Respiratory exchange ratio

We propose a novel method for assessing metabolic flexibility (MF) through indirect calorimetry. A total of twenty healthy volunteers (10 females; 10 males) aged 45-65 were categorized into a Low-Intensity activity group (LI, 0-1 session of 1 h per week) and a High-Intensity activity group (HI, 5-6 sessions of 2 h per week). Volunteers underwent a stepwise exercise test on a cycle ergometer, connected to a calorimeter, to examine respiratory gas exchange to evaluate peak fatty acid Oxidation (PFO) and peak carbohydrate oxidation (PCO)...

Palm cooling is a simple and easily implemented intervention strategy during exercise. We aimed to examine the effects of bilateral palm cooling before and during exercise on thermoregulatory-related and subjective indicators in a hot environment. Ten active men (age: 21 ± 1 years; height 172.2 ± 5.7 cm; weight 67.4 ± 7.2 kg) underwent three experimental trials at the same time of the day, consisting of palm cooling with 12°C (ICE12°C), palm cooling with 0°C (ICE0°C) where vasoconstriction is supposed to occur, and control (CON) trials...

The varied clinical presentations of SARS-CoV-2 infection have raised concerns about long-term consequences, especially "long-COVID" or "post-COVID-19 syndrome." In this context, the cardiorespiratory optimal point (COP) within the Cardiopulmonary Exercise Test (CPET) emerges as a crucial metric for evaluating functional capacities and detecting cardiovascular and pulmonary anomalies post-COVID-19. This study aimed to assess COP values among post-COVID-19 patients and categorized them based on the initial severity of their disease...

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Myoglobin (Mb) plays an important role at rest and during exercise as a reservoir of oxygen and has been suggested to regulate NO• bioavailability under hypoxic/acidic conditions. However, its ultimate role during exercise is still a subject of debate. We aimed to study the effect of Mb deficiency on maximal oxygen uptake ( <mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>max</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${\dot V_{{{\mathrm{O}}_2}\max }}$</mml:annotation></mml:semantics> </mml:math> ) and exercise performance in myoglobin knockout mice (Mb-/- ) when compared to control mice (Mb+/+ )...

BACKGROUND AND AIMS: Transient increases (overshoot) in respiratory gas analyses have been observed during exercise recovery, but their clinical significance is not clearly understood. An overshoot phenomenon of the respiratory exchange ratio (RER) is commonly observed during recovery from maximal cardiopulmonary exercise testing (CPET), but it has been found reduced in patients with heart failure with reduced ejection fraction (HFrEF). The aim of the study was to analyze the clinical significance of these RER recovery parameters and to understand if these may improve the risk stratification of patients with HFrEF...

BACKGROUND: Coronavirus disease 2019 (COVID-19) is the etiology of acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) is used to support gas exchange in patients who have failed conventional mechanical ventilation. However, there is no clear consensus on the timing of ECMO use in severe COVID-19 patients. OBJECTIVE: The aim of this study is to compare the differences in pre-ECMO time and ECMO duration between COVID-19 survivors and non-survivors and to explore the association between them...

OBJECTIVES: To conduct a systematic review and meta-analysis of evidence from randomized controlled trials (RCTs) comparing a short course of antibiotics (2-4 days), to a standard course (5-7 days), for the treatment of culture-negative neonatal sepsis. METHODS: Relevant databases were searched for RCTs comparing short- vs. standard-course of antibiotics for culture-negative sepsis. The primary outcomes were mortality and treatment failure, defined as the reappearance of clinical signs suggestive of sepsis within 7 days of stoppage of antibiotics...

BACKGROUND: Long COVID impacts ∼10% of people diagnosed with COVID-19, yet the pathophysiology driving ongoing symptoms is poorly understood. We hypothesised that 129 Xe magnetic resonance imaging (MRI) could identify unique pulmonary phenotypic subgroups of long COVID, therefore we evaluated ventilation and gas exchange measurements with cluster analysis to generate imaging-based phenotypes. METHODS: COVID-negative controls and participants who previously tested positive for COVID-19 underwent 129 XeMRI ∼14-months post-acute infection across three centres...

OBJECTIVES: Diabetes is an important global health problem. The occurrence and development of type 2 diabetes (T2D) involves multiple organs, among which the liver is an important organ. Artemether is a methyl ether derivative of artemisinin and has displayed significant antidiabetic effects. However, its regulation of glucose metabolism is not clearly elucidated. This study explored the effect of artemether on liver mitochondrial pyruvate metabolism. METHODS: T2D db/db mice were used and grouped into db/db and db/db+Art groups...

BACKGROUND & AIMS: Ketone supplementation is gaining popularity. Yet, its effects on exercise performance when muscle glycogen cannot be used remain to be determined. McArdle disease can provide insight into this question, as these patients are unable to obtain energy from muscle glycogen, presenting a severely impaired physical capacity. We therefore aimed to assess the effects of acute ketone supplementation in the absence of muscle glycogen utilization (McArdle disease). METHODS: In a randomized cross-over design, patients with an inherited block in muscle glycogen breakdown (i...

