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Roche J, Rasmussen P, Gatterer H, Roveri G, Turner R, van Hall G, Maillard M, Walzl A, Kob M, Strapazzon G, Goetze JP, Schäfer ST, Kammerer T, Nader E, Connes P, Robert M, Mueller T, Feraille E, Siebenmann C. Hypoxia briefly increases diuresis but reduces plasma volume by fluid redistribution in women. Am J Physiol Heart Circ Physiol 2022; 323:H1068-H1079. [PMID: 36269645 PMCID: PMC9678412 DOI: 10.1152/ajpheart.00394.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have recently reported that hypobaric hypoxia (HH) reduces plasma volume (PV) in men by decreasing total circulating plasma protein (TCPP). Here, we investigated whether this applies to women and whether an inflammatory response and/or endothelial glycocalyx shedding could facilitate the TCCP reduction. We further investigated whether acute HH induces a short-lived diuretic response that was overlooked in our recent study, where only 24-h urine volumes were evaluated. In a strictly controlled crossover protocol, 12 women underwent two 4-day sojourns in a hypobaric chamber: one in normoxia (NX) and one in HH equivalent to 3,500-m altitude. PV, urine output, TCPP, and markers for inflammation and glycocalyx shedding were repeatedly measured. Total body water (TBW) was determined pre- and postsojourns by deuterium dilution. PV was reduced after 12 h of HH and thereafter remained 230-330 mL lower than in NX (P < 0.0001). Urine flow was 45% higher in HH than in NX throughout the first 6 h (P = 0.01) but lower during the second half of the first day (P < 0.001). Twenty-four-hour urine volumes (P ≥ 0.37) and TBW (P ≥ 0.14) were not different between the sojourns. TCPP was lower in HH than in NX at the same time points as PV (P < 0.001), but inflammatory or glycocalyx shedding markers were not consistently increased. As in men, and despite initially increased diuresis, HH-induced PV contraction in women is driven by a loss of TCPP and ensuing fluid redistribution, rather than by fluid loss. The mechanism underlying the TCPP reduction remains unclear but does not seem to involve inflammation or glycocalyx shedding.NEW & NOTEWORTHY This study is the first to investigate the mechanisms underlying plasma volume (PV) contraction in response to hypoxia in women while strictly controlling for confounders. PV contraction in women has a similar time course and magnitude as in men and is driven by the same mechanism, namely, oncotically driven redistribution rather than loss of fluid. We further report that hypoxia facilitates an increase in diuresis, that is, however, short-lived and of little relevance for PV regulation.
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Affiliation(s)
- Johanna Roche
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | | | - Hannes Gatterer
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Giulia Roveri
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Rachel Turner
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Gerrit van Hall
- 3Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark,4Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,5Clinical Metabolomics Core Facility, Rigshospitalet, University of Copenhagen, Denmark
| | - Marc Maillard
- 6Service of Nephrology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Anna Walzl
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany
| | - Michael Kob
- 8Division of Clinical Nutrition, Bolzano Regional Hospital, Bolzano, Italy
| | - Giacomo Strapazzon
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Jens Peter Goetze
- 3Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Simon Thomas Schäfer
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany
| | - Tobias Kammerer
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany,9Department for Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Elie Nader
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Philippe Connes
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Mélanie Robert
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Thomas Mueller
- 11Department of Clinical Pathology, Hospital of Bolzano, Bolzano, Italy,12Department of Laboratory Medicine, Hospital Voecklabruck, Voecklabruck, Austria
| | - Eric Feraille
- 13National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland,14Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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2
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Oberholzer L, Bonne TC, Breenfeldt Andersen A, Bejder J, Højgaard Christensen R, Baastrup Nordsborg N, Lundby C. Reproducibility of the CO rebreathing technique with a lower CO dose and a shorter rebreathing duration at sea level and at 2320 m of altitude. Scandinavian Journal of Clinical and Laboratory Investigation 2020; 80:590-599. [PMID: 32955368 DOI: 10.1080/00365513.2020.1818282] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Total hemoglobin mass (Hbmass) is routinely assessed in studies by the carbon monoxide (CO) rebreathing. Its clinical application is often hindered due to the consequent rise in carboxyhemoglobin (%HbCO) and the concern of CO toxicity. We tested the reproducibility of the CO rebreathing with a CO dose of 0.5 mL/kg body mass (CO0.5) compared to 1.5 mL/kg (CO1.5) and when shortening the CO rebreathing protocol. Therefore, CO rebreathing was performed 1×/day in eight healthy individuals on four consecutive days. On each day, either CO0.5 (CO0.5-1 and CO0.5-2) or CO1.5 (CO1.5-1 and CO1.5-2) was administered. Venous blood samples to determine %HbCO and quantify Hbmass were obtained prior to, and at 6 (T6), 8 (T8) and 10 min (T10) of CO rebreathing. This protocol was tested at sea level and at 2320 m to investigate the altitude-related measurement error. At sea level, the mean difference (95% limits of agreement) in Hbmass between CO0.5-1 and CO0.5-2 was 26 g (-26; 79 g) and between CO1.5-1 and CO1.5-2, it was 17 g (-18; 52 g). The respective typical error (TE) corresponded to 2.4% (CO0.5) and 1.5% (CO1.5), while it was 6.5% and 3.0% at 2320 m. With CO0.5, shortening the CO rebreathing resulted in a TE for Hbmass of 4.4% (T8 vs. T10) and 14.1% (T6 vs T10) and with CO1.5, TE was 1.6% and 5.8%. In conclusion, the CO dose and rebreathing time for the CO rebreathing procedure can be decreased at the cost of a measurement error ranging from 1.5-14.1%.
