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Ventilatory threshold

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https://www.readbyqxmd.com/read/28435685/quantification-and-physiological-significance-of-the-rightward-shift-of-the-v-slope-during-incremental-cardiopulmonary-exercise-testing
#1
Hirotaka Nishijima, Kazuo Kondo, Kazuya Yonezawa, Hiroki Hashimoto, Masayuki Sakurai
BACKGROUND: Ventilatory anaerobic threshold (VAT) is frequently used as a measure of exercise tolerance, with the V-slope method being the standard; however, this needs to be visually determined. Over the years, we have observed that the V-slope itself often appears to shift rightward before the appearance of the VAT (RtShift: rightward shift of V-slope). This phenomenon has long been known to occur during the first 1-2 min of steady-state exercise and disappears thereafter; it is attributed to CO2 storage, presumably in active muscle...
2017: BMC Sports Science, Medicine and Rehabilitation
https://www.readbyqxmd.com/read/28399379/physiology-of-arousal-in-osa-and-potential-impacts-for-sedative-treatment
#2
Amy S Jordan, Fergal J O'Donoghue, Jennifer M Cori, John Trinder
Treatment options for patients with obstructive sleep apnea (OSA) intolerant of continuous positive airway pressure (CPAP) are limited. Thus, new therapies are sought. Recently, there has been interest in using sedatives to delay arousal from sleep, allowing upper airway dilator muscle recruitment sufficient to re-open the airway while maintaining sleep. In this review the rationale for sedative use and prior sedative studies in OSA are presented, along with a description of six factors that may determine sedative treatment success...
April 11, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28389695/effects-of-low-temperature-on-breathing-pattern-and-ventilatory-responses-during-hibernation-in-the-golden-mantled-ground-squirrel
#3
Cheryl L Webb, William K Milsom
During entrance into hibernation in golden-mantled ground squirrels (Callospermophilus lateralis), ventilation decreases as metabolic rate and body temperature fall. Two patterns of respiration occur during deep hibernation. At 7 °C body temperature (T b ), a breathing pattern characterized by episodes of multiple breaths (20.6 ± 1.9 breaths/episode) separated by long apneas or nonventilatory periods (T nvp ) (mean = 11.1 ± 1.2 min) occurs, while at 4 °C T b , a pattern in which breaths are evenly distributed and separated by a relatively short T nvp (0...
April 7, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28389601/anterior-cerebral-blood-velocity-and-end-tidal-co2-responses-to-exercise-differ-in-children-and-adults
#4
Lindsay A Ellis, Philip N Ainslie, Victoria A Armstrong, Laura Emily Morris, Ryan Gerard Simair, Nathan R Sletten, Christine M Tallon, Ali Mary McManus
Little is known about the response of the cerebrovasculature to acute exercise in children and how these responses might differ with adults. Therefore, we compared changes in middle cerebral artery blood velocity (MCAVmean), partial pressure of end-tidal carbon dioxide (PETCO2), blood pressure and ventilation (VE) in response to incremental exercise between children and adults. Thirteen children [aged 9±1 (SD) y] and 13 sex-matched adults [aged 25±4 y] completed a maximal exercise test during which MCAVmean, PETCO2 and VE were measured continuously...
April 7, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28388274/six-minute-stepper-test-to-set-pulmonary-rehabilitation-intensity-in-patients-with-copd-a-retrospective-study
#5
Tristan Bonnevie, Francis-Edouard Gravier, Marie Leboullenger, Clément Médrinal, Catherine Viacroze, Antoine Cuvelier, Jean-François Muir, Catherine Tardif, David Debeaumont
Pulmonary rehabilitation (PR) improves outcomes in patients with chronic obstructive pulmonary disease (COPD). Optimal assessment includes cardiopulmonary exercise testing (CPET), but consultations are limited. Field tests could be used to individualize PR instead of CPET. The six-minute stepper test (6MST) is easy to set up and its sensitivity and reproducibility have previously been reported in patients with COPD. The aim of this study was to develop a prediction equation to set intensity in patients attending PR, based on the 6MST...
