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Hypoxia and exercise

Eric Hermand, François J Lhuissier, Nicolas Voituron, Jean-Paul Richalet
We evaluated the mechanisms responsible for the instability of ventilation control system under simultaneous metabolic (exercise) and environmental (hypoxia) stresses, promoting the genesis of periodic breathing. A model following the main concepts of ventilatory control has been tested, including cardiovascular and respiratory parameters, characteristics of peripheral and central chemoreceptors, at mild exercise in hypoxia (FIO2=0.145). Interaction between O2 and CO2 sensing was introduced following three different modalities...
October 12, 2016: Journal of Theoretical Biology
Hsing-Hua Tsai, Shao-Chiang Chang, Cheng-Hsien Chou, Tzu-Pin Weng, Chih-Chin Hsu, Jong-Shyan Wang
This study elucidates how interval and continuous exercise regimens affect the mitochondrial functionality of lymphocytes under hypoxic stress. Sixty healthy sedentary males were randomly assigned to engage in either high-intensity interval training (HIIT, 3 min intervals at 80% and 40% VO2max, n = 20) or moderate-intensity continuous training (MICT, sustained 60% VO2max, n = 20) for 30 min/day, 5 days/week for 6 weeks or were assigned to a control group that did not receive exercise intervention (n = 20)...
October 12, 2016: Scientific Reports
Hiroshi Nagahisa, Kazutaka Mukai, Hajime Ohmura, Toshiyuki Takahashi, Hirofumi Miyata
Hypoxic training is believed to increase endurance capacity in association with hypoxia inducible factor-1α (HIF-1α), a modulator of vascular endothelial growth factor-A (VEGF-A), and to influence activation of satellite cells (SCs). However, the effect of hypoxic training on SC activation and its relation to angiogenesis has not been thoroughly investigated. Eight Thoroughbred horses were subjected to normoxic (FIO2 = 21%) or hypoxic (FIO2 = 15%) training for 3 days/week (100%  [Formula: see text]) for 4 weeks...
2016: Oxidative Medicine and Cellular Longevity
Alex J Wadley, Ida S Svendsen, Michael Gleeson
Altitude exposure can exaggerate the transient increase in markers of oxidative stress observed following acute exercise. However, these responses have not been monitored in endurance-trained cyclists at altitudes typically experienced whilst training. Endurance trained males (n=12; mean (±SD) age: 28 ± 4 years, V̇O2max 63.7 ± 5.3 ml/kg/min) undertook two 75-min exercise trials at 70% relative V̇O2max; once in normoxia and once in hypobaric hypoxia, equivalent to 2000m above sea level (hypoxia). Blood samples were collected before, immediately after and 2 h post-exercise to assess plasma parameters of oxidative stress (protein carbonylation (PC), thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC) and catalase activity (CAT))...
October 6, 2016: International Journal of Sport Nutrition and Exercise Metabolism
Mathew J Wong, Crystal Kantores, Julijana Ivanovska, Amish Jain, Robert P Jankov
Chronic neonatal pulmonary hypertension (PHT) frequently results in early death. Systemically administered Rho-kinase (ROCK) inhibitors prevent and reverse chronic PHT in neonatal rats, but at the cost of severe adverse effects, including systemic hypotension and growth restriction. Simvastatin has pleiotropic inhibitory effects on isoprenoid intermediates that may limit activity of RhoA, which signals upstream of ROCK. We therefore hypothesized that statin treatment would safely limit pulmonary vascular RhoA activity and prevent and reverse experimental chronic neonatal PHT via downstream inhibitory effects on pathological ROCK activity...
September 30, 2016: American Journal of Physiology. Lung Cellular and Molecular Physiology
Dale R Wagner, Skyler Saunders, Brady Robertson, John E Davis
: Wagner, Dale R., Skyler Saunders, Brady Robertson, and John E. Davis. Normobaric hypoxia effects on balance measured by computerized dynamic posturography. High Alt Med Biol. 17:222-227, 2016.-Background/Aim: Equilibrium was measured by computerized dynamic posturography at varying levels of normobaric hypoxia before and after exercise. METHODS: Following a familiarization trial, 12 males (27.3 ± 7.1 years) completed three sessions in random order on a NeuroCom SMART Balance Master: a sham trial at the ambient altitude of 1500 m and simulated altitudes of 3000 and 5000 m created by a hypoxic generator...