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Affiliation(s)
- Laura Oberholzer
- Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Christian Bonne
- Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Jacob Bejder
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Carsten Lundby
- Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Innland University of Applied Sciences, Lillehammer, Norway
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3
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Xia W, Huang ZJ, Guo ZL, Feng YW, Zhang CY, He GY, Tang AZ. Plasma volume, cell volume, total blood volume and F factor in the tree shrew. PLoS One 2020; 15:e0234835. [PMID: 32881864 PMCID: PMC7470369 DOI: 10.1371/journal.pone.0234835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/18/2020] [Indexed: 12/21/2022] Open
Abstract
In this study, the physiological values of volumes of plasma, cells, total blood and the F blood factors were identified in 24 adult tree shrews (Tupaia belangeri; 12 male and 12 female; average BW of 123.9±19.19 g). The two-compartment model method of Evans Blue dye was used to obtain the plasma volume and the venous hematocrit was measured by microhematocrit method. To establish the relationship between body weight (BW) and blood volume of tree shrews, We performed linear fitting for these two datasets. Results were analyzed according to gender and weight (<120g vs.>120g). Statistical significance was assessed using the unpaired student t test and one-way ANOVA. The average volumes per 100g body weight of plasma, red blood cell (RBC) and total blood were 5.42±0.543, 3.24±0.445, and 8.66±0.680ml respectively. The mean body hematocrit, cardiac hematocrit, jugular vein hematocrit, femoral vein hematocrit, and tail vein hematocrit was 37.43±4.096, 39.72±3.219, 43.04±4.717, 40.84±3.041, and 38.71±3.442% respectively. The F cardiac was 0.94±0.072, F jugular vein 0.88±0.118, F femoral vein 0.92±0.111, and the F tail vein 0.97±0.117. Blood volume (ml) was 85.89103×BW (kg). This is the first study to provide the parameters of plasma volume, cell volume, total blood volume and F factor and a baseline for future research on blood physiology of tree shrews.
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Affiliation(s)
- Wei Xia
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
| | - Zong-jian Huang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
| | - Zhao-liang Guo
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
| | - Yi-wei Feng
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
| | - Chao-yin Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
| | - Guang-yao He
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
- * E-mail: (GH); (AT)
| | - An-zhou Tang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, China
- * E-mail: (GH); (AT)
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4
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Swenson KE, Berger MM, Sareban M, Macholz F, Schmidt P, Schiefer LM, Mairbäurl H, Swenson ER. Rapid Ascent to 4559 m Is Associated with Increased Plasma Components of the Vascular Endothelial Glycocalyx and May Be Associated with Acute Mountain Sickness. High Alt Med Biol 2020; 21:176-183. [DOI: 10.1089/ham.2019.0081] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Kai Erik Swenson
- Division of Pulmonary and Critical Care Medicine, Stanford University, Palo Alto, California, USA
| | - Marc Moritz Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Essen, Germany
| | - Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
- Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Franziska Macholz
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Peter Schmidt
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Lisa Maria Schiefer
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Heimo Mairbäurl
- Division of Sports Medicine, Department of Internal Medicine VII, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany
| | - Erik Richard Swenson
- Pulmonary, Critical Care and Sleep Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, Washington, USA
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5
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Richalet JP, Marchant D, Macarlupu JL, Voituron N. Modeling the Evans Blue Dilution Method for the Measurement of Plasma Volume in Small Animals: A New Optimized Method. Ann Biomed Eng 2018; 46:2189-2195. [PMID: 30136152 DOI: 10.1007/s10439-018-02114-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/10/2018] [Indexed: 11/28/2022]
Abstract
The measurement of plasma volume (Vp) in humans and animals is frequently performed by the Evans blue dye dilution method. However, after injection of Evans blue into the circulation, no steady state is observed because of delayed mixing and progressive leakage of dye out of vascular space. Various methods of calculation have been proposed, either with a single blood sampling 5-10 min after dye injection (Single point method), or with extrapolation at time zero of a logarithmic decay (Log linear method). We propose a method based on a two-compartment hypothesis taking into account the initial mixing and the leakage phase in the time course of dye concentration. Nineteen Sprague-Dawley rats were studied in various conditions and blood sampling was performed before and 2, 4 and 6 min after injection of 200 μg Evans blue. A mathematical model was designed to describe the two-compartment hypothesis and allowed the calculation of Vp and Kout (rate of disappearance of dye from vascular space). A Bland and Altman representation evidenced an overestimation of Vp with previous methods and the great dispersion of results with the single point method, especially when using the 6 min point. Calculation of Kout revealed more accurate with the model than the Log linear method, especially when the mixing rate is slow. We suggest using the two-compartment model to measure Vp with Evans blue technique in rats. This method also allows precise evaluation of the rate of dye leakage, which could be a good marker of vascular permeability to albumin.
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Affiliation(s)
- Jean-Paul Richalet
- Laboratoire "Hypoxie et poumon" EA2363, Université Paris 13, 74 rue Marcel Cachin, 93017, Bobigny Cedex, France. .,Laboratoire d'excellence, GReX, Paris, France.
| | - Dominique Marchant
- Laboratoire "Hypoxie et poumon" EA2363, Université Paris 13, 74 rue Marcel Cachin, 93017, Bobigny Cedex, France
| | - Jose-Luis Macarlupu
- Laboratorio de Fisiologia Comparada, Universidad Cayetano Heredia, Lima, Peru
| | - Nicolas Voituron
- Laboratoire "Hypoxie et poumon" EA2363, Université Paris 13, 74 rue Marcel Cachin, 93017, Bobigny Cedex, France.,Laboratoire d'excellence, GReX, Paris, France
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6
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Siebenmann C, Robach P, Lundby C. Regulation of blood volume in lowlanders exposed to high altitude. J Appl Physiol (1985) 2017; 123:957-966. [PMID: 28572493 DOI: 10.1152/japplphysiol.00118.2017] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/18/2017] [Accepted: 05/31/2017] [Indexed: 12/21/2022] Open
Abstract
Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2 content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initially, hemoconcentration is exclusively related to a reduction in plasma volume (PV), whereas after several weeks a progressive expansion in total red blood cell volume (RCV) contributes, although often to a modest extent. Since the decrease in PV is more rapid and usually more pronounced than the expansion in RCV, at least during the first weeks of exposure, a reduction in circulating blood volume is common at HA. Although the regulation of hematological responses to HA has been investigated for decades, it remains incompletely understood. This is not only related to the large number of mechanisms that could be involved and the complexity of their interplay but also to the difficulty of conducting comprehensive experiments in the often secluded HA environment. In this review, we present our understanding of the kinetics, the mechanisms and the physiological relevance of the HA-induced reduction in PV and expansion in RCV.
