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Respiratory exchange ratio

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https://www.readbyqxmd.com/read/28090142/the-midpoint-between-ventilatory-thresholds-approaches-maximal-lactate-steady-state-intensity-in-amateur-cyclists
#1
A B Peinado, Dm Pessôa Filho, V Díaz, P J Benito, M Álvarez-Sánchez, A G Zapico, F J Calderón
The aim was to determine whether the midpoint between ventilatory thresholds (MPVT) corresponds to maximal lactate steady state (MLSS). Twelve amateur cyclists (21.0 ± 2.6 years old; 72.2 ± 9.0 kg; 179.8 ± 7.5 cm) performed an incremental test (25 W·min(-1)) until exhaustion and several constant load tests of 30 minutes to determine MLSS, on different occasions. Using MLSS determination as the reference method, the agreement with five other parameters (MPVT; first and second ventilatory thresholds: VT1 and VT2; respiratory exchange ratio equal to 1: RER = 1...
December 2016: Biology of Sport
https://www.readbyqxmd.com/read/28075500/very-short-short-term-benefit-of-inpatient-outpatient-cardiac-rehabilitation-programs-after-coronary-artery-bypass-grafting-surgery
#2
Dejan Spiroski, Mojsije Andjić, Olivera Ilić Stojanović, Milica Lazović, Ana Djordjević Dikić, Miodrag Ostojić, Branko Beleslin, Snežana Kostić, Marija Zdravković, Dragan Lović
BACKGROUND: Exercise-based rehabilitation is an important part of treatment patients following coronary artery bypass graft (CABG) surgery. HYPOTHESIS: To evaluate effect of very short/short-term exercise training on cardiopulmonary exercise testing (CPET) parameters. METHODS: We studied 54 consecutive patients with myocardial infarction (MI) treated with CABG surgery referred for rehabilitation. The study population consisted of 50 men and 4 women (age 57...
January 11, 2017: Clinical Cardiology
https://www.readbyqxmd.com/read/28065839/cardiovascular-function-in-long-term-hematopoietic-cell-transplantation-survivors
#3
Saro H Armenian, David Horak, Jessica M Scott, George Mills, Aida Siyahian, Jennifer Berano Teh, Pamela S Douglas, Stephen J Forman, Smita Bhatia, Lee W Jones
Peak oxygen consumption (VO2peak), as measured by cardiopulmonary exercise testing (CPET), is a powerful independent predictor of cardiovascular disease (CVD) and all-cause mortality in a broad range of populations. We assessed the safety and feasibility of CPET in aging long-term HCT survivors, a population at high risk for premature-onset of CVD. Next we examined how organ-specific impairments (e.g. cardiac, pulmonary, hematologic) impact VO2peak after HCT. Twenty consecutive HCT survivors underwent a comprehensive assessment of cardiopulmonary health that included CPET, echocardiography with strain, pulmonary function testing, six-minute walk test, and timed-up and go...
January 5, 2017: Biology of Blood and Marrow Transplantation
https://www.readbyqxmd.com/read/28053881/effect-of-novel-dietary-supplement-on-metabolism-in%C3%A2-vitro-and-in%C3%A2-vivo
#4
Roger A Vaughan, Ailish C White, Jason R Beam, Nicholas P Gannon, Randi Garcia-Smith, Roy M Salgado, Marco Bisoffi, Kristina A Trujillo, Carole A Conn, Christine M Mermier
Obesity is an increasingly prevalent and preventable morbidity with multiple behavioral, surgical and pharmacological interventions currently available. Commercial dietary supplements are often advertised to stimulate metabolism and cause rapid weight and/or fat loss, although few well-controlled studies have demonstrated such effects. We describe a commercially available dietary supplement (purportedly containing caffeine, catechins, and other metabolic stimulators) on resting metabolic rate in humans, and on metabolism, mitochondrial content, and related gene expression in vitro...
January 2017: Journal of Traditional and Complementary Medicine
https://www.readbyqxmd.com/read/28050930/the-effects-of-crushed-ice-ingestion-prior-to-steady-state-exercise-in-the-heat
#5
Matthew Zimmermann, Grant Landers, Karen E Wallman, Jacinta Saldaris
This study examined the physiological effects of crushed ice ingestion prior to steady state exercise in the heat. Ten healthy males with age (23±3 y), height (176.9±8.7 cm), body-mass (73.5±8.0 kg), V̇O2peak (48.5±3.6 mL·kg·min(-1)) participated in the study. Participants completed 60 min of cycling at 55% of their V̇O2peak preceded by 30 min of pre-cooling whereby 7 g·kg(-1) of thermoneutral water (CON) or crushed ice (ICE) was ingested. The reduction in Tc at the conclusion of pre-cooling was greater in ICE (-0...
