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Normobaric hypoxia

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https://www.readbyqxmd.com/read/28782598/physiological-and-performance-effects-of-nitrate-supplementation-during-roller-skiing-in-normoxia-and-normobaric-hypoxia
#1
Linn Nybäck, Caroline Glännerud, Gustav Larsson, Eddie Weitzberg, Oliver Michael Shannon, Kerry McGawley
The present study examined the effects of acute nitrate (NO3(-)) supplementation ingested in the form of concentrated beetroot juice on cross-country roller-ski performance in normoxia (N) and normobaric hypoxia (H). Eight competitive cross-country skiers (five males: age 22 ± 3 years, V·O2max 71.5 ± 4.7 mL kg(-1)·min(-1); three females: age 21 ± 1 years, V·O2max 58.4 ± 2.5 mL kg(-1)·min(-1)) were supplemented with a single dose of NO3(-)-rich beetroot juice (BRJ, ∼13 mmol NO3(-)) or a NO3(-)-depleted placebo (PL, ∼0 mmol NO3(-)) and performed 2 x 6-min submaximal exercise bouts and a 1000-m time-trial (TT) on a treadmill in N (20...
August 4, 2017: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/28775065/effect-of-hypoxia-and-hyperoxia-on-exercise-performance-in-healthy-individuals-and-in-patients-with-pulmonary-hypertension-a-systematic-review
#2
Silvia Ulrich, Simon Raphael Schneider, Konrad E Bloch
Exercise performance is determined by oxygen supply to working muscles and vital organs. In healthy individuals, exercise performance is limited in the hypoxic environment at altitude, when oxygen delivery is diminished due to the reduced alveolar and arterial oxygen partial pressures. In patients with pulmonary hypertension, exercise performance is already reduced near sea level due to impairments of the pulmonary circulation and gas exchange and, presumably, these limitations are more pronounced at altitude...
August 3, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28774953/cerebrovascular-and-ventilatory-responses-to-acute-normobaric-hypoxia-in-girls-and-women
#3
Laura E Morris, Daniela Flück, Philip N Ainslie, Ali M McManus
Physiological responses to hypoxia in children are incompletely understood. We aimed to characterize cerebrovascular and ventilatory responses to normobaric hypoxia in girls and women. Ten healthy girls (9.9 ± 1.7 years; mean ± SD; Tanner stage 1 and 2) and their mothers (43.9 ± 3.5 years) participated. Internal carotid (ICA) and vertebral artery (VA) velocity, diameter and flow (Duplex ultrasound) was recorded pre- and post-1 h of hypoxic exposure (FIO2 = 0.126;~4000 m) in a normobaric chamber...
August 2017: Physiological Reports
https://www.readbyqxmd.com/read/28765942/protein-kinase-c-isozyme-expression-in-right-ventricular-hypertrophy-induced-by-pulmonary-hypertension-in-chronically-hypoxic-rats
#4
Chao Zeng, Bin Liang, Rui Jiang, Yiwei Shi, Yongcheng Du
In chronic hypoxia, pulmonary hypertension (PH) induces right ventricular hypertrophy (RVH). Evidence indicates that protein kinase C (PKC) serves a crucial role in hypoxia‑induced RVH. The present study investigated PKC isoform-specific expression and its involvement in RVH. Rats were exposed to normobaric hypoxia for a number of days to induce PH. PKC isoform‑specific membrane translocation and protein expression in the myocardium were evaluated by western blotting and immunostaining. A total of six isoforms of conventional PKC (cPKC; α, βI and βII) and of novel PKC (nPKC; δ, ε and η), were detected in the rat myocardium...
July 27, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28763443/intermittent-hypoxic-training-improves-anaerobic-performance-in-competitive-swimmers-when-implemented-into-a-direct-competition-mesocycle
#5
Miłosz Czuba, Robert Wilk, Jakub Karpiński, Małgorzata Chalimoniuk, Adam Zajac, Józef Langfort
The main objective of this research was to evaluate the efficacy of intermittent hypoxic training (IHT) on anaerobic and aerobic capacity and swimming performance in well-trained swimmers. Sixteen male swimmers were randomly divided into a hypoxia (H) group (n = 8), which trained in a normobaric hypoxia environment, and a control (C) group (n = 8), which exercised under normoxic conditions. However, one participant left the study without explanation. During the experiment group H trained on land twice per week in simulated hypoxia (FiO2 = 15...