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Affiliation(s)
- Christoph Siebenmann
- The Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; and
| | - Paul Robach
- National School for Mountain Sports, Site of the National School for Skiing and Mountaineering (ENSA), Chamonix, France
| | - Carsten Lundby
- The Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; and
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7
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Keiser S, Meinild-Lundby AK, Steiner T, Trösch S, Rauber S, Krafft A, Burkhardt T, Hilty MP, Siebenmann C, Wehrlin JP, Lundby C. Detection of blood volumes and haemoglobin mass by means of CO re-breathing and indocyanine green and sodium fluorescein injections. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:164-174. [PMID: 28276723 DOI: 10.1080/00365513.2016.1271908] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The main aim of the present study was to quantify the magnitude of differences introduced when estimating a given blood volume compartment (e.g. plasma volume) through the direct determination of another compartment (e.g. red cell volume) by multiplication of venous haematocrit and/or haemoglobin concentration. However, since whole body haematocrit is higher than venous haematocrit such an approach might comprise certain errors. To test this experimentally, four different methods for detecting blood volumes and haemoglobin mass (Hbmass) were compared, namely the carbon monoxide (CO) re-breathing (for Hbmass), the indocyanine green (ICG; for plasma volume [PV]) and the sodium fluorescein (SoF; for red blood cell volume [RBCV]) methods. No difference between ICG and CO re-breathing derived PV could be established when a whole body/venous haematocrit correction factor of 0.91 was applied (p = 0.11, r = 0.43, mean difference -340 ± 612 mL). In contrast, when comparing RBCV derived by the CO re-breathing and the SoF method, the SoF method revealed lower RBCV values as compared to the CO re-breathing method (p < 0.05, r = 0.95, mean difference -728 ± 184 mL). However, compared to the ICG and the SoF methods, the typical error (%TE) and hence reliability of the CO re-breathing method was lower for all measured parameters. Therefore, estimating blood volume compartments by the direct assessment of another compartment can be considered a suitable approach. The CO re-breathing method proved accurate in determining the induced phlebotomy and is at the same time judged easier to perform than any of the other methods.
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Affiliation(s)
- Stefanie Keiser
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Anne-Kristine Meinild-Lundby
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Thomas Steiner
- b Swiss Federal Institute of Sports , Magglingen , Switzerland
| | - Severin Trösch
- b Swiss Federal Institute of Sports , Magglingen , Switzerland
| | - Sven Rauber
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
| | - Alexander Krafft
- c Foeto-Maternal Haematology Group, Department of Obstetrics , University Hospital of Zurich , Zurich , Switzerland
| | - Tilo Burkhardt
- c Foeto-Maternal Haematology Group, Department of Obstetrics , University Hospital of Zurich , Zurich , Switzerland
| | | | - Christoph Siebenmann
- e Department of Environmental Physiology, School of Technology and Health , Royal Institute of Technology , Solna , Sweden
| | | | - Carsten Lundby
- a Zurich Center for Integrative Human Physiology , Institute of Physiology, University of Zurich , Zurich , Switzerland
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8
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Stembridge M, Ainslie PN, Shave R. Mechanisms underlying reductions in stroke volume at rest and during exercise at high altitude. Eur J Sport Sci 2015; 16:577-84. [DOI: 10.1080/17461391.2015.1071876] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Ryan BJ, Wachsmuth NB, Schmidt WF, Byrnes WC, Julian CG, Lovering AT, Subudhi AW, Roach RC. AltitudeOmics: rapid hemoglobin mass alterations with early acclimatization to and de-acclimatization from 5260 m in healthy humans. PLoS One 2014; 9:e108788. [PMID: 25271637 PMCID: PMC4182755 DOI: 10.1371/journal.pone.0108788] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 08/26/2014] [Indexed: 01/09/2023] Open
Abstract
It is classically thought that increases in hemoglobin mass (Hbmass) take several weeks to develop upon ascent to high altitude and are lost gradually following descent. However, the early time course of these erythropoietic adaptations has not been thoroughly investigated and data are lacking at elevations greater than 5000 m, where the hypoxic stimulus is dramatically increased. As part of the AltitudeOmics project, we examined Hbmass in healthy men and women at sea level (SL) and 5260 m following 1, 7, and 16 days of high altitude exposure (ALT1/ALT7/ALT16). Subjects were also studied upon return to 5260 m following descent to 1525 m for either 7 or 21 days. Compared to SL, absolute Hbmass was not different at ALT1 but increased by 3.7±5.8% (mean ± SD; n = 20; p<0.01) at ALT7 and 7.6±6.6% (n = 21; p<0.001) at ALT16. Following descent to 1525 m, Hbmass was reduced compared to ALT16 (−6.0±3.7%; n = 20; p = 0.001) and not different compared to SL, with no difference in the loss in Hbmass between groups that descended for 7 (−6.3±3.0%; n = 13) versus 21 days (−5.7±5.0; n = 7). The loss in Hbmass following 7 days at 1525 m was correlated with an increase in serum ferritin (r = −0.64; n = 13; p<0.05), suggesting increased red blood cell destruction. Our novel findings demonstrate that Hbmass increases within 7 days of ascent to 5260 m but that the altitude-induced Hbmass adaptation is lost within 7 days of descent to 1525 m. The rapid time course of these adaptations contrasts with the classical dogma, suggesting the need to further examine mechanisms responsible for Hbmass adaptations in response to severe hypoxia.