September 2016: High Altitude Medicine & Biology
Stéphane Doutreleau, Irina Enache, Cristina Pistea, Fabrice Favret, Evelyne Lonsdorfer, Stéphane Dufour, Anne Charloux
We measured the effects of adding CO2 to an inhaled hypoxic gas mixture on cardio-respiratory parameters during maximal exercise. Eight young males performed four incremental maximal exercise tests on cycle under ambient air, hypoxia (FIO2 0.125), inhaled CO2 (FICO2 0.045), and combination of hypoxia and inhaled CO2. The highest ventilation (VE) and VE/CO2 output were recorded in CO2 inhalation and combined treatments. Arterial O2 partial pressure was higher in combined than in hypoxia treatment, but the difference between the treatments narrowed from rest to end-exercise, at least partly because the magnitude of the increase in VE (%) at exercise was smaller in combined treatment than in hypoxia...
September 26, 2016: Respiratory Physiology & Neurobiology
Brendan R Scott, Katie M Slattery, Dean V Sculley, Catriona Lockhart, Ben J Dascombe
This study assessed whether hypoxia augments anabolic responses to moderate-load resistance exercise. Fourteen trained males performed moderate-load resistance exercise in normoxia (NORM; fraction of inspired oxygen [FIO2] = 21%) and moderate-level hypoxia (MH; FIO2 = 16%). Exercise comprised 3 sets of 10 repetitions of squats and deadlifts at 60% of 1-repetition maximum, with 60 s inter-set rest. Blood lactate (BLa) was quantified after each exercise, while arterial oxygen saturation (SpO2) and heart rate (HR) were assessed following each set...
September 20, 2016: Journal of Strength and Conditioning Research
Piotr Niewinski, Dariusz Janczak, Artur Rucinski, Stanislaw Tubek, Zoar J Engelman, Pawel Piesiak, Przemyslaw Jazwiec, Waldemar Banasiak, Marat Fudim, Paul A Sobotka, Shahrokh Javaheri, Emma C J Hart, Julian F R Paton, Piotr Ponikowski
AIMS: Augmented reflex responses from peripheral chemoreceptors, which are mainly localized in the carotid bodies (CBs), characterize patients with systolic heart failure and contribute to adrenergic hyperactivation. We investigated whether surgical resection of CBs in these patients can be performed safely to decrease sympathetic tone. METHODS AND RESULTS: We studied 10 male patients with systolic heart failure (age, 59 ± 3 years; LVEF, 27 ± 7%) who underwent unilateral right-sided CB resection (four patients) or bilateral CB resection (six patients)...
September 20, 2016: European Journal of Heart Failure
T Pincez, L Calamy, Z Germont, A Lemoine, A-A Lopes, A Massiot, J Tencer, C Thivent, A Hadchouel
Acute and chronic pulmonary complications are frequent in sickle cell disease (SCD), with different spectrum and characteristics in children and adults. Chronic hypoxia is frequent and plays a role in several respiratory complications in SCD. Furthermore, hypoxia has been associated with a higher risk of cerebral ischemia. Despite differing oxygen affinity between hemoglobin A and S, standard pulse oximetry was shown to be accurate in diagnosing hypoxia in SCD patients. Whereas acute hypoxia management is similar to non-SCD patients, chronic hypoxia treatment is mainly based on a transfusion program rather than long-term oxygen therapy...
October 2016: Archives de Pédiatrie: Organe Officiel de la Sociéte Française de Pédiatrie
Samuel Helfer, Joseph Quackenbush, Michael Fletcher, David R Pendergast
BACKGROUND: Climbing and trekking at altitude are common recreational and military activities. Physiological effects of altitude are hypoxia and hyperventilation. The hyperventilatory response to altitude may cause respiratory muscle fatigue and reduce sustained submaximal exercise. Voluntary isocapnic hyperpnea respiratory muscle training (VIHT) improves exercise endurance at sea level and at depth. The purpose of this study was to test the hypothesis that VIHT would improve exercise time at altitude [3600 m (11,811 ft)] compared to control and placebo groups...