2017: PloS One
https://www.readbyqxmd.com/read/28757365/assessing-chemoreflexes-and-oxygenation-in-the-context-of-acute-hypoxia-implications-for-field-studies
#6
Jamie R Pfoh, Craig D Steinback, Emily R Vanden Berg, Christina D Bruce, Trevor A Day
Carotid chemoreceptors detect changes in PO2 and elicit a peripheral respiratory chemoreflex (PCR). The PCR can be tested through a transient hypoxic ventilatory response test (TT-HVR), which may not be safe nor feasible at altitude. We characterized a transient hyperoxic ventilatory withdrawal test in the setting of steady-state normobaric hypoxia (13.5-14% FIO2) and compared it to a TT-HVR and a steady-state poikilocapnic hypoxia test, within-individuals. No PCR test magnitude was correlated with any other test, nor was any test magnitude correlated with oxygenation while in steady-state hypoxia...
July 27, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28752154/epidemiology-pathophysiology-clinical-evaluation-and-treatment-of-carbon-monoxide-poisoning-in-child-infant-and-fetus
#7
REVIEW
Atilla Alp Gozubuyuk, Huseyin Dag, Alper Kacar, Yakup Karakurt, Vefik Arica
Carbon monoxide (CO) poisoning is one of the most common types of poisoning causing death worldwide. In our country, it occurs particularly during winter as a result of leak from stove or water heater, or as result of inhalation during a fire. Although most poisonings occur accidentally, some cases are suicide attempt. As CO is a substance that is not visible and has no taste or smell and is therefore difficult to detect, the gas can be a "silent killer" that is not noticed until effects develop. CO reacts with oxygen, creating carboxy hemoglobin (COHb), which leads to tissue hypoxia...
2017: Northern Clinics of Istanbul
https://www.readbyqxmd.com/read/28744647/antioxidant-and-antiamnestic-effects-of-potassium-comenate-and-comenic-acid-under-conditions-of-normobaric-hypoxia-with-hypercapnia
#8
L V Shurygina, E I Zlishcheva, A N Kravtsova, A A Kravtsov
Potassium comenate and comenic acid exhibit manifest and virtually identical antioxidant activity under conditions of hypoxia with hypercapnia. The effects of these drugs on conditioned reflex training with positive reinforcement differ significantly. Potassium comenate promotes retention of the learning capacity and memory in hypoxic rats at the level of intact control, that is, exhibits a pronounced protective antiamnestic effect, while comenic acid only facilitates training of the conditioned reflex with positive reinforcement...
July 26, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28721516/motor-cognitive-dual-tasking-under-hypoxia
#9
Dennis Hamacher, Marie Brennicke, Tom Behrendt, Prisca Alt, Alexander Törpel, Lutz Schega
Hypoxic conditions diminish motor performance and cognitive functions, especially when the motor task and the cognitive task are conducted simultaneously. Hypoxia does further increase prefrontal cortex activity which provokes a reduced capability of efficient resource utilisation. This, again, might evoke that the capacity of the limited mental resources of a dual task will be reached at an earlier stage of task complexity. The purpose of our study was to examine whether a cognitive task would increase gait variability to a higher extent under hypoxic as compared to normoxic conditions...
July 18, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28705998/is-normobaric-hypoxia-an-effective-treatment-for-sustaining-previously-acquired-altitude-acclimatization
#10
Beth A Beidleman, Charles S Fulco, Bruce S Cadarette, Allen Cymerman, Mark J Buller, Roy M Salgado, Alexander M Posch, Janet E Staab, Ingrid V Sils, Beau R Yurkevicius, Adam J Luippold, Alexander P Welles, Stephen R Muza
This study examined whether normobaric hypoxia (NH) treatment is more efficacious for sustaining high altitude (HA) acclimatization during re-introduction to altitude (RA) than no treatment at all. Seventeen sea level (SL) residents (age=23±6yrs; mean±SE) completed in the following order: 1)4d of SL testing, 2)12d of high altitude (HA) acclimatization at 4300m, 3)12d at SL post HA acclimatization (Post) where each received either NH (n=9;FiO2=0.122) or Sham (n=8;FiO2=0.207) treatment, and 4)24-h re-introduction to 4300m altitude (RA) in a hypobaric chamber...