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Affiliation(s)
- Benjamin J. Ryan
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
- * E-mail:
| | - Nadine B. Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Walter F. Schmidt
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - William C. Byrnes
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Colleen G. Julian
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Andrew T. Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Andrew W. Subudhi
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado, United States of America
| | - Robert C. Roach
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
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10
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Hematy Y, Setorki M, Razavi A, Doudi M. Effect of altitude on some blood factors and its stability after leaving the altitude. Pak J Biol Sci 2014; 17:1052-1057. [PMID: 26031025 DOI: 10.3923/pjbs.2014.1052.1057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The underlying mechanisms of altitude training are still a matter of controversial discussion. The aim of this study was to compare the hemoglobin concentration, red blood cell count and volume between normal and high altitude situations and their persistence after returning back from higher altitudes. The study population included male students of Ardal Branch, Islamic Azad University. Twelve apparently healthy individual with high level of physical activity, mean age of 22.6 ± 1.50 years were selected through purposive and available sampling method. In this study, blood samples were collected at different time and altitudes in order to compare the changes of Red Blood Cell (RBC), Mean Cell Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC) and Mean Cell Volume (MCV). The first blood sampling was conducted at the altitude of 1830 m. The subsequent blood samplings were conducted 48 and 72 h after reaching the altitude of 4000 m and 24, 48 and 72 h after returning back to the altitude of 1830 m. The statistical method used in this study was repeated measurement ANOVA. Red Blood Cell (RBC) changes between onset of climbing to 1830 m and 24, 48 and 2 h after sojourn at 1830 m height (after returning from 4000 m altitude) was significant. Mean Cell Hemoglobin (MCH) showed no significant change in any of the altitudes. MCHC changes between onset of moving toward altitude 1830 meters and 24, 48 and 72 h after sojourn at 1830 m height (after returning from 4000 m altitude) was also significant in addition, MCHC showed a significant difference between 24 h staying at 1830 m altitude with 48 and 72 h staying at 4000 m altitude. Mean Cell Volume (MCV) showed no significant difference between 48 and 72 h staying at 4000 m altitude and also between 24, 48 and 72 h staying at 1830 m altitude; however, there was a significant difference between onset of moving toward 1830 m altitude with 24, 48 and 72 h staying at 1830 m altitude and also 48 and 72 h staying at 4000 m altitude. The results showed that being in altitude has significant effect on RBC and MCHC.
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11
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Chapman RF, Karlsen T, Resaland GK, Ge RL, Harber MP, Witkowski S, Stray-Gundersen J, Levine BD. Defining the “dose” of altitude training: how high to live for optimal sea level performance enhancement. J Appl Physiol (1985) 2014; 116:595-603. [DOI: 10.1152/japplphysiol.00634.2013] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic living at altitudes of ∼2,500 m causes consistent hematological acclimatization in most, but not all, groups of athletes; however, responses of erythropoietin (EPO) and red cell mass to a given altitude show substantial individual variability. We hypothesized that athletes living at higher altitudes would experience greater improvements in sea level performance, secondary to greater hematological acclimatization, compared with athletes living at lower altitudes. After 4 wk of group sea level training and testing, 48 collegiate distance runners (32 men, 16 women) were randomly assigned to one of four living altitudes (1,780, 2,085, 2,454, or 2,800 m). All athletes trained together daily at a common altitude from 1,250–3,000 m following a modified live high-train low model. Subjects completed hematological, metabolic, and performance measures at sea level, before and after altitude training; EPO was assessed at various time points while at altitude. On return from altitude, 3,000-m time trial performance was significantly improved in groups living at the middle two altitudes (2,085 and 2,454 m), but not in groups living at 1,780 and 2,800 m. EPO was significantly higher in all groups at 24 and 48 h, but returned to sea level baseline after 72 h in the 1,780-m group. Erythrocyte volume was significantly higher within all groups after return from altitude and was not different between groups. These data suggest that, when completing a 4-wk altitude camp following the live high-train low model, there is a target altitude between 2,000 and 2,500 m that produces an optimal acclimatization response for sea level performance.
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Affiliation(s)
| | - Trine Karlsen
- Norwegian University of Sport and Physical Education, Oslo, Norway
| | - Geir K. Resaland
- Norwegian University of Sport and Physical Education, Oslo, Norway
| | - R.-L. Ge
- Research Center for High Altitude Medicine, Qinghai University, Xining, Qinghai, China; and
| | - Matthew P. Harber
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sarah Witkowski
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, The University of Texas Southwestern Medical Center, Dallas, Texas
| | | | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, The University of Texas Southwestern Medical Center, Dallas, Texas
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Recommendations for resuscitation after ascent to high altitude and in aircrafts. Int J Cardiol 2013; 167:1703-11. [DOI: 10.1016/j.ijcard.2012.11.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 11/11/2012] [Indexed: 12/31/2022]
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13
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Artificial gravity training reduces bed rest-induced cardiovascular deconditioning. Eur J Appl Physiol 2011; 112:605-16. [PMID: 21626041 DOI: 10.1007/s00421-011-2005-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
We studied 15 men (8 treatment, 7 control) before and after 21 days of 6º head-down tilt to determine whether daily, 1-h exposures to 1.0 G(z) (at the heart) artificial gravity (AG) would prevent bed rest-induced cardiovascular deconditioning. Testing included echocardiographic analysis of cardiac function, plasma volume (PV), aerobic power (VO(2)pk) and cardiovascular and neuroendocrine responses to 80º head-up tilt (HUT). Data collected during HUT were ECG, stroke volume (SV), blood pressure (BP) and blood for catecholamines and vasoactive hormones. Heart rate (HR), cardiac output (CO), total peripheral resistance, and spectral power of BP and HR were calculated. Bed rest decreased PV, supine and HUT SV, and indices of cardiac function in both groups. Although PV was decreased in control and AG after bed rest, AG attenuated the decrease in orthostatic tolerance [pre- to post-bed rest change; control: -11.8 ± 2.0, AG: -6.0 ± 2.8 min (p = 0.012)] and VO(2)pk [pre- to post-bed rest change; control: -0.39 ± 0.11, AG: -0.17 ± 0.06 L/min (p = 0.041)]. AG prevented increases in pre-tilt levels of plasma renin activity [pre- to post-bed rest change; control: 1.53 ± 0.23, AG: -0.07 ± 0.34 ng/mL/h (p = 0.001)] and angiotensin II [pre- to post-bed rest change; control: 3.00 ± 1.04, AG: -0.63 ± 0.81 pg/mL (p = 0.009)] and increased HUT aldosterone [post-bed rest; control: 107 ± 30 pg/mL, AG: 229 ± 68 pg/mL (p = 0.045)] and norepinephrine [post-bed rest; control: 453 ± 107, AG: 732 ± 131 pg/mL (p = 0.003)]. We conclude that AG can mitigate some aspects of bed rest-induced cardiovascular deconditioning, including orthostatic intolerance and aerobic power. Mechanisms of improvement were not cardiac-mediated, but likely through improved sympathetic responsiveness to orthostatic stress.
