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Respiratory exchange ratio in performance

Kurt A Escobar, Jacobo Morales, Trisha A Vandusseldorp
CrossFit is a metabolically demanding strength and conditioning method which performance may benefit from a carbohydrate (CHO)-rich diet. This study investigated the effect of three consecutive days of high CHO intake on CrossFit performance and corresponding metabolically -related variables in strength trained individuals. Eighteen subjects with a CHO intake of <6 g/kg/day were randomly assigned into a CHO (n = 9) or control (C) group (n =9) and underwent a 9-day training protocol. During days 1, 5, and 9, performance was measured as repetitions completed during a 12 minute CrossFit workout...
2016: International Journal of Exercise Science
Kevin Forton, Yoshiki Motoji, Gael Deboeck, Vitalie Faoro, Robert Naeije
There has been revival of in interest in exercise testing of the pulmonary circulation for the diagnosis of pulmonary vascular disease, but there still is uncertainty about body position and the most relevant measurements. Doppler echocardiography pulmonary hemodynamic measurements were performed at progressively increased workload in 26 healthy adult volunteers in supine, semi-recumbent and upright positions which were randomly assigned at 24 hours intervals. Mean pulmonary artery pressure (mPAP) was estimated from the maximum tricuspid regurgitation jet velocity...
October 7, 2016: Journal of Applied Physiology
Nastasia Marinus, Liene Bervoets, Guy Massa, Kenneth Verboven, An Stevens, Tim Takken, Dominique Hansen
BACKGROUND: Cardiopulmonary exercise testing is advised ahead of exercise intervention in obese adolescents to assess medical safety of exercise and physical fitness. Optimal validity and reliability of test results are required to identify maximal exercise effort. As fat oxidation during exercise is disturbed in obese individuals, it remains an unresolved methodological issue whether the respiratory gas exchange ratio (RER) is a valid marker for maximal effort during exercise testing in this population...
October 20, 2016: Journal of Sports Medicine and Physical Fitness
Raoyrin Chanavirut, Pattarapong Makarawate, Ian A Macdonald, Naruemon Leelayuwat
BACKGROUND: Imbalances of the autonomic nervous (ANS), the cardiovascular system, and ionics might contribute to the manifestation of The Brugada Syndrome (BrS). Thus, this study has aimed to investigate the cardio-respiratory fitness and the responses of the ANS both at rest and during a sub-maximal exercise stress test, in BrS patients and in gender-matched and age-matched healthy sedentary controls. METHODS: Eleven BrS patients and 23 healthy controls were recruited in Khon Kaen, Thailand...
October 2016: Journal of Arrhythmia
Kenneth J Hunt, Prasanna Anandakumaran, Jonas A Loretz, Jittima Saengsuwan
PURPOSE: Self-paced maximal testing methods may be able to exploit central mediation of function-limiting fatigue and therefore have potential to generate more valid estimates of peak oxygen uptake. The aim of this study was to investigate the feasibility of a new method for self-paced peak performance testing on treadmills and to compare peak and submaximal performance outcomes with those obtained using a non-self-paced ('computer-paced') method employing predetermined speed and slope profiles...
September 28, 2016: Clinical Physiology and Functional Imaging
Mohamed Ayachi, Romain Niel, Iman Momken, Véronique L Billat, Laurence Mille-Hamard
In the field of comparative physiology, it remains to be established whether the concept of VO2max is valid in the mouse and, if so, how this value can be accurately determined. In humans, VO2max is generally considered to correspond to the plateau observed when VO2 no longer rises with an increase in workload. In contrast, the concept of VO2peak tends to be used in murine studies. The objectives of the present study were to determine whether (i) a continuous ramp protocol yielded a higher VO2peak than a stepwise, incremental protocol, and (ii) the VO2peak measured in the ramp protocol corresponded to VO2max...
2016: Frontiers in Physiology
Yvonne Kilian, Florian Engel, Patrick Wahl, Silvia Achtzehn, Billy Sperlich, Joachim Mester
PURPOSE: The aim of the present study was to compare the effects of high-intensity interval training (HIIT) vs high-volume training (HVT) on salivary stress markers [cortisol (sC), testosterone (sT), alpha-amylase (sAA)], metabolic and cardiorespiratory response in young athletes. METHODS: Twelve young male cyclists (14 ± 1 years; 57.9 ± 9.4 mL min(-1) kg(-1) peak oxygen uptake) performed one session of HIIT (4 × 4 min intervals at 90-95 % peak power output separated by 3 min of active rest) and one session of HVT (90 min constant load at 60 % peak power output)...