April 7, 2017: COPD
https://www.readbyqxmd.com/read/28386984/ventilatory-and-behavioural-responses-of-the-marbled-sole-pseudopleuronectes-yokohamae-to-progressive-hypoxia
#6
H Nishizawa, Y Kono, N Arai, J Shoji, H Mitamura
This study identified ventilatory and behavioural responses in the marbled sole Pseudopleuronectes yokohamae under experimentally induced progressive decreases in dissolved oxygen (DO) levels. Ventilation frequency showed an increase with decreasing DO levels from normoxia to 2·75 mg O2  l(-1) , followed by a decrease in ventilation frequency at decreased DO levels from 2·00 to 0·75 mg O2 l(-1) . At DO levels below 2·00 mg l(-1) , behaviours at the bottom were suppressed, whereas avoidance behaviours increased...
April 7, 2017: Journal of Fish Biology
https://www.readbyqxmd.com/read/28384329/oxygen-uptake-efficiency-slope-as-a-useful-measure-of-cardiorespiratory-fitness-in-morbidly-obese-women
#7
Tatiana Onofre, Nicole Oliver, Renata Carlos, Amanda Felismino, Renata Cristina Corte, Eliane Silva, Selma Bruno
Cardiopulmonary assessment through oxygen uptake efficiency slope (OUES) data has shown encouraging results, revealing that we can obtain important clinical information about functional status. Until now, the use of OUES has not been established as a measure of cardiorespiratory capacity in an obese adult population, only in cardiac and pulmonary diseases or pediatric patients. The aim of this study was to characterize submaximal and maximal levels of OUES in a sample of morbidly obese women and analyze its relationship with traditional measures of cardiorespiratory fitness, anthropometry and pulmonary function...
2017: PloS One
https://www.readbyqxmd.com/read/28382813/oxygen-uptake-and-body-composition-after-aquatic-physical-training-in-women-with-fibromyalgia-a-randomized-controlled-trial
#8
Carolina P Andrade, Antonio R Zamunér, Meire Forti, Thalita F França, Nayara Y Tamburús, Ester Silva
BACKGROUND: Aquatic physical training (APT) has been strongly recommended to improve symptoms in fibromyalgia syndrome (FMS). However, its effects on body composition and whether lean body mass (LBM) directly influences the aerobic functional capacity of this population are still not clear. AIM: To investigate whether APT can help improve body composition and increase the aerobic functional capacity in women with FMS, and whether oxygen consumption (VO2) related to LBM can better quantify the functional capacity of this population...
April 4, 2017: European Journal of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/28382529/a-comparison-of-methods-for-determining-the-ventilatory-threshold-implications-for-surgical-risk-stratification
#9
Baruch Vainshelboim, Shravan Rao, Khin Chan, Ricardo M Lima, Euan A Ashley, Jonathan Myers
PURPOSE: The ventilatory threshold (VT) is an objective physiological marker of the capacity of aerobic endurance that has good prognostic applications in preoperative settings. Nevertheless, determining the VT can be challenging due to physiological and methodological issues, especially in evaluating surgical risk. The purpose of the current study was to compare different methods of determining VT and to highlight the implications for assessing perioperative risk. METHODS: Our study entailed analysis of 445 treadmill cardiopulmonary exercise tests from 140 presurgical candidates with an aortic abdominal aneurysm (≥3...