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Steiner T, Wehrlin JP. Comparability of haemoglobin mass measured with different carbon monoxide-based rebreathing procedures and calculations. Scandinavian Journal of Clinical and Laboratory Investigation 2010; 71:19-29. [PMID: 21091271 DOI: 10.3109/00365513.2010.534174] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Measurements of haemoglobin mass (Hb(mass)) with the carbon monoxide (CO) rebreathing method provide valuable information in the field of sports medicine, and have markedly increased during the last decade. However, several different approaches (as a combination of the rebreathing procedure and subsequent calculations) for measuring Hb(mass) are used, and routine measurements have indicated that the Hb(mass) differs substantially among various approaches. Therefore, the aim of this study was to compare the Hb(mass) of the seven most commonly used approaches, and then to provide conversion factors for an improved comparability of Hb(mass) measured with the different approaches. METHODS Seventeen subjects (healthy, recreationally active, male, age 27.1 ± 1.8 y) completed 3 CO-rebreathing measurements in randomized order. One was based on the 12-min original procedure (CO(original)), and two were based on the 2-min optimized procedure (CO(new)). From these measurements Hb(mass) for seven approaches (CO(originalA-E); CO(newA-B)) was calculated. RESULTS Hb(mass) estimations differed among these approaches (p < 0.01). Hb(mass) averaged 960 ± 133 g (CO(newB)), 981 ± 136 g (CO(newA)), 989 ± 130 g (CO(originalE)), 993 ± 126 g (CO(originalA,D)), 1030 ± 130 g (CO(originalB)), and 1053 ± 133 g (CO(originalC)). Procedural variations had a minor influence on measured Hb(mass). CONCLUSIONS The relevant discrepancies between the CO-rebreathing approaches originate mainly from different underlying calculations for Hb(mass). Provided Hb(mass) enabled the development of conversion factors to compare average Hb(mass) values measured with different CO-rebreathing approaches. These factors can be used to develop reasonable Hb(mass) reference ranges for both clinical and athletic purposes.
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Affiliation(s)
- Thomas Steiner
- Section for Elite Sports, Swiss Federal Institute of Sports, Magglingen, Switzerland.
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15
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Abstract
Altitude exposure is associated with major changes in cardiovascular function. The initial cardiovascular response to altitude is characterized by an increase in cardiac output with tachycardia, no change in stroke volume, whereas blood pressure may temporarily be slightly increased. After a few days of acclimatization, cardiac output returns to normal, but heart rate remains increased, so that stroke volume is decreased. Pulmonary artery pressure increases without change in pulmonary artery wedge pressure. This pattern is essentially unchanged with prolonged or lifelong altitude sojourns. Ventricular function is maintained, with initially increased, then preserved or slightly depressed indices of systolic function, and an altered diastolic filling pattern. Filling pressures of the heart remain unchanged. Exercise in acute as well as in chronic high-altitude exposure is associated with a brisk increase in pulmonary artery pressure. The relationships between workload, cardiac output, and oxygen uptake are preserved in all circumstances, but there is a decrease in maximal oxygen consumption, which is accompanied by a decrease in maximal cardiac output. The decrease in maximal cardiac output is minimal in acute hypoxia but becomes more pronounced with acclimatization. This is not explained by hypovolemia, acid-bases status, increased viscosity on polycythemia, autonomic nervous system changes, or depressed systolic function. Maximal oxygen uptake at high altitudes has been modeled to be determined by the matching of convective and diffusional oxygen transport systems at a lower maximal cardiac output. However, there has been recent suggestion that 10% to 25% of the loss in aerobic exercise capacity at high altitudes can be restored by specific pulmonary vasodilating interventions. Whether this is explained by an improved maximum flow output by an unloaded right ventricle remains to be confirmed. Altitude exposure carries no identified risk of myocardial ischemia in healthy subjects but has to be considered as a potential stress in patients with previous cardiovascular conditions.
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Yao J, Maslov K, Hu S, Wang LV. Evans blue dye-enhanced capillary-resolution photoacoustic microscopy in vivo. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:054049. [PMID: 19895150 PMCID: PMC2782364 DOI: 10.1117/1.3251044] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Complete and continuous imaging of microvascular networks is crucial for a wide variety of biomedical applications. Photoacoustic tomography can provide high resolution microvascular imaging using hemoglobin within red blood cells (RBCs) as an endogenic contrast agent. However, intermittent RBC flow in capillaries results in discontinuous and fragmentary capillary images. To overcome this problem, we use Evans blue (EB) dye as a contrast agent for in vivo photoacoustic imaging. EB has strong optical absorption and distributes uniformly in the blood stream by chemically binding to albumin. With the help of EB, complete and continuous microvascular networks--especially capillaries--are imaged. The diffusion dynamics of EB leaving the blood stream and the clearance dynamics of the EB-albumin complex are also quantitatively investigated.
