are rare and often limited to 1- to 2-year follow-up periods.

Objectives And Methods: We examined changes in body composition, muscle volumes, and fat distribution as well as muscle strength, arterial stiffness, and cardiometabolic biomarkers in both transgender men (TM; n = 17, age 25 ± 5 years) and transgender women (TW; n = 16, age 28 ± 5 years) at baseline and after 1 and 5-6 years of hormone therapy in a longitudinal prospective cohort design. Whole-body and regional fat and muscle volumes were analyzed using magnetic resonance imaging, and blood samples were taken.

Aging Skeletal Muscles: What Are the Mechanisms of Age-Related Loss of Strength and Muscle Mass, and Can We Impede Its Development and Progression?

As we age, we lose muscle strength and power, a condition commonly referred to as sarcopenia (ICD-10-CM code (M62.84)). The prevalence of sarcopenia is about 5-10% of the elderly population, resulting in varying degrees of disability.

Cardiometabolic risk assessment in transgender individuals - differential impact of sex hormones and sex chromosomes.

Background: While transgender individuals represent a significant group seeking medical care, the differential effect of sex on cardiometabolic risk metrics is incompletely understood. Therefore, the current study aimed to characterize the impact of sex hormones and chromosomes on a contemporary panel of cardiometabolic risk biomarkers and functional cardiovascular measurements.

Methods: 17 transmen and 17 transwomen were studied at baseline (T0), 4 weeks (hormonal castration, T1), and 11 months following gender-affirming hormone treatment (T12).

Artificial neural network inference analysis identified novel genes and gene interactions associated with skeletal muscle aging.

Background: Sarcopenia is an age-related muscle disease that increases the risk of falls, disabilities, and death. It is associated with increased muscle protein degradation driven by molecular signalling pathways including Akt and FOXO1. This study aims to identify genes, gene interactions, and molecular pathways and processes associated with muscle aging and exercise in older adults that remained undiscovered until now leveraging on an artificial intelligence approach called artificial neural network inference (ANNi).

Functional Limitations and Exercise Intolerance in Patients With Post-COVID Condition: A Randomized Crossover Clinical Trial.

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.

Discordant gene expression in subcutaneous adipose and skeletal muscle tissues in response to exercise training.

Exercise has different effects on different tissues in the body, the sum of which may determine the response to exercise and the health benefits. In the present study, we aimed to investigate whether physical training regulates transcriptional network communites common to both skeletal muscle (SM) and subcutaneous adipose tissue (SAT). Eight such shared transcriptional communities were found in both tissues.

Gpcpd1-GPC metabolic pathway is dysfunctional in aging and its deficiency severely perturbs glucose metabolism.

Skeletal muscle plays a central role in the regulation of systemic metabolism during lifespan. With aging, this function is perturbed, initiating multiple chronic diseases. Our knowledge of mechanisms responsible for this decline is limited.

Predicting balance impairments in older adults: a wavelet-based center of pressure classification approach.

Background: Aging is associated with a decline in postural control and an increased risk of falls. The Center of Pressure (CoP) trajectory analysis is a commonly used method to assess balance. In this study, we proposed a new method to identify balance impairments in older adults by analyzing their CoP trajectory frequency components, sensory inputs, reaction time, motor functions, and Fall-related Concerns (FrC).

Optimal controllers resembling postural sway during upright stance.

The human postural control system can maintain our balance in an upright stance. A simplified control model that can mimic the mechanisms of this complex system and adapt to the changes due to aging and injuries is a significant problem that can be used in clinical applications. While the Intermittent Proportional Derivative (IPD) is commonly used as a postural sway model in the upright stance, it does not consider the predictability and adaptability behavior of the human postural control system and the physical limitations of the human musculoskeletal system.

Increased maximal oxygen uptake after sprint-interval training is mediated by central haemodynamic factors as determined by right heart catheterization.

There is a lack of knowledge regarding the contribution of central and peripheral factors to the increases in VO following sprint-interval training (SIT). This study investigated the importance of maximal cardiac output (Q ) in relation to VO improvements following SIT and the relative importance of the hypervolemic response on Q and VO . We also investigated whether systemic O extraction increased with SIT as has been previously suggested.

PCYT2-regulated lipid biosynthesis is critical to muscle health and ageing.

Muscle degeneration is the most prevalent cause for frailty and dependency in inherited diseases and ageing. Elucidation of pathophysiological mechanisms, as well as effective treatments for muscle diseases, represents an important goal in improving human health. Here, we show that the lipid synthesis enzyme phosphatidylethanolamine cytidyltransferase (PCYT2/ECT) is critical to muscle health.

Limited effect of over-the-counter doses of ibuprofen on mechanisms regulating muscle hypertrophy during resistance training in young adults.

We have previously shown that maximal over-the-counter doses of ibuprofen, compared with low doses of acetylsalicylic acid, reduce muscle hypertrophy in young individuals after 8 wk of resistance training. Because the mechanism behind this effect has not been fully elucidated, we here investigated skeletal muscle molecular responses and myofiber adaptations in response to acute and chronic resistance training with concomitant drug intake. Thirty-one young (aged 18-35 yr) healthy men ( = 17) and women ( = 14) were randomized to receive either ibuprofen (IBU; 1,200 mg daily; = 15) or acetylsalicylic acid (ASA; 75 mg daily; = 16) while undergoing 8 wk of knee extension training.