January 4, 2017: International Journal of Sport Nutrition and Exercise Metabolism
https://www.readbyqxmd.com/read/28035015/case-studies-in-physiology-maximal-oxygen-consumption-and-performance-in-a-centenarian-cyclist
#6
Veronique Louise Billat, Gilles Dhonneur, Laurence Mille-Hamard, Laurence Le Moyec, Iman Momken, Thierry Launay, Jean-Pierre Koralsztein, Sophie Besse
: The purpose of this study was to examine the physiological characteristics of an elite centenarian cyclist who, at 101 years old, established the one-hour cycling record for individuals ≥ 100 years old (24.25 km) and to determine the physiological factors associated with his performance improvement two years later at 103 years old (26.92 km; +11%). Before each record, he performed an incremental test on a cycling ergometer. For two years, he trained 5,000 km a year with a polarized training that involved cycling 80% of mileage at "light" RPE ≤ 12 and 20% at "hard" RPE ≥ 15 at a cadence between 50 and 70 rpm...
December 29, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28035013/alterations-to-mitochondrial-fatty-acid-use-in-skeletal-muscle-after-chronic-exposure-to-hypoxia-depend-on-metabolic-phenotype
#7
Alexandra Malgoyre, Clovis Chabert, Julia Tonini, Nathalie Koulmann, Xavier Bigard, Hervé Sanchez
We investigated the effects of chronic hypoxia on the maximal use of and sensitivity of mitochondrial to different substrates in rat slow-oxidative (soleus, SOL) and fast-glycolytic (extensor digitorum longus, EDL) muscles. We studied mitochondrial respiration in situ in permeabilized myofibers, using pyruvate, octanoate, palmitoyl-carnitine (PC) or palmitoyl-coenzyme A (PCoA). The hypophagia induced by hypoxia may also alter metabolism. We therefore used a group of pair-fed rats (reproducing the same caloric restriction as observed in hypoxic animals) in addition to the normoxic control fed ad libitum...
December 29, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28028317/oral-leptin-supplementation-throughout-lactation-in-rats-prevents-later-metabolic-alterations-caused-by-gestational-calorie-restriction
#8
N Szostaczuk, T Priego, M Palou, A Palou, C Picó
OBJECTIVES: Calorie-restriction during gestation in rats has been seen to produce lasting detrimental effects in the offspring, affecting energy balance control and other related metabolic functions. Our aim was to assess whether leptin supplementation throughout lactation may prevent the dysmetabolic phenotype in adulthood associated with gestational calorie restriction. METHODS: Three groups of male Wistar rats were followed: the offspring of ad libitum fed dams (controls); the offspring of 20% calorie-restricted dams during gestation (CR); and CR rats supplemented with physiological doses of leptin throughout lactation (CR-Leptin)...
December 28, 2016: International Journal of Obesity: Journal of the International Association for the Study of Obesity
https://www.readbyqxmd.com/read/28028037/muscle-interleukin-6-and-fasting-induced-pdh-regulation-in-mouse-skeletal-muscle
#9
Anders Gudiksen, Lærke Bertholdt, Mikkel Birkkjær Vingborg, Henriette Watson Hansen, Stine Ringholm Ringholm, Henriette Pilegaard
Fasting prompts a metabolic shift in substrate utilization from carbohydrate to predominant fat oxidation in skeletal muscle and pyruvate dehydrogenase (PDH) is seen as a controlling link between the competitive oxidation of carbohydrate and fat during metabolic challenges like fasting. Interleukin (IL)-6 has been proposed to be released from muscle with concomitant effects on both glucose and fat utilization. The aim was to test the hypothesis that IL-6 has a regulatory impact on fasting-induced suppression of skeletal muscle PDH...
December 27, 2016: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28025868/metabolic-responses-to-exercise-on-land-and-in-water-following-glucose-ingestion
#10
Kazumichi Kurobe, Ayaka Kousaka, Futoshi Ogita, Naoyuki Matsumoto
Although aerobic exercise after a meal decreases postprandial blood glucose, the differences in glucose response between land and aquatic exercise are unclear. Thus, we examined the effect of different modes of exercise with same energy expenditure following glucose ingestion on carbohydrate metabolism. Ten healthy sedentary men (age, 22 ± 1 years) participated in this study. All subjects performed each of three exercise modes (cycling, walking and aquatic exercise) for 30 min after ingestion of a 75-g glucose solution with 1-2 weeks between trials...