September 10, 2016: European Journal of Applied Physiology
Matthew A Wyon, Nick Allen, Ross Cloak, Sarah Beck, Paul Davies, Frances Clarke
An athlete's cardiorespiratory profile, maximal aerobic capacity, and anaerobic threshold is affected by training regimen and competition demands. The present study aimed to ascertain whether there are company rank differences in maximal aerobic capacity and anaerobic threshold in elite classical ballet dancers. Seventy-four volunteers (M 34, F 40) were recruited from two full-time professional classical ballet companies. All participants completed a continuous incremental treadmill protocol with a 1-km/hr speed increase at the end of each 1-min stage until termination criteria had been achieved (e...
September 2016: Medical Problems of Performing Artists
Qi Liu, Yonghua Gao, Rongchang Chen, Zhe Cheng
BACKGROUND: Noninvasive ventilation (NIV) has proved to be a useful technique for breathing support. However, complications, discomfort, and failure of NIV were commonly caused by the mask. Therefore, the helmet was developed to improve performance and reduce complications; however, there has been no conclusive results on its effect until now. Thus, we performed a systematic review and meta-analysis to investigate the effect of NIV with a helmet versus the control strategy in patients with acute respiratory failure (ARF)...
2016: Critical Care: the Official Journal of the Critical Care Forum
L S Paes, J P Borges, F A Cunha, M G C Souza, F Z G A Cyrino, D A Bottino, E Bouskela, P Farinatti
This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min)...
July 28, 2016: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
Matthew Zimmerman, Grant Landers, Karen E Wallman
This study examined the effects of pre-cooling via ice ingestion on female cycling performance in hot, humid conditions. Ten female endurance athletes, mean age (28±6 y), height (167.6±6.5 cm) and body-mass (68.0±11.5 kg) participated in the study. Participants completed an 800 kJ cycle time-trial in hot, humid conditions (34.9±0.3°C, 49.8±3.5% RH). This was preceded by the consumption of 7 g·kg(-1) of crushed ice (ICE) or water (CON). There was no difference in performance time (CON 3851±449 s; ICE 3767±465 s), oxygen consumption (CON 41...
August 24, 2016: International Journal of Sport Nutrition and Exercise Metabolism
Baptiste Chéhère, Valérie Bougault, Alice Gicquello, Benoit Wallaert
INTRODUCTION: The 6-minute stepper test (6MST) has been used as an alternative to the 6-minute walk test (6MWT) to assess exercise tolerance in patients with interstitial lung disease (ILD). Recent data suggest that the tests may involve different energy pathways and cardiorespiratory responses. We thus aimed to compare the cardiorespiratory responses of ILD patients during the 6MWT and the 6MST. METHODS: Thirty-one patients with ILD were randomised to perform both tests in the order 6MST→6MWT (n=16) or 6MWT→6MST (n=15)...
July 18, 2016: Medicine and Science in Sports and Exercise
Xiong Zhang, Bo Yu, Dan Yang, Zhengdong Qiao, Ting Cao, Peng Zhang
BACKGROUND: Roux-en-Y gastric bypass (RYGB) has shown positive outcomes in the remission of type 2 diabetes (T2D) and weight loss in obese patients by inhibiting food intake and nutrient absorption as well as inducing favorable hormonal changes. The purpose of the present study was to investigate whether gastric volume reduction is still required in addition to intestinal bypass for the purpose of T2D remission in nonobese patients. SETTING: University Medical Center...
April 20, 2016: Surgery for Obesity and related Diseases: Official Journal of the American Society for Bariatric Surgery
Bonnie Stevens, Janet Yamada, Arne Ohlsson, Sarah Haliburton, Allyson Shorkey
BACKGROUND: Administration of oral sucrose with and without non-nutritive sucking is the most frequently studied non-pharmacological intervention for procedural pain relief in neonates. OBJECTIVES: To determine the efficacy, effect of dose, method of administration and safety of sucrose for relieving procedural pain in neonates as assessed by validated composite pain scores, physiological pain indicators (heart rate, respiratory rate, saturation of peripheral oxygen in the blood, transcutaneous oxygen and carbon dioxide (gas exchange measured across the skin - TcpO2, TcpCO2), near infrared spectroscopy (NIRS), electroencephalogram (EEG), or behavioural pain indicators (cry duration, proportion of time crying, proportion of time facial actions (e...