Transcriptomic profiling reveals sex-specific molecular signatures of adipose endothelial cells under obesogenic conditions.

Female mice display greater adipose angiogenesis and maintain healthier adipose tissue than do males upon high-fat diet feeding. Through transcriptome analysis of endothelial cells (EC) from the white adipose tissue of male and female mice high-fat-fed for 7 weeks, we found that adipose EC exhibited pronouncedly sex-distinct transcriptomes. Genes upregulated in female adipose EC were associated with proliferation, oxidative phosphorylation, and chromatin remodeling contrasting the dominant enrichment for genes related to inflammation and a senescence-associated secretory of male EC.

Skeletal muscle morphology, satellite cells, and oxidative profile in relation to physical function and lifelong endurance training in very old men.

In the current study, we compared muscle morphology in three advanced aging cohorts that differed in physical function, including a unique cohort of lifelong endurance athletes. Biopsies from the vastus lateralis muscle of seven lifelong endurance athletes (EAs) aged 82-92 yr, and 19 subjects from the Uppsala Longitudinal Study of Adult Men (ULSAM) aged 87-91 yr were analyzed. ULSAM subjects were divided into high- ( = 9, HF) and low- ( = 10, LF) function groups based on strength and physical function tests.

Single-cell sequencing deconvolutes cellular responses to exercise in human skeletal muscle.

Skeletal muscle adaptations to exercise have been associated with a range of health-related benefits, but cell type-specific adaptations within the muscle are incompletely understood. Here we use single-cell sequencing to determine the effects of exercise on cellular composition and cell type-specific processes in human skeletal muscle before and after intense exercise. Fifteen clusters originating from six different cell populations were identified.

MRI characterization of skeletal muscle size and fatty infiltration in long-term trained and untrained individuals.

This study investigated body composition measures in highly trained and untrained individuals using whole-body magnetic resonance imaging (MRI). Additionally, correlations between these measures and skeletal muscle gene expression were performed. Thirty-six individuals were included: endurance-trained males (ME, n = 8) and females (FE, n = 7), strength-trained males (MS, n = 7), and untrained control males (MC, n = 8) and females (FC, n = 6).

Sphingomyelinase activity promotes atrophy and attenuates force in human muscle fibres and is elevated in heart failure patients.

Background: Activation of sphingomyelinase (SMase) as a result of a general inflammatory response has been implicated as a mechanism underlying disease-related loss of skeletal muscle mass and function in several clinical conditions including heart failure. Here, for the first time, we characterize the effects of SMase activity on human muscle fibre contractile function and assess skeletal muscle SMase activity in heart failure patients.

Methods: The effects of SMase on force production and intracellular Ca handling were investigated in single intact human muscle fibres.

Assessment of anterior thigh muscle size and fat infiltration using single-slice CT imaging versus automated MRI analysis in adults.

Objectives: We examined the longitudinal and cross-sectional relationship between automated MRI-analysis and single-slice axial CT imaging for determining muscle size and muscle fat infiltration (MFI) of the anterior thigh.

Methods: Twenty-two patients completing sex-hormone treatment expected to result in muscle hypertrophy ( = 12) and atrophy ( = 10) underwent MRI scans using 2-point Dixon fat/water-separated sequences and CT scans using a system operating at 120 kV and a fixed flux of 100 mA. At baseline and 12 months after, automated volumetric MRI analysis of the anterior thigh was performed bilaterally, and fat-free muscle volume and MFI were computed.

Improvements in Maximal Oxygen Uptake After Sprint-Interval Training Coincide with Increases in Central Hemodynamic Factors.

Introduction: Sprint-interval training has been shown to improve maximal oxygen uptake, in part through peripheral muscle adaptations that increase oxygen utilization. In contrast, the adaptations of central hemodynamic factors in this context remain unexplored.

Purpose: The aim of the current study was to explore the effects of sprint-interval training on maximal oxygen uptake and central hemodynamic factors.

Functional improvements to 6 months of physical activity are not related to changes in size or density of multiple lower-extremity muscles in mobility-limited older individuals.

Older adults are encouraged to engage in multicomponent physical activity, which includes aerobic and muscle-strengthening activities. The current work is an extension of the Vitality, Independence, and Vigor in the Elderly 2 (VIVE2) study - a 6-month multicenter, randomized, placebo-controlled trial of physical activity and nutritional supplementation in community dwelling 70-year-old seniors. Here, we examined whether the magnitude of changes in muscle size and quality differed between major lower-extremity muscle groups and related these changes to functional outcomes.

Sarcopenia: What Is the Origin of This Aging-Induced Disorder?

We here review the loss of muscle function and mass (sarcopenia) in the framework of human healthspan and lifespan, and mechanisms involved in aging. The rapidly changing composition of the human population will impact the incidence and the prevalence of aging-induced disorders such as sarcopenia and, henceforth, efforts to narrow the gap between healthspan and lifespan should have top priority. There are substantial knowledge gaps in our understanding of aging.