August 2016: Aerospace Medicine and Human Performance
Ilkka H A Heinonen, Robert Boushel, Kari K Kalliokoski
Adipose tissue metabolism and circulation play an important role in human health. It is well-known that adipose tissue mass is increased in response to excess caloric intake leading to obesity and further to local hypoxia and inflammatory signaling. Acute exercise increases blood supply to adipose tissue and mobilization of fat stores for energy. However, acute exercise during systemic hypoxia reduces subcutaneous blood flow in healthy young subjects, but the response in overweight or obese subjects remains to be investigated...
2016: Frontiers in Endocrinology
Leonid V Kapilevich, Tatyana A Kironenko, Anna N Zaharova, Yuri V Kotelevtsev, Nickolai O Dulin, Sergei N Orlov
During the last two decades numerous research teams demonstrated that skeletal muscles function as an exercise-dependent endocrine organ secreting dozens of myokines. Variety of physiological and pathophysiological implications of skeletal muscle myokines secretion has been described; however, upstream signals and sensing mechanisms underlying this phenomenon remain poorly understood. It is well documented that in skeletal muscles intensive exercise triggers dissipation of transmembrane gradient of monovalent cations caused by permanent activation of voltage-gated Na(+) and K(+) channels...
December 2015: Genes & Diseases
D R Slivka
No abstract text is available yet for this article.
September 2, 2016: Acta Physiologica
Shohei Dobashi, Masahiro Horiuchi, Junko Endo, Masataka Kiuchi, Katsuhiro Koyama
Dobashi, Shohei, Masahiro Horiuchi, Junko Endo, Masataka Kiuchi, and Katsuhiro Koyama. Cognitive function and cerebral oxygenation during prolonged exercise under hypoxia in healthy young males. High Alt Med Biol. 16:000-000, 2016.-The present study examined the effect of prolonged hypoxic exercise on cognitive function. Eight healthy male volunteers were required to complete exercise trials (four 30-minute cycling sessions with a 15-minute rest interval) at an intensity corresponding to 50% of their altitude-adjusted peak oxygen uptake under two different conditions: normoxia (room air at 400 m) and hypoxia (fraction of inspired oxygen: 0...
September 1, 2016: High Altitude Medicine & Biology
Keisho Katayama, Koji Ishida, Mitsuru Saito, Teruhiko Koike, Shigehiko Ogoh
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
David M Fothergill, Allison R Loiselle, Anthony R Reinhold
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Nobukazu Kasai, Chihiro Kojima, Kazushige Goto
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Rafael Torres-Peralta, José Losa-Reyna, David Morales-Alamo, Miriam González-Izal, Ismael Pérez-Suárez, Jesús G Ponce-González, Mikel Izquierdo, José A L Calbet
To determine the level of hypoxia from which muscle activation (MA) is reduced during incremental exercise to exhaustion (IE), and the role played by PIO2 in this process, ten volunteers (21 ± 2 years) performed four IE in severe acute hypoxia (SAH) (PIO2 = 73 mmHg). Upon exhaustion, subjects were asked to continue exercising while the breathing gas mixture was swiftly changed to a placebo (73 mmHg) or to a higher PIO2 (82, 92, 99, and 142 mmHg), and the IE continued until a new exhaustion. At the second exhaustion, the breathing gas was changed to room air (normoxia) and the IE continued until the final exhaustion...
2016: Frontiers in Physiology
Oliver Michael Shannon, Lauren Duckworth, Matthew John Barlow, David Woods, Jose Lara, Mario Siervo, John Paul O'Hara
Nitrate-rich beetroot juice (BRJ) increases plasma nitrite concentrations, lowers the oxygen cost (V⋅O2) of steady-state exercise and improves exercise performance in sedentary and moderately-trained, but rarely in well-trained individuals exercising at sea-level. BRJ supplementation may be more effective in a hypoxic environment, where the reduction of nitrite into nitric oxide (NO) is potentiated, such that well-trained and less well-trained individuals may derive a similar ergogenic effect. We conducted a randomised, counterbalanced, double-blind placebo controlled trial to determine the effects of BRJ on treadmill running performance in moderate normobaric hypoxia (equivalent to 2500 m altitude) in participants with a range of aerobic fitness levels...
September 30, 2016: Nitric Oxide: Biology and Chemistry
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