April 5, 2017: Canadian Journal of Anaesthesia, Journal Canadien D'anesthésie
https://www.readbyqxmd.com/read/28379019/-irregular-breathing-during-the-cardiopulmonary-exercise-test-from-mildly-irregular-breathing-pattern-to-periodic-breathing-of-oscillatory-ventilation-type
#10
František Várnay, Leona Mífková, Pavel Homolka, Petr Dobšák
The fluctuating course of tidal volume (VT), breathing frequency (DF) and minute ventilation (VE) during the cardio-pulmonary exercise test using a ramp incremental protocol occurs not only in patients, but relatively frequently also in healthy individuals. It can account for a number of irregularities in the course of the curves VO2, VCO2 and in particular of those of ventilatory equivalents for O2 and CO2 (EQO2, EQCO2) as well as curves of partial pressure of end-tidal oxygen and partial pressure of end-tidal carbon dioxide (PETO2, PETCO2), which are also used, inter alia, to establish ventilatory thresholds...
2017: Vnitr̆ní Lékar̆ství
https://www.readbyqxmd.com/read/28375677/cardiopulmonary-exercise-testing-in-adult-congenital-heart-disease
#11
Valentina Mantegazza, Anna Apostolo, Alfred Hager
Recently, the number of patients with congenital heart diseases reaching adulthood has been progressively increasing in developed countries and new issues are emerging regarding them: the evaluation of their capacity to cope with physical activity, and whether this knowledge can be used to optimize medical management. A symptom-limited cardiopulmonary exercise test has proven to be an essential tool because it can objectively evaluate the functional cardiovascular capacity of these patients, identify the pathological mechanisms of the defect (circulatory failure, shunts, pulmonary hypertension) and help prescribe an individualized rehabilitation program when needed...
April 4, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28373412/ventriculo-arterial-coupling-detects-occult-rv-dysfunction-in-chronic-thromboembolic-pulmonary-vascular-disease
#12
Richard G Axell, Simon J Messer, Paul A White, Colm McCabe, Andrew Priest, Thaleia Statopoulou, Maja Drozdzynska, Jamie Viscasillas, Elizabeth C Hinchy, James Hampton-Till, Hatim I Alibhai, Nicholas Morrell, Joanna Pepke-Zaba, Stephen R Large, Stephen P Hoole
Chronic thromboembolic disease (CTED) is suboptimally defined by a mean pulmonary artery pressure (mPAP) <25 mmHg at rest in patients that remain symptomatic from chronic pulmonary artery thrombi. To improve identification of right ventricular (RV) pathology in patients with thromboembolic obstruction, we hypothesized that the RV ventriculo-arterial (Ees/Ea) coupling ratio at maximal stroke work (Ees/Eamax sw) derived from an animal model of pulmonary obstruction may be used to identify occult RV dysfunction (low Ees/Ea) or residual RV energetic reserve (high Ees/Ea)...
April 2017: Physiological Reports
https://www.readbyqxmd.com/read/28370024/prefrontal-oxygenation-and-the-acoustic-startle-eyeblink-response-during-exercise-a-test-of-the-dual-mode-model
#13
Gavin D Tempest, Gaynor Parfitt
The interplay between the prefrontal cortex and amygdala is proposed to explain the regulation of affective responses (pleasure/displeasure) during exercise as outlined in the dual-mode model. However, due to methodological limitations the dual-mode model has not been fully tested. In this study, prefrontal oxygenation (using near-infrared spectroscopy) and amygdala activity (reflected by eyeblink amplitude using acoustic startle methodology) were recorded during exercise standardized to metabolic processes: 80% of ventilatory threshold (below VT), at the VT, and at the respiratory compensation point (RCP)...
March 30, 2017: Psychophysiology
https://www.readbyqxmd.com/read/28362512/prognostic-role-of-cardiopulmonary-exercise-testing-in-clinical-practice
#14
Stefania Paolillo, Piergiuseppe Agostoni
Risk stratification is a mainstay in the care of cardiac and pulmonary disorders, as the identification of adverse outcomes helps provide measures to improve survival and quality of life. Cardiopulmonary exercise test is a useful prognostic tool in the clinical evaluation of several pathological conditions, such as heart diseases, respiratory disorders, and pulmonary hypertension. If not contraindicated, a cardiopulmonary exercise test should always be performed and integrated with clinical, laboratory, and hemodynamic parameters to better stratify patient risk...
