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Hypoxia and exercise

Mehrdad Behnia, Courtney M Wheatley, Alberto Avolio, Bruce D Johnson
BACKGROUND: During exercise as pulmonary blood flow rises, pulmonary capillary blood volume increases and gas exchange surface area expands through distention and recruitment. We have previously demonstrated that pulmonary capillary recruitment is limited in COPD patients with poorer exercise tolerance. Hypoxia and endothelial dysfunction lead to pulmonary vascular dysregulation possibly in part related to nitric oxide related pathways. PURPOSE: To determine if increasing dietary nitrate might influence lung surface area for gas exchange and subsequently impact exercise performance...
March 13, 2018: Nitric Oxide: Biology and Chemistry
Lieselot Decroix, Cajsa Tonoli, Elodie Lespagnol, Constantino Balestra, Amandine Descat, Marie Jose Drittij-Reijnders, Jamie R Blackwell, Wilhelm Stahl, Andrew M Jones, Antje R Weseler, Aalt Bast, Romain Meeusen, Elsa Heyman
INTRODUCTION: During exercise in hypoxia, O2 delivery to brain and muscle is compromised and oxidative stress is elicited. Cocoa flavanols (CF) have antioxidant capacities and can increase blood flow by stimulating endothelial function. We aimed to examine the effects of 7-day CF intake on oxidative stress, nitric oxide production and tissue oxygenation in response to exercise in hypoxia (14.3% O2 ). METHODS: In a randomized, double blind, cross-over study, 14 well-trained male cyclists completed 4 trials: exercise in normoxia or hypoxia, after 7-day CF or placebo intake...
March 15, 2018: Journal of Applied Physiology
Ryan L Sheppard, Joshua M Swift, Aaron Hall, Richard T Mahon
Introduction: Individuals with a known susceptibility to high altitude pulmonary edema (HAPE) demonstrate a reduced ventilation response and increased pulmonary vasoconstriction when exposed to hypoxia. It is unknown whether reduced sensitivity to hypercapnia is correlated with increased incidence and/or severity of HAPE, and while acute exercise at altitude is known to exacerbate symptoms the effect of exercise training on HAPE susceptibility is unclear. Purpose: To determine if chronic intermittent hypercapnia and exercise increases the incidence of HAPE in rats...
2018: Frontiers in Physiology
Yang Yuan, Shan-Shan Pan
BACKGROUND: Late exercise preconditioning (LEP) is confirmed to have a protective effect on acute cardiovascular stress. However, the mechanisms by which mitophagy participates in EP-induced cardioprotection remain unclear. LEP may involve mitophagy mediated by the receptors PARK2 gene-encoded E3 ubiquitin ligase (Parkin) and BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (Bnip3) to scavenge damaged mitochondria. METHODS: Our exercise preconditioning (EP) protocol involved four 10-minute periods of running, separated by 10-minute recovery intervals, plus a period of exhaustive running at 24 hours after EP...
March 9, 2018: Journal of Cardiovascular Pharmacology
Roger Fielding, Linda Riede, James P Lugo, Aouatef Bellamine
Given its pivotal role in fatty acid oxidation and energy metabolism, l-carnitine has been investigated as ergogenic aid for enhancing exercise capacity in the healthy athletic population. Early research indicates its beneficial effects on acute physical performance, such as increased maximum oxygen consumption and higher power output. Later studies point to the positive impact of dietary supplementation with l-carnitine on the recovery process after exercise. It is demonstrated that l-carnitine alleviates muscle injury and reduces markers of cellular damage and free radical formation accompanied by attenuation of muscle soreness...
March 13, 2018: Nutrients
Sinead T J Mcdonagh, Lee J Wylie, Christopher Thompson, Anni Vanhatalo, Andrew M Jones
This article provides an overview of the current literature relating to the efficacy of dietary nitrate (NO3 - ) ingestion in altering aspects of cardiovascular and metabolic health and exercise capacity in healthy and diseased individuals. The consumption of NO3 - -rich vegetables, such as spinach and beetroot, have been variously shown to promote nitric oxide bioavailability, reduce systemic blood pressure, enhance tissue blood flow, modulate muscle O2 utilisation and improve exercise tolerance both in normoxia and in hypoxia, as is commonly observed in a number of disease states...