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Affiliation(s)
- Junjie Yao
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, USA
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17
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Gore CJ, Rodríguez FA, Truijens MJ, Townsend NE, Stray-Gundersen J, Levine BD. Increased serum erythropoietin but not red cell production after 4 wk of intermittent hypobaric hypoxia (4,000-5,500 m). J Appl Physiol (1985) 2006; 101:1386-93. [PMID: 16794028 DOI: 10.1152/japplphysiol.00342.2006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study tested the hypothesis that athletes exposed to 4 wk of intermittent hypobaric hypoxia exposure (3 h/day, 5 days/wk at 4,000-5,500 m) or double-blind placebo increase their red blood cell volume (RCV) and hemoglobin mass (Hbmass) secondary to an increase in erythropoietin (EPO). Twenty-three collegiate level athletes were measured before (Pre) and after (Post) the intervention for RCV via Evans blue (EB) dye and in duplicate for Hbmass using CO rebreathing. Hematological indexes including EPO, soluble transferrin receptor, and reticulocyte parameters were measured on 8-10 occasions spanning the intervention. The subjects were randomly divided among hypobaric hypoxia (Hypo, n = 11) and normoxic (Norm, n = 12) groups. Apart from doubling EPO concentration 3 h after hypoxia there was no increase in any of the measures for either Hypo or Norm groups. The mean change in RCV from Pre to Post for the Hypo group was 2.3% (95% confidence limits = -4.8 to 9.5%) and for the Norm group was -0.2% (-5.7 to 5.3%). The corresponding changes in Hbmass were 1.0% (-1.3 to 3.3%) for Hypo and -0.3% (-2.6 to 3.1%) for Norm. There was good agreement between blood volume (BV) from EB and CO: EB BV = 1.03 x CO BV + 142, r2 = 0.85, P < 0.0001. Overall, evidence from four independent techniques (RCV, Hbmass, reticulocyte parameters, and soluble transferrin receptor) suggests that intermittent hypobaric hypoxia exposure did not accelerate erythropoiesis despite the increase in serum EPO.
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18
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Bauer A, Demetz F, Bruegger D, Schmoelz M, Schroepfer S, Martignoni A, Baschnegger H, Hoelzl J, Thiel M, Choukér A, Peter K, Gamble J, Christ F. Effect of high altitude and exercise on microvascular parameters in acclimatized subjects. Clin Sci (Lond) 2006; 110:207-15. [PMID: 16194151 DOI: 10.1042/cs20050217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The role of microvascular fluid shifts in the adaptation to hypobaric hypoxia and its contribution to the pathophysiology of AMS (acute mountain sickness) is unresolved. In a systematic prospective study, we investigated the effects of hypobaric hypoxia and physical exercise alone, and in combination, on microvascular fluid exchange and related factors. We used computer-assisted VCP (venous congestion plethysmography) on the calves of ten altitude-acclimatized volunteers. We investigated the effects of: (i) actively climbing to an altitude of 3196 m, (ii) airlifting these subjects to the same altitude, and (iii) exercise at low altitude. CFC (capillary filtration capacity), Pvi (isovolumetric venous pressure) and Qa (calf blood flow) were assessed before and after each procedure and then repeated after an overnight rest. Measurements of CFC showed no evidence of increased microvascular permeability after any of the procedures. Pvi was significantly decreased (P<0.001) from 20.3±4.4 to 8.9±4.3 mmHg after active ascent, and was still significantly lower (P=0.009) after overnight rest at high altitude (13.6±5.9 mmHg). No such changes were observed after the passive ascent (16.7±4.0 mmHg at baseline; 17.3±4.5 mmHg after passive ascent; and 19.9±5.3 mmHg after overnight rest) or after exercise at low altitude. After the active ascent, Qa was significantly increased. We also found a significant correlation between Qa, Pvi and the number of circulating white blood cells. In conclusion, we found evidence to support the hypothesis that increased microvascular permeability associated with AMS does not occur in acclimatized subjects. We also observed that the microvascular equilibrium pressure (Pvi) fell in inverse relation to the increase in Qa, especially in hypoxic exercise. We hypothesize that this inverse relationship reflects the haemodynamic changes at the microvascular interface, possibly attributable to the flow-induced increases in endothelial surface shear forces.
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Affiliation(s)
- Andreas Bauer
- Clinic for Anaesthesiology, Ludwig-Maximilians University Munich, Marchioninistr. 15, 81377 Munich, Germany.
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Robach P, Schmitt L, Brugniaux JV, Roels B, Millet G, Hellard P, Nicolet G, Duvallet A, Fouillot JP, Moutereau S, Lasne F, Pialoux V, Olsen NV, Richalet JP. Living high–training low: effect on erythropoiesis and aerobic performance in highly-trained swimmers. Eur J Appl Physiol 2005; 96:423-33. [PMID: 16328191 DOI: 10.1007/s00421-005-0089-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2005] [Indexed: 12/01/2022]
Abstract
The "living high-training low" model (LHTL), i.e., training in normoxia but sleeping/living in hypoxia, is designed to improve the athletes performance. However, LHTL efficacy still remains controversial and also little is known about the duration of its potential benefit. This study tested whether LHTL enhances aerobic performance in athletes, and if any positive effect may last for up to 2 weeks after LHTL intervention. Eighteen swimmers trained for 13 days at 1,200 m while sleeping/living at 1,200 m in ambient air (control, n=9) or in hypoxic rooms (LHTL, n=9, 5 days at simulated altitude of 2,500 m followed by 8 days at simulated altitude of 3,000 m, 16 h day(-1)). Measures were done before 1-2 days (POST-1) and 2 weeks after intervention (POST-15). Aerobic performance was assessed from two swimming trials, exploring .VO(2max) and endurance performance (2,000-m time trial), respectively. Reticulocyte, serum EPO and soluble transferrin receptor responses were not altered by LHTL, whereas reticulocytes decreased in controls. In POST-1 (vs. before): red blood cell volume increased in LHTL only (+8.5%, P=0.03), .VO(2max) tended to increase more in LHTL (+8.1%, P=0.09) than in controls (+2.5%, P=0.21) without any difference between groups (P=0.42) and 2,000-m performance was unchanged with LHTL. In POST-15, both performance and hematological parameters were similar to initial levels. Our results indicate that LHTL may stimulate red cell production, without any concurrent amelioration of aerobic performance. The absence of any prolonged benefit after LHTL suggests that this LHTL model cannot be recommended for long-term purposes.