2016: Cochrane Database of Systematic Reviews
A Foreman, R J De Santis, F Sultanov, D J Enepekides, K M Higgins
BACKGROUND: Total laryngectomy (TL) is an appropriate oncologic operation for many patients with laryngeal cancer delivering excellent oncologic outcomes, however it remains beset with significant functional consequences. Following TL, the upper and lower airways are permanently disconnected, which causes unfiltered, cold air with reduced humidity to enter the tracheobronchial tree, resulting in mucus overproduction and an increase in the viscosity of the mucus. In response to this, Heat and moisture exchangers were developed to compensate for the lost functions of the upper respiratory tract and their effect on the patients' respiratory performance in addition to their quality of life...
2016: Journal of Otolaryngology—Head & Neck Surgery
Elvis De Souza Malta, Rodrigo Araujo Bonetti De Poli, Gabriel Motta Pinheiro Brisola, Fabio Milioni, Willian Eiji Miyagi, Fabiana Andrade Machado, Alessandro Moura Zagatto
The purpose of this study was to investigate the acute effects of photobiomodulation therapy using cluster light-emitting diodes (LEDT; 104 diodes) (wavelength 660 and 850 nm; energy density 1.5 and 4.5 J/cm(2); energy 60 J at each point; total energy delivered 600 J) on alternative maximal accumulated oxygen deficit (MAODALT) and time to exhaustion, during a high-intensity running effort. Fifteen moderately active and healthy males (age 25.1 ± 4.4 years) underwent a graded exercise test and two supramaximal exhaustive efforts at 115 % of the intensity associated with maximal oxygen uptake performed after acute LEDT or placebo irradiation in a double-blind, crossover, and placebo-controlled study design...
September 2016: Lasers in Medical Science
Christopher J Stevens, Kyle J M Bennett, Dean V Sculley, Robin Callister, Lee Taylor, Ben J Dascombe
The purpose of this investigation was to assess the effect of combining practical methods to cool the body on endurance running performance and physiology in the heat. Eleven trained male runners completed four randomised, pre-loaded running time trials (20 min at 70% VO2max and a 3 km time trial) on a non-motorised treadmill in the heat (33°C). Trials consisted of pre-cooling by combined cold-water immersion and ice slurry ingestion (PRE), mid-cooling by combined facial water spray and menthol mouth rinse (MID), a combination of all methods (ALL) and control (CON)...
June 29, 2016: Journal of Strength and Conditioning Research
Maria Tinoco-Fernández, Miguel Jiménez-Martín, M Angeles Sánchez-Caravaca, Antonio M Fernández-Pérez, Jesús Ramírez-Rodrigo, Carmen Villaverde-Gutiérrez
Although all authors report beneficial health changes following training based on the Pilates method, no explicit analysis has been performed of its cardiorespiratory effects. The objective of this study was to evaluate possible changes in cardiorespiratory parameters with the Pilates method. A total of 45 university students aged 18-35 years (77.8% female and 22.2% male), who did not routinely practice physical exercise or sports, volunteered for the study and signed informed consent. The Pilates training was conducted over 10 weeks, with three 1-hour sessions per week...
July 2016: Research in Sports Medicine
Andrei Gribok, Jayme L Leger, Michelle Stevens, Reed Hoyt, Mark Buller, William Rumpler
The paper demonstrates that minute-to-minute metabolic response to meals with different macronutrient content can be measured and discerned in the whole-body indirect calorimeter. The ability to discriminate between high-carbohydrate and high-fat meals is achieved by applying a modified regularization technique with additional constraints imposed on oxygen consumption rate. These additional constraints reduce the differences in accuracy between the oxygen and carbon dioxide analyzers. The modified technique was applied to 63 calorimeter sessions that were each 24 h long...
June 2016: Physiological Reports
Mojsije Andjic, Dejan Spiroski, Olivera Ilic Stojanovic, Tijana Vidakovic, Milica Lazovic, Dragan Babic, Arsen Ristic, Sanja Mazic, Marija Zdravkovic, Petar Otasevic
BACKGROUND: Exercise-based rehabilitation is an important part of treatment patients following acute myocardial infarction (MI). However, data are scarce on the efffects of short-term exercise programs in patients with acute MI treated with primary percutaneous coronary intervention (PPCI). AIM: To evaluate the effect of short-term exercise training on cardiopulmonary exercise testing (CPET) parameters in patients suffering acute MI treated with PPCI. STUDY DESIGN: Observational longitudinal study...
June 2016: European Journal of Physical and Rehabilitation Medicine
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