March 31, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28343364/comparison-between-the-effect-of-6-weeks-of-morning-or-evening-aerobic-exercise-on-appetite-and-anthropometric-indices-a-randomized-controlled-trial
#15
Z Alizadeh, S Younespour, M Rajabian Tabesh, S Haghravan
Several studies have shown that exercise is directly related to creating negative energy balance and changes in appetite. However, few studies have examined the effect of exercise time during the day on these factors. The aim of the present study was to demonstrate the effect of 6 weeks of morning and evening aerobic exercise on appetite and anthropometric indices. A total of 48 overweight females were recruited to this clinical trial. By the time of exercise, they were divided into two groups (morning or evening) and performed 6 weeks of exercise with a target heart rate on the ventilatory threshold...
March 26, 2017: Clinical Obesity
https://www.readbyqxmd.com/read/28338363/decrement-in-professional-cyclists-performance-after-a-grand-tour
#16
Jose A Rodríguez-Marroyo, José G Villa, Raúl Pernía, Carl Foster
PURPOSE: The aim of this study was to analyze professional cyclists' performance decline after, and the exercise demands during, a Grand Tour. METHOD: Seven professional cyclists performed two incremental exercise tests, 1-week before and the day after the Vuelta España. During the race the exercise demands were analyzed on the basis of the HR. Three intensity zones were established according to reference HR values corresponding to the ventilatory (VT) and respiratory compensation (RCT) thresholds determined during the pre-race test...
March 24, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28303944/relationships-between-strength-and-endurance-parameters-and-air-depletion-rates-in-professional-firefighters
#17
Stephanie Windisch, Wolfgang Seiberl, Ansgar Schwirtz, Daniel Hahn
The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m(2)) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m)...
March 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28299717/physical-activity-and-maximal-oxygen-uptake-in-adults-with-prader-willi-syndrome
#18
Itai Gross, Harry J Hirsch, Naama Constantini, Shachar Nice, Yehuda Pollak, Larry Genstil, Talia Eldar-Geva, Varda Gross Tsur
BACKGROUND: Prader-Willi Syndrome (PWS) is the most common genetic syndrome causing life-threatening obesity. Strict adherence to a low-calorie diet and regular physical activity are needed to prevent weight gain. Direct measurement of maximal oxygen uptake (VO2 max), the "gold standard" for assessing aerobic exercise capacity, has not been previously described in PWS. OBJECTIVES: Assess aerobic capacity by direct measurement of VO2 max in adults with PWS, and in age and BMI-matched controls (OC), and compare the results with values obtained by indirect prediction methods...
March 16, 2017: Eating and Weight Disorders: EWD
https://www.readbyqxmd.com/read/28288012/influence-of-upper-body-exercise-on-the-fatigability-of-human-respiratory-muscles
#19
Nicholas B Tiller, Ian G Campbell, Lee M Romer
PURPOSE: Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. METHODS: Seven healthy men (mean±SD: age 24±4 y; peak O2 uptake [V[Combining Dot Above]O2 peak] 31.9±5.3 ml/kg/min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas-exchange threshold and V[Combining Dot Above]O2 peak...
March 10, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28271801/pediatric-aerobic-fitness-and-trainability
#20
Neil Armstrong
Three papers which between them raise controversial issues, apply laboratory measures to sport performance, and expose gaps in knowledge were selected for commentary. The first paper (Sports Med. 2016;46:1451-1460) reviews the literature on peak V̇O2 in relation to body size and recommends that peak V̇O2 in youth is best expressed via allometric scaling of lean body mass. The second paper (Pediatr Exerc Sci. 2016;28:456-465) reports that maturity status has no effect on peak V̇O2, respiratory compensation point, or ventilatory threshold in youth soccer players once data have been allometrically normalized by lower limb muscle volume...
February 2017: Pediatric Exercise Science
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