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Affiliation(s)
- Paul Robach
- Ecole Nationale de Ski et d'Alpinisme, 35 route du Bouchet, 74401 Chamonix, France
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20
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Brugniaux JV, Schmitt L, Robach P, Nicolet G, Fouillot JP, Moutereau S, Lasne F, Pialoux V, Saas P, Chorvot MC, Cornolo J, Olsen NV, Richalet JP. Eighteen days of "living high, training low" stimulate erythropoiesis and enhance aerobic performance in elite middle-distance runners. J Appl Physiol (1985) 2005; 100:203-11. [PMID: 16179396 DOI: 10.1152/japplphysiol.00808.2005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The efficiency of "living high, training low" (LHTL) remains controversial, despite its wide utilization. This study aimed to verify whether maximal and/or submaximal aerobic performance were modified by LHTL and whether these effects persist for 15 days after returning to normoxia. Last, we tried to elucidate whether the mechanisms involved were only related to changes in oxygen-carrying capacity. Eleven elite middle-distance runners were tested before (Pre), at the end (Post1), and 15 days after the end (Post2) of an 18-day LHTL session. Hypoxic group (LHTL, n = 5) spent 14 h/day in hypoxia (6 nights at 2,500 m and 12 nights at 3,000 m), whereas the control group (CON, n = 6) slept in normoxia (1,200 m). Both LHTL and CON trained at 1,200 m. Maximal oxygen uptake and maximal aerobic power were improved at Post1 and Post2 for LHTL only (+7.1 and +3.4% for maximal oxygen uptake, +8.4 and +4.7% for maximal aerobic power, respectively). Similarly oxygen uptake and ventilation at ventilatory threshold increased in LHTL only (+18.1 and +12.2% at Post1, +15.9 and +15.4% at Post2, respectively). Heart rate during a 10-min run at 19.5 km/h decreased for LHTL at Post2 (-4.4%). Despite the stimulation of erythropoiesis in LHTL shown by the 27.4% increase in serum transferrin receptor and the 10.1% increase in total hemoglobin mass, red cell volume was not significantly increased at Post1 (+9.2%, not significant). Therefore, both maximal and submaximal aerobic performance in elite runners were increased by LHTL mainly linked to an improvement in oxygen transport in early return to normoxia and probably to other process at Post2.
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Affiliation(s)
- Julien V Brugniaux
- Université Paris 13, Laboratoire Réponses cellulaires et fonctionnelles à l'hypoxie, Bobigny, France.
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21
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Gore CJ, Hopkins WG, Burge CM. Errors of measurement for blood volume parameters: a meta-analysis. J Appl Physiol (1985) 2005; 99:1745-58. [PMID: 15976358 DOI: 10.1152/japplphysiol.00505.2005] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The volume of red blood cells (V(RBC)) is used routinely in the diagnostic workup of polycythemia, in assessing the efficacy of erythropoietin administration, and to study factors affecting oxygen transport. However, errors of various methods of measurement of V(RBC) and related parameters are not well characterized. We meta-analyzed 346 estimates of error of measurement of V(RBC) for techniques based on Evans blue (V(RBC,Evans)), 51chromium-labeled red blood cells (V(RBC,51Cr)), and carbon monoxide (CO) rebreathing (V(RBC,CO)), as well as hemoglobin mass with the carbon-monoxide method (M(Hb,CO)), in athletes and active and inactive subjects undergoing various experimental and control treatments lasting minutes to months. Subject characteristics and experimental treatments had little effect on error of measurement, but measures with the smallest error showed some increase in error with increasing time between trials. Adjusted to 1 day between trials and expressed as coefficients of variation, mean errors for M(Hb,CO) (2.2%; 90% confidence interval 1.4-3.5%) and V(RBC,51Cr) (2.8%; 2.4-3.2%) were much less than those for V(RBC,Evans) (6.7%; 4.9-9.4%) and V(RBC,CO) (6.7%; 3.4-14%). Most of the error of V(RBC,Evans) was due to error in measurement of volume of plasma via Evans blue dye (6.0%; 4.5-7.8%), which is the basis of V(RBC,Evans). Most of the error in V(RBC,CO) was due to estimates from laboratories with a relatively large error in M(Hb,CO), the basis of V(RBC,CO). V(RBC,51Cr) and M(Hb,CO) are the best measures for research on blood-related changes in oxygen transport. With care, V(RBC,Evans) is suitable for clinical applications of blood-volume measurement.
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Affiliation(s)
- Christopher J Gore
- Department of Physiology, Australian Institute of Sport, P.O. Box 176, Belconnen, Australian Capital Territory, Australia.
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Bogaard HJ, Hopkins SR, Yamaya Y, Niizeki K, Ziegler MG, Wagner PD. Role of the autonomic nervous system in the reduced maximal cardiac output at altitude. J Appl Physiol (1985) 2002; 93:271-9. [PMID: 12070214 DOI: 10.1152/japplphysiol.00323.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After acclimatization to high altitude, maximal exercise cardiac output (QT) is reduced. Possible contributing factors include 1) blood volume depletion, 2) increased blood viscosity, 3) myocardial hypoxia, 4) altered autonomic nervous system (ANS) function affecting maximal heart rate (HR), and 5) reduced flow demand from reduced muscle work capability. We tested the role of the ANS reduction of HR in this phenomenon in five normal subjects by separately blocking the sympathetic and parasympathetic arms of the ANS during maximal exercise after 2-wk acclimatization at 3,800 m to alter maximal HR. We used intravenous doses of 8.0 mg of propranolol and 0.8 mg of glycopyrrolate, respectively. At altitude, peak HR was 170 +/- 6 beats/min, reduced from 186 +/- 3 beats/min (P = 0.012) at sea level. Propranolol further reduced peak HR to 139 +/- 2 beats/min (P = 0.001), whereas glycopyrrolate increased peak HR to sea level values, 184 +/- 3 beats/min, confirming adequate dosing with each drug. In contrast, peak O(2) consumption, work rate, and QT were similar at altitude under all drug treatments [peak QT = 16.2 +/- 1.2 (control), 15.5 +/- 1.3 (propranolol), and 16.2 +/- 1.1 l/min (glycopyrrolate)]. All QT results at altitude were lower than those at sea level (20.0 +/- 1.8 l/min in air). Therefore, this study suggests that, whereas the ANS may affect HR at altitude, peak QT is unaffected by ANS blockade. We conclude that the effect of altered ANS function on HR is not the cause of the reduced maximal QT at altitude.