March 13, 2018: European Journal of Sport Science
Aleksandra Żebrowska, Barbara Hall, Aleksandra Kochańska-Dziurowicz, Grażyna Janikowska
BACKGROUND: An integral part of the treatment of diabetes is physical activity. Scientific reports have shown the beneficial effects of hypoxia and exercise on cardiovascular and metabolic variables in patients with diabetes. OBJECTIVES: The aim of the study was to assess the effect of normobaric hypoxia and exercise on the serum concentrations of proangiogenic factors and glycemia in patients with type 1 diabetes. MATERIAL AND METHODS: A total of 28 adults (aged 30...
February 2018: Advances in Clinical and Experimental Medicine: Official Organ Wroclaw Medical University
Katie A O'Brien, Ross D Pollock, Mike Stroud, Rob J Lambert, Alex Kumar, Robert A Atkinson, David A Green, Ana Anton-Solanas, Lindsay M Edwards, Steve D R Harridge
An insufficient supply of oxygen to the tissues (hypoxia), as is experienced upon high-altitude exposure, elicits physiological acclimatization mechanisms alongside metabolic remodeling. Details of the integrative adaptive processes in response to chronic hypobaric hypoxic exposure remain to be sufficiently investigated. In this small applied field study, subjects (n = 5, male, age 28-54 years) undertook a 40 week Antarctica expedition in the winter months, which included 24 weeks residing above 2500 m...
March 2018: Physiological Reports
Catherine M Ivy, Julia M York, Sabine L Lague, Beverly A Chua, Luis Alza, Kevin G McCracken, William K Milsom, Graham R Scott
Hypoxia at high altitudes constrains O2 supply to support metabolism, thermoregulation in the cold, and exercise. High-altitude natives that somehow overcome this challenge-who live, reproduce, and sometimes perform impressive feats of exercise at high altitudes-are a powerful group in which to study the evolution of physiological systems underlying hypoxia resistance. Here, we sought to determine whether a common pulse oximetry system for rodents (MouseOx Plus) can be used reliably in studies of high-altitude birds by examining the hypoxia responses of the Andean goose...
May 2018: Physiological and Biochemical Zoology: PBZ
Stéphane Doutreleau, Irina Enache, Cristina Pistea, Bernard Geny, Anne Charloux
In this study, we hypothesized that adding CO2 to an inhaled hypoxic gas mixture will limit the rise of pulmonary artery pressure (PAP) induced by a moderate exercise. Eight 20-year-old males performed four constant-load exercise tests on cycle at 40% of maximal oxygen consumption in four conditions: ambient air, normobaric hypoxia (12.5% O2 ), inhaled CO2 (4.5% CO2 ), and combination of hypoxia and inhaled CO2 . Doppler echocardiography was used to measure systolic (s)PAP, cardiac output (CO). Total pulmonary resistance (TPR) was calculated...
March 3, 2018: Pflügers Archiv: European Journal of Physiology
Michael Furian, Sara E Hartmann, Tsogyal D Latshang, Deborah Flueck, Christian Murer, Philipp M Scheiwiller, Batyr Osmonov, Silvia Ulrich, Malcolm Kohler, Marc J Poulin, Konrad E Bloch
BACKGROUND: Effects of hypobaric hypoxia at altitude on exercise performance of lowlanders with chronic obstructive pulmonary disease (COPD) have not been studied in detail. OBJECTIVES: To quantify changes in exercise performance and associated physiologic responses in lowlanders with COPD travelling to moderate altitude. METHODS: A total of 31 COPD patients with a median age (quartiles) of 66 years (59; 69) and FEV1 of 56% predicted (49; 69) living below 800 m performed a constant-load bicycle exercise to exhaustion at 60% of the maximal work rate at 490 m (Zurich) and at an identical work rate at 2,590 m (Davos) in randomized order...
