A mathematical model based on oxygen flow was developed to study the effects of pulmonary to systemic flow ratios (QP/QS) on systemic oxygen availability. The model suggests that QP/QS = 1 is the safest ratio that would provide the largest safety margin in either low cardiac output or low pulmonary oxygenation conditions. The optimal value of QP/QS that will result in maximum oxygen availability is smaller than unity and depends on several circulatory parameters such as cardiac output, maximal oxygen capacity, level of pulmonary oxygenation, and oxygen consumption. The values of these parameters also dictate the permissible range of QP/QS beyond which abrupt oxygen deficiency ensues. Decreased pulmonary resistance resulting in increased pulmonary flow may eventually result in QP/QS that is beyond the vital range.
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Front Physiol
December 2024
Department of Sport and Exercise Science, Paris Lodron University Salzburg, Salzburg, Austria.
Introduction: Our recent meta-analyses have demonstrated that high-intensity interval training (HIIT) causes a range of mean changes in various measures and predictors of endurance and sprint performance in athletes. Here, we extend the analyses to relationships between mean changes of these measures and consider implications for understanding and improving HIIT that were not apparent in the previous analyses.
Methods: The data were mean changes from HIIT with highly trained endurance and elite other (mainly team sport) athletes in studies where two or more measures or predictors of performance were available.
Over the past two decades, rapid advancements in magnetic resonance technology have significantly enhanced the imaging resolution of functional Magnetic Resonance Imaging (fMRI), far surpassing its initial capabilities. Beyond mapping brain functional architecture at unprecedented scales, high-spatial-resolution acquisitions have also inspired and enabled several novel analytical strategies that can potentially improve the sensitivity and neuronal specificity of fMRI. With small voxels, one can sample from different levels of the vascular hierarchy within the cerebral cortex and resolve the temporal progression of hemodynamic changes from parenchymal to pial vessels.
View Article and Find Full Text PDFCommun Biol
January 2025
Georgia Cancer Center, Augusta University, Augusta, GA, 30912, USA.
The transsulfuration (TSS) pathway is an alternative source of cysteine for glutathione synthesis. Little of the TSS pathway in antioxidant capacity in sickle cell disease (SCD) is known. Here, we evaluate the effects of TSS pathway activation through cystathionine beta-synthase (CBS) to attenuate reactive oxygen species (ROS) and ferroptosis stresses in SCD.
View Article and Find Full Text PDFExp Physiol
January 2025
Université Clermont Auvergne, Clermont-Ferrand, France.
This systematic review summarizes the available evidence on respiratory muscle endurance training involving voluntary isocapnic hyperpnoea among patients with chronic diseases. It includes both randomized and non-randomized controlled trials implementing this exercise training modality performed either alone or in combination with other interventions. It was conducted using the following databases: PubMed, Google Scholar, Physiotherapy Evidence Database (PEDro), Embase, CINAHL, CENTRAL, Cochrane and ReeDOC.
View Article and Find Full Text PDFFront Pharmacol
December 2024
Department of Respiratory Medicine, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China.
Pulmonary diseases are a major category of diseases that pose a threat to human health. The most common drugs currently used to treat lung diseases are still chemical drugs, but this may lead to drug resistance and damage to healthy organs in the body. Therefore, developing new drugs is an urgent task.
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