July 13, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28699679/one-session-of-remote-ischemic-preconditioning-does-not-improve-vascular-function-in-acute-normobaric-and-chronic-hypobaric-hypoxia
#11
Mathew G Rieger, Ryan L Hoiland, Joshua C Tremblay, Mike Stembridge, Anthony R Bain, Daniela Flück, Prajan Subedi, James D Anholm, Philip N Ainslie
Application of repeated short duration bouts of ischemia to the limbs, termed remote ischemic preconditioning (RIPC), is a novel technique that may have protective effects on vascular function during hypoxic exposures. In separate parallel-design studies, at sea-level (SL; n = 16), and after 8-12 days at high-altitude (HA; n = 12; White Mountain, 3800 m), participants underwent either a sham protocol or one session of 4 × 5 minutes of dual-thigh cuff occlusion with 5 minutes recovery. Brachial artery flow-mediated dilation (FMD; ultrasound), pulmonary artery systolic pressure (PASP; echocardiography), and internal carotid artery flow (ICA; ultrasound) were measured at SL in normoxia and isocapnic hypoxia [end-tidal PO₂ (PETO₂) maintained to 50 mmHg], and during normal breathing at HA...
July 12, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28694491/measuring-the-energy-of-ventilation-and-circulation-during-human-walking-using-induced-hypoxia
#12
Masahiro Horiuchi, Yoshiyuki Fukuoka, Yoko Handa, Daijiro Abe, Herman Pontzer
Energy expenditure (EE) during walking includes energy costs to move and support the body and for respiration and circulation. We measured EE during walking under three different oxygen concentrations. Eleven healthy, young, male lowlanders walked on a treadmill at seven gait speeds (0.67-1.83 m s(-1)) on a level gradient under normobaric normoxia (room air, 21% O2), moderate hypoxia (15% O2), and severe hypoxia (11% O2). By comparing the hypoxia-induced elevation in heart rate (HR [bpm]), ventilation (VE [L min(-1)]) with the change in energy expenditure (EE [W]) at each speed, we were able to determine circulatory and respiratory costs...
July 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28686073/effect-of-hypoxia-on-bold-fmri-response-and-total-cerebral-blood-flow-in-migraine-with-aura-patients
#13
Nanna Arngrim, Anders Hougaard, Henrik W Schytz, Mark B Vestergaard, Josefine Britze, Faisal Mohammad Amin, Karsten S Olsen, Henrik Bw Larsson, Jes Olesen, Messoud Ashina
Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28684191/effects-of-oral-sodium-nitrate-on-forearm-blood-flow-oxygenation-and-exercise-performance-during-acute-exposure-to-hypobaric-hypoxia-4300%C3%A2-m
#14
Heath G Gasier, Anthony R Reinhold, Allison R Loiselle, Shawn E Soutiere, David M Fothergill
A reduction in oxygen transport contributes to impaired exercise capacity at high altitude. Since blood flow is mediated, in part, by nitric oxide (NO), we hypothesized that sodium nitrate provided before forearm grip exercise performed at a simulated altitude of 4300 m (hypobaric hypoxia (HH)) would increase forearm blood flow and oxygenation, and decrease the decrement in grip performance. In a double-blind, randomized crossover study, 10 healthy subjects (9 males and 1 female) performed continuous (CGrip) and repeated rhythmic (RGrip) isometric forearm exercise until task failure in normobaric normoxia (NN), 2...
July 3, 2017: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/28679682/normobaric-hypoxic-conditioning-to-maximise-weight-loss-and-ameliorate-cardio-metabolic-health-in-obese-populations-a-systematic-review
#15
Liam Gray Hobbins, Steve Hunter, Nadia Gaoua, Olivier Girard
Normobaric hypoxic conditioning (HC) denotes exposure to hypoxia at rest (passive) or combined with exercise (active). HC has been applied acutely (single exposure) and chronically (repeated exposure) to obese populations for managing/increasing cardio-metabolic health and weight loss. Cardio-metabolic health and weight loss responses of obese populations in response to passive and active HC are unclear. A systematic search for articles published between 2000-2017 was carried out. Studies investigating the effects of HC for improving cardio-metabolic health and weight loss of obese populations were included...