This study examined the effect of exogenous ketones (KB) on oxygen consumption (VO2 ), carbon dioxide production (VCO2 ), and glucose metabolism. The data were compared with the effects of endogenous ketonemia during both, a ketogenic diet or fasting. Eight healthy individuals (24.1 ±2.5 years, BMI 24.3 ±3.1 kg/m²) participated in a cross-over intervention study and were studied in a whole-room indirect calorimeter (WRIC) to assess macronutrient oxidation following four 24h-interventions: isocaloric controlled mixed diet (ISO), ISO supplemented with ketone salts (38...

INTRODUCTION: The use of dexamethasone (DXM) has been associated with decreased mortality in the patients with hypoxemia during the coronavirus disease-2019 (COVID-19) pandemic, while the outcomes with methylprednisolone (MTP) have been mixed. This real-life study aimed to evaluate the outcomes of patients with severe respiratory failure due to COVID-19 who were treated with high doses of MTP. MATERIALS AND METHODS: This retrospective cohort study enrolled hospitalised patients between May 2021 and August 2021, aged 18 years and above, with severe respiratory failure defined by a ratio of oxygen saturation to fraction of inspired oxygen (SF ratio) of less than 235...

OBJECTIVES: Exercise physiology is a branch of physiology that studies how physical activity and exercise alter the structure and function of living organisms. Knowledge of exercise physiology is crucial to improve athletic performance, improve people's ability to cope with extreme circumstances and approach chronic diseases. This research aimed to evaluate the knowledge of future healthcare professionals, namely, the medical students in Jordan regarding exercise physiology. METHODS: Responses were collected from 524 undergraduate medical students enrolled in clinical clerkship...

BACKGROUND: Multiple-breath washout (MBW) is an established technique to assess functional residual capacity (FRC) and ventilation inhomogeneity in the lung. Indirect calculation of nitrogen concentration requires accurate measurement of gas concentrations. AIM: To investigate the accuracy of the CO2 concentration and molar mass (MM) values used for the indirect calculation of nitrogen concentration in a commercial MBW device (EasyOne Pro LAB (EOPL), ndd Medizintechnik AG, Switzerland) and its impact on outcomes...

PURPOSE: To determine whether a 12-week supervised dose-graded aerobic exercise (D-GAE) training, when implemented in conjunction with traditional rehabilitation, could help pediatric survivors of acute lymphoblastic leukemia (ALL) enhance their cardiopulmonary capacity and improve their physical performance. METHODS: Fifty-eight pediatric survivors of ALL (age 13.78 ± 2.47 years; boys 60.34%) were assigned at random to either undergo the D-GAE in addition to the traditional physical rehabilitation (D-GAE group; n = 29) or the traditional physical rehabilitation solely (control group; n = 29)...

Prone positioning (PP) represents a therapeutic intervention with the proven capacity of ameliorating gas exchanges and ventilatory mechanics indicated in acute respiratory distress syndrome (ARDS). When PP is selectively applied to moderate-severe cases of ARDS, it sensitively affects clinical outcomes, including mortality. After the COVID-19 outbreak, clinical application of PP peaked worldwide and was applied in 60% of treated cases, according to large reports. Research on this topic has revealed many physiological underpinnings of PP, focusing on regional ventilation redistribution and the reduction of parenchymal stress and strain...

This study investigated the impact of resistance training with blood flow restriction during rest (BFRrest ) on the accuracy of estimated repetitions to failure (ERF). It also explored associations between error in ERF and mean concentric velocity (MCV) along with physiological responses. In a randomised cross-over study, 18 male trainers (23.4 ± 2.7 years) performed three sets of squats at 70% of their one-repetition maximum until failure. One session integrated BFRrest , while another employed traditional passive inter-set rest (TRAD) during the 3 min inter-set rest intervals...

OBJECTIVE: Drug exposure during pregnancy is frequent, even more during first trimester as pregnant women might not be aware of their condition. We used available electronic health records (EHRs) to describe the use of medications during the first trimester in pregnant women and to compare drug exposure between those women who had an abortion (either elective or spontaneous) compared to those who had live births. MATERIALS AND METHODS: Case-control study of abortions, either elective or spontaneous (cases), and live birth pregnancies (controls) in Sistema d'Informació per al Desenvolupament de la Investigació en Atenció Primària (Catalan Primary Health electronic health records) from 2012 to 2020...

BACKGROUND: This systematic review and meta-analysis aims to explore in heart failure (HF) patients with reduced ejection fraction (EF) undergoing exercise-based cardiac rehabilitation: 1) the comparison of temporal changes between peak oxygen uptake (VO2peak) and first ventilatory threshold (VO2VT1), 2) the association of VO2peak and VO2VT1 changes with physiological factors and 3) the differential effects of continuous aerobic exercise (CAE) and interval training (IT) on VO2peak and VO2VT1...