December 26, 2016: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28012036/no-influence-of-ischemic-preconditioning-on-running-economy
#11
Gungeet Kaur, Megan Binger, Claire Evans, Tiffany Trachte, Gary P Van Guilder
PURPOSE: Many of the potential performance-enhancing properties of ischemic preconditioning suggest that the oxygen cost for a given endurance exercise workload will be reduced, thereby improving the economy of locomotion. The aim of this study was to identify whether ischemic preconditioning improves exercise economy in recreational runners. METHODS: A randomized sham-controlled crossover study was employed in which 18 adults (age 27 ± 7 years; BMI 24.6 ± 3 kg/m(2)) completed two, incremental submaximal (65-85% VO2max) treadmill running protocols (3 × 5 min stages from 7...
December 23, 2016: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28003557/comparing-the-effects-of-two-different-levels-of-hyperoxygenation-on-gas-exchange-during-open-endotracheal-suctioning-a-randomized-crossover-study
#12
Jacqueline Rodrigues de Freitas Vianna, Valéria Amorim Pires Di Lorenzo, Miléa Mara Lourenço da Silva Simões, Maurício Jamami
BACKGROUND: Endotracheal suctioning is required for mechanically ventilated patients to maintain a patent airway. Studies show that open endotracheal suctioning affects respiratory mechanics and gas exchange. The aim of this study was to compare the effectiveness of hyperoxygenation with FIO2 + 0.20 above baseline and hyperoxygenation with FIO2 1.0 in preventing hypoxemia, and to determine the impact of open endotracheal suctioning on the pulmonary ventilation of critical subjects receiving mechanical ventilatory support...
January 2017: Respiratory Care
https://www.readbyqxmd.com/read/27997805/physiologic-effects-of-high-flow-nasal-cannula-in-acute-hypoxemic-respiratory-failure
#13
Tommaso Mauri, Cecilia Turrini, Nilde Eronia, Giacomo Grasselli, Carlo Alberto Volta, Giacomo Bellani, Antonio Pesenti
RATIONALE: High-flow nasal cannula (HFNC) improves the clinical outcomes of non-intubated acute hypoxemic respiratory failure (AHRF) patients. OBJECTIVES: To assess the effects of HFNC on gas exchange, inspiratory effort, minute ventilation, end-expiratory lung volume, dynamic compliance and ventilation homogeneity in AHRF patients. METHODS: This was a prospective randomized cross-over study in non-intubated AHRF patients with PaO2/setFiO2 ≤300 mmHg admitted to the Intensive Care Unit...
December 20, 2016: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/27996337/steady-state-energy-balance-in-animal-models-of-obesity-and-weight-loss
#14
Magnus Kringstad Olsen, Helene Johannessen, Nikki Cassie, Perry Barrett, Koji Takeuchi, Bård Kulseng, Duan Chen, Chun-Mei Zhao
OBJECTIVE: We wanted to exam the steady-state energy balance by using high-fat diet-induced obese (DIO) rats and mice as models for positive energy balance, and gastric bypassed (GB) rats and gene knockout of muscarinic acetylcholine M3 receptor (M3KO) mice as models for negative energy balance. METHODS: One hundred and thirty-two rats and mice were used. Energy balance was measured by a comprehensive laboratory animal monitoring system. Gene expression was analysed by in situ hybridisation in M3KO mice...
December 20, 2016: Scandinavian Journal of Gastroenterology
https://www.readbyqxmd.com/read/27938891/reference-standards-for-cardiorespiratory-fitness-measured-with-cardiopulmonary-exercise-testing-using-cycle-ergometry-data-from-the-fitness-registry-and-the-importance-of-exercise-national-database-friend-registry
#15
Leonard A Kaminsky, Mary T Imboden, Ross Arena, Jonathan Myers
The importance of cardiorespiratory fitness (CRF) is well established. This report provides newly developed standards for CRF reference values derived from cardiopulmonary exercise testing (CPX) using cycle ergometry in the United States. Ten laboratories in the United States experienced in CPX administration with established quality control procedures contributed to the "Fitness Registry and the Importance of Exercise: A National Database" (FRIEND) Registry from April 2014 through May 2016. Data from 4494 maximal (respiratory exchange ratio, ≥1...