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Affiliation(s)
- Harm J Bogaard
- Division of Physiology, Department of Medicine, University of California, San Diego, La Jolla 92093, USA
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23
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Abstract
Acute exposure to moderate altitude is likely to enhance cycling performance on flat terrain because the benefit of reduced aerodynamic drag outweighs the decrease in maximum aerobic power [maximal oxygen uptake (VO2max)]. In contrast, when the course is mountainous, cycling performance will be reduced at moderate altitude. Living and training at altitude, or living in an hypoxic environment (approximately 2500 m) but training near sea level, are popular practices among elite cyclists seeking enhanced performance at sea level. In an attempt to confirm or refute the efficacy of these practices, we reviewed studies conducted on highly-trained athletes and, where possible, on elite cyclists. To ensure relevance of the information to the conditions likely to be encountered by cyclists, we concentrated our literature survey on studies that have used 2- to 4-week exposures to moderate altitude (1500 to 3000 m). With acclimatisation there is strong evidence of decreased production or increased clearance of lactate in the muscle, moderate evidence of enhanced muscle buffering capacity (beta m) and tenuous evidence of improved mechanical efficiency (ME) of cycling. Our analysis of the relevant literature indicates that, in contrast to the existing paradigm, adaptation to natural or simulated moderate altitude does not stimulate red cell production sufficiently to increase red cell volume (RCV) and haemoglobin mass (Hb(mass)). Hypoxia does increase serum erthyropoietin levels but the next step in the erythropoietic cascade is not clearly established; there is only weak evidence of an increase in young red blood cells (reticulocytes). Moreover, the collective evidence from studies of highly-trained athletes indicates that adaptation to hypoxia is unlikely to enhance sea level VO2max. Such enhancement would be expected if RCV and Hb(mass) were elevated. The accumulated results of 5 different research groups that have used controlled study designs indicate that continuous living and training at moderate altitude does not improve sea level performance of high level athletes. However, recent studies from 3 independent laboratories have consistently shown small improvements after living in hypoxia and training near sea level. While other research groups have attributed the improved performance to increased RCV and VO2max, we cite evidence that changes at the muscle level (beta m and ME) could be the fundamental mechanism. While living at altitude but training near sea level may be optimal for enhancing the performance of competitive cyclists, much further research is required to confirm its benefit. If this benefit does exist, it probably varies between individuals and averages little more than 1%.
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Affiliation(s)
- A G Hahn
- Department of Physiology, Australian Institute of Sport, Canberra.
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Abstract
Since the first ascent of Mont Blanc by Jacques Balmat and Dr. Michel-Gabriel Paccard in 1786, numerous scientific events have taken place on the highest peak of Europe. Horace Benédict de Saussure, since his first ascent in 1787, made numerous observations on barometric pressure, temperature, geology, and mountain sickness on Mont Blanc. Over the next 100 years, scientists and physicians climbed Mont Blanc and made many interesting although anecdotal reports. Science on Mont Blanc exploded at the end of the 19th century. A major player at that time was Joseph Vallot (1854-1925), who constructed an observatory in 1890 at 4,358 m on the Rochers des Bosses and then moved it in 1898 to a better location at 4,350 m. There Vallot and invited scientists made observations over more than 30 years: studies in geology, glaciology, astronomy, cartography, meteorology, botany, physiology and medicine were performed and published in the seven volumes of the Annales de l'Observatoire du Mont Blanc, between 1893 and 1917, and in the Comptes Rendus de l'Académie des Sciences. While Jules Janssen and Xaver Imfeld were preparing the construction of the new observatory on the top of Mont Blanc, Dr. Jacottet died in 1891 at the Observatoire Vallot from a disease that was clearly attributed by Dr. Egli-Sinclair to the effect of high altitude. This was probably the first case of high altitude pulmonary edema documented by an autopsy and suspected to be directly due to high altitude. Extensive studies on ventilation were made from 1886 to 1900. Increase in ventilation with altitude was documented, with the phenomenon of "ventilatory acclimatization." Paul Bert's theories on the role of oxygen in acute mountain sickness were confirmed in 1903 and 1904 by studying the effects of oxygen inhalation. In 1913, Vallot documented for the first time the decrease in physical performance at the top of Mont Blanc using squirrels. After that pioneering era, few studies were done until 1984, when a team of the Association pour la Recherche en Physiologie de l'Environnement (ARPE) renovated the observatory and started to organize annual scientific expeditions.
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Affiliation(s)
- J P Richalet
- ARPE, Laboratoire Réponses Cellulaires et Fonctionnelles à l'Hypoxie, Université Paris 13, Bobigny, France.
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Imoberdorf R, Garlick PJ, McNurlan MA, Casella GA, Peheim E, Turgay M, Bärtsch P, Ballmer PE. Enhanced synthesis of albumin and fibrinogen at high altitude. J Appl Physiol (1985) 2001; 90:528-37. [PMID: 11160051 DOI: 10.1152/jappl.2001.90.2.528] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The acute effects of active and passive ascent to high altitude on plasma volume (PV) and rates of synthesis of albumin and fibrinogen have been examined. Measurements were made in two groups of healthy volunteers, initially at low altitude (550 m) and again on the day after ascent to high altitude (4,559 m). One group ascended by helicopter (air group, n = 8), whereas the other group climbed (foot group, n = 9), so that the separate contribution of physical exertion to the response could be delineated. PV was measured by