July 5, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28657365/acute-hypobaric-hypoxia-augments-rock2-protein-level-and-activity
#16
Priyanka Pandey, Sangeeta Kumari, Zahara Ali, Ma Qadar Pasha
AIM: Rho kinase activation plays an important role in hypoxic pulmonary vasoconstriction and increased vascular resistance. The present study investigated changes in the level and activity of rho kinase isoform 2 (ROCK2) under acute hypobaric hypoxia exposure. For this, Wistar rats were taken as the model organism. MATERIALS AND METHODS: Fifteen male Wistar rats (4-6 week old, 250 grams) were normalized with the surrounding environment by providing a 12/12 hour day and night acclimatization cycle...
June 28, 2017: Experimental Lung Research
https://www.readbyqxmd.com/read/28649204/effects-of-dietary-nitrate-supplementation-on-physiological-responses-cognitive-function-and-exercise-performance-at-moderate-and-very-high-simulated-altitude
#17
Oliver M Shannon, Lauren Duckworth, Matthew J Barlow, Kevin Deighton, Jamie Matu, Emily L Williams, David Woods, Long Xie, Blossom C M Stephan, Mario Siervo, John P O'Hara
Purpose: Nitric oxide (NO) bioavailability is reduced during acute altitude exposure, contributing toward the decline in physiological and cognitive function in this environment. This study evaluated the effects of nitrate ([Formula: see text]) supplementation on NO bioavailability, physiological and cognitive function, and exercise performance at moderate and very-high simulated altitude. Methods:Ten males (mean (SD): [Formula: see text]: 60.9 (10.1) ml·kg(-1)·min(-1)) rested and performed exercise twice at moderate (~14...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28641679/normobaric-hypoxia-and-submaximal-exercise-effects-on-running-memory-and-mood-state-in-women
#18
Yongsuk Seo, Hayden D Gerhart, Jon Stavres, Curtis Fennell, Shane Draper, Ellen L Glickman
BACKGROUND: An acute bout of exercise can improve cognitive function in normoxic and hypoxic conditions. However, limited research supports the improvement of cognitive function and mood state in women. The purpose of this study was to examine the effects of hypoxia and exercise on working memory and mood state in women. METHODS: There were 15 healthy women (age = 22 ± 2 yr) who completed the Automated Neuropsychological Assessment Metrics-4th Edition (ANAM), including the Running Memory Continuous Performance Task (RMCPT) and Total Mood Disturbance (TMD) in normoxia (21% O2), at rest in normoxia and hypoxia (12...
July 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28625661/resting-limb-muscle-perfusion-during-inspiratory-muscle-loading-in-hypoxia-and-normoxia
#19
Hannes Klenze, Thomas Christian Köhler, Franziska Farquharson, Stephan Walterspacher, Daniel Duerschmied, Kai Roecker, Hans-Joachim Kabitz, David Johannes Walker
INTRODUCTION: Fatiguing of respiratory muscles reduces peripheral muscle perfusion. Further, acute hypoxia enhances respiratory muscle fatigue. This study investigated the effects of inspiratory muscle loading (IML) on resting locomotor muscle perfusion in hypoxia compared to normoxia. METHODS: Ten subjects completed two study days of fatiguing IML (blinded, randomized) in normobaric hypoxia (targeted oxygen saturation 80%) and normoxia, respectively. Contrast-enhanced ultrasound (CEUS) of the gastrocnemius muscle and popliteal doppler ultrasonography were used to monitor muscle perfusion...
June 15, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28620311/physiological-adaptations-to-hypoxic-vs-normoxic-training-during-intermittent-living-high
#20
Stefan De Smet, Paul van Herpt, Gommaar D'Hulst, Ruud Van Thienen, Marc Van Leemputte, Peter Hespel
In the setting of "living high," it is unclear whether high-intensity interval training (HIIT) should be performed "low" or "high" to stimulate muscular and performance adaptations. Therefore, 10 physically active males participated in a 5-week "live high-train low or high" program (TR), whilst eight subjects were not engaged in any altitude or training intervention (CON). Five days per week (~15.5 h per day), TR was exposed to normobaric hypoxia simulating progressively increasing altitude of ~2,000-3,250 m...
2017: Frontiers in Physiology
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