December 7, 2016: Mayo Clinic Proceedings
https://www.readbyqxmd.com/read/27916643/homeostatic-effects-of-exercise-and-sleep-on-metabolic-processes-in-mice-with-an-overexpressed-skeletal-muscle-clock
#16
Allison J Brager, Lydia Heemstra, Raman Bhambra, J Christopher Ehlen, Karyn A Esser, Ketema N Paul, Colleen M Novak
Brain and muscle-ARNT-like factor (Bmal1/BMAL1) is an essential transcriptional/translational factor of circadian clocks. Loss of function of Bmal1/BMAL1 is highly disruptive to physiological and behavioral processes. In light of these previous findings, we examined if transgenic overexpression of Bmal1/BMAL1 in skeletal muscle could alter metabolic processes. First, we characterized in vivo and ex vivo metabolic phenotypes of muscle overexpressed mice (male and female) compared to wild-type littermates (WT)...
January 2017: Biochimie
https://www.readbyqxmd.com/read/27914920/can-lowering-the-guidance-force-of-robot-assisted-gait-training-induce-a-sufficient-metabolic-demand-in-subacute-dependent-ambulatory-stroke-patients
#17
So Young Lee, Eun Young Han, Bo Ryun Kim, Min Ho Chun, Yong Ki Lee
OBJECTIVE: To assess the effects of guidance force (GF) and gait speed (GS) on cardiorespiratory responses and energy cost in subacute dependent ambulatory stroke patients. DESIGN: Cross sectional study. SETTING: University rehabilitation hospital. PARTICIPANTS: Ten subacute stroke patients (mean age: 64.50±19.20), who were dependent ambulators (functional ambulation category [FAC] ≤2). INTERVENTIONS: Patients participated in cardiorespiratory tests during robot-assisted gait training...
November 30, 2016: Archives of Physical Medicine and Rehabilitation
https://www.readbyqxmd.com/read/27913834/key-role-of-pacing-site-as-determinant-factor-of-exercise-testing-performance-in-pediatric-patients-with-chronic-ventricular-pacing
#18
Michel Cabrera Ortega, Hiram Tápanes Duamy, Dunia B Benítez Ramos
Chronic right ventricular (RV) apical pacing has been associated with deterioration of functional capacity and chronotropic incompetence during exercise testing in children. The effects of alternative pacing site on exercise performance in pediatric population remain unknown. We evaluated the influence of ventricular pacing site on exercise capacity in pediatric patients with complete congenital atrioventricular block requiring permanent pacemaker therapy. Sixty-four children paced from RV apex (n = 26), RV midseptum (n = 15) and left ventricular (LV) apex (n = 23) were studied cross-sectionally...
December 2, 2016: Pediatric Cardiology
https://www.readbyqxmd.com/read/27886210/physical-activity-energy-expenditure-and-defense-of-body-weight-in-melanocortin-4-receptor-deficient-male-rats
#19
Tariq I Almundarij, Mark E Smyers, Addison Spriggs, Lydia A Heemstra, Lisa Beltz, Eric Dyne, Caitlyn Ridenour, Colleen M Novak
Melanocortin 4 receptor (MC4R) variants contribute to human obesity, and rats lacking functional MC4R (Mc4r(K314X/K314X)) are obese. We investigated the hypothesis that low energy expenditure (EE) and physical activity contribute to this obese phenotype in male rats, and determined whether lack of functional MC4R conferred protection from weight loss during 50% calorie restriction. Though Mc4r(K314X/K314X) rats showed low brown adipose Ucp1 expression and were less physically active than rats heterozygous for the mutation (Mc4r(+/K314X)) or wild-type (Mc4r(+/+)) rats, we found no evidence of lowered EE in Mc4r(K314X/K314X) rats once body weight was taken into account using covariance...
November 25, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27879383/high-flow-nasal-cannula-in-critically-ill-subjects-with-or-at-risk-for-respiratory-failure-a-systematic-review-and-meta-analysis
#20
REVIEW
Wagner Luis Nedel, Caroline Deutschendorf, Edison Moraes Rodrigues Filho
High-flow nasal cannula (HFNC) oxygen delivery has been gaining attention as an alternative means of respiratory support for critically ill patients, with recent studies suggesting equivalent outcomes when compared with other forms of oxygen therapy delivery. The main objective of this review was to extract current data about the efficacy of HFNC in critically ill subjects with or at risk for respiratory failure. We performed a systematic review of publications (from database inception to October 2015) that evaluated HFNC in critically ill subjects with or at risk for acute respiratory failure and performed a meta-analysis comparing HFNC with noninvasive ventilation (NIV) and with standard oxygen therapy regarding major outcomes: incidence of invasive mechanical ventilation and ICU mortality...
January 2017: Respiratory Care
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