March 2, 2018: Respiration; International Review of Thoracic Diseases
Sílvia Rocha-Rodrigues, Inês O Gonçalves, Jorge Beleza, António Ascensão, José Magalhães
The dysregulation of adipokine secretion owing to adiposopathy can contribute to the pathogenesis of obesity-related disorders. Being that exercise is an advised strategy against obesity-induced adiposopathy, we aimed to analyze the role of physical exercise as a preventive and therapeutic strategy against high-fat diet (HFD)-induced adipokine and ghrelin alterations. Rats were pair-fed the Lieber De Carli standard diet (S, 35 Kcal% fat) or HFD (71 Kcal% fat) over 17 weeks. Animals were assigned into four groups as follows: standard diet sedentary (SS), standard diet voluntary physical activity (SVPA), high-fat diet sedentary (HS), and high-fat diet voluntary physical activity (HVPA)...
February 24, 2018: Journal of Physiology and Biochemistry
Daniel A Keir, Michael Pollock, Piramilan Thuraisingam, Donald H Paterson, George J F Heigenhauser, Harry B Rossiter, John M Kowalchuk
We examined whether slower pulmonary O2 uptake (V̇O2p ) kinetics in hypoxia is a consequence of: a) hypoxia alone (lowered arterial O2 pressure), b) hyperventilation-induced hypocapnia (lowered arterial CO2 pressure), or c) a combination of both. Eleven participants performed 3-5 repetitions of step-changes in cycle ergometer power output from 20W to 80% lactate threshold in the following conditions: i) normoxia (CON; room air); ii) hypoxia (HX, inspired O2  = 12%; lowered end-tidal O2 pressure [PET O2 ] and end-tidal CO2 pressure [PET CO2 ]); iii) hyperventilation (HV; increased PET O2 and lowered PET CO2 ); and iv) normocapnic hypoxia (NC-HX; lowered PET O2 and PET CO2 matched to CON)...
February 22, 2018: Respiratory Physiology & Neurobiology
Alba Camacho-Cardenosa, Marta Camacho-Cardenosa, Martin Burtscher, Ismael Martínez-Guardado, Rafael Timon, Javier Brazo-Sayavera, Guillermo Olcina
A moderate hypoxic stimulus is considered a promising therapeutic modality for several pathological states including obesity. There is scientific evidence suggesting that when hypoxia and physical activity are combined, they could provide benefits for the obese population. The aim of the present study was to investigate if exposure to hypoxia combined with two different protocols of high-intensity interval exercise in overweight/obese women was more effective compared with exercise in normoxia. Study participants included 82 overweight/obese women, who started a 12 week program of 36 sessions, and were randomly divided into four groups: (1) aerobic interval training in hypoxia (AitH; FiO2 = 17...
2018: Frontiers in Physiology
Daria Stypinski, Stephen A McQuarrie, Alexander J B McEwan, Leonard I Wiebe
The objective of this work is to evaluate the potential effect of cardiac stress exercise on the accumulation of [123 I]IAZA, a radiopharmaceutical used to image focal tissue hypoxia, in otherwise normal myocardium in healthy volunteers, and to determine the impact of exercise on [123 I]IAZA pharmacokinetics. The underlying goal is to establish a rational basis and a baseline for studies of focal myocardial hypoxia in cardiac patients using [123 I]IAZA. Three healthy male volunteers ran the 'Bruce' treadmill protocol, a clinically-accepted protocol designed to expose myocardial ischemia in patients...
February 22, 2018: Pharmaceutics
Paul Robach, Joar Hansen, Aurélien Pichon, Anne-Kristine Meinild Lundby, Sune Dandanell, Gunnar Slettaløkken Falch, Daniel Hammarström, Dominik H Pesta, Christoph Siebenmann, Stefanie Keiser, Patricia Kérivel, Jon Elling Whist, Bent R Rønnestad, Carsten Lundby
Live high - train low (LHTL) using hypobaric hypoxia was previously found to improve sea-level endurance performance in well-trained individuals, however confirmatory controlled data in athletes are lacking. Here we test the hypothesis that natural-altitude LHTL improves aerobic performance in cross-country skiers, in conjunction with expansion of total hemoglobin mass (Hbmass , carbon-monoxide rebreathing technique) promoted by accelerated erythropoiesis. Following duplicate baseline measurements at sea level over the course of two weeks, nineteen Norwegian cross-country skiers (three women, sixteen men, age 20±2 yr, maximal oxygen uptake (VO2 max) 69±5 ml...
February 22, 2018: Scandinavian Journal of Medicine & Science in Sports
Qin Yang, Guoyuan Huang, Qianqian Tian, Wei Liu, Xiangdong Sun, Na Li, Shunli Sun, Tang Zhou, Nana Wu, Yuqin Wei, Peijie Chen, Ru Wang
BACKGROUND: "Living High-Training Low" (LHTL) is effective for the improvement of athletic ability; however, little is known about the effect of LHTL on obese individuals. The present study determined whether LHTL would have favorable influence on body composition, rebalance the appetite hormones, and explore the underlying mechanism. METHODS: Adolescents with obesity [body mass index (BMI) >30 kg/m] were randomly assigned to "Living Low-Training Low" (LLTL, n = 19) group that slept in a normobaric normoxia condition and the LHTL (n = 16) group slept in a normobaric hypoxia room (14...
February 2018: Medicine (Baltimore)
John O Onukwufor, Chris M Wood
In the context of the osmorespiratory compromise, hypoxia and temperature have been little studied relative to exercise, and diffusive water flux rates (as assessed by 3 H 2 O efflux) have received almost no attention. We investigated the effects of fish size, hypoxia, exercise and acute temperature increase on diffusive water flux rates and net sodium loss rates in juvenile rainbow trout. Trout weighing 13-50 g were used to determine the effects of fish size under normoxia. Thereafter 25-50 g trout were selected to assess the effects of different hypoxia levels (3...
February 14, 2018: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Kamil Kobak, Monika Kasztura, Magdalena Dziegala, Jacek Bania, Violetta Kapuśniak, Waldemar Banasiak, Piotr Ponikowski, Ewa A Jankowska
There is clinical evidence that patients with heart failure and concomitant iron deficiency have increased skeletal muscle fatigability and impaired exercise tolerance. It was expected that a skeletal muscle cell line subjected to different degrees of iron availability and/or concomitant hypoxia would demonstrate changes in cell morphology and in the expression of atrophy markers. L6G8C5 rat skeletal myocytes were cultured in normoxia or hypoxia at optimal, reduced or increased iron concentrations. Experiments were performed to evaluate the iron content in cells, cell morphology, and the expression of muscle specific atrophy markers [Atrogin1 and muscle‑specific RING‑finger 1 (MuRF1)], a gene associated with the atrophy/hypertrophy balance [mothers against decapentaplegic homolog 4 (SMAD4)] and a muscle class‑III intermediate filament protein (Desmin) at the mRNA and protein level...
February 12, 2018: International Journal of Molecular Medicine
Rebecca D Powell, Donna A Goodenow, A Britton Christmas, Iain H Mckillop, Susan L Evans
Conditions of systemic stress can lead to increased reactive oxygen species production, mitochondrial dysfunction, systemic inflammation, and multiorgan dysfunction. Triphenylphosphonium (TPP+) is a lipophilic cation used to target therapeutics to mitochondria. We sought to determine the effects of TPP+ on mitochondrial integrity. Male rats were anesthetized and TPP+ (5 mg/kg) or vehicle (saline) was administered intravenously 30-minutes after anesthesia initiation and intraperitoneally (20 mg/kg) 60-minutes later...
January 1, 2018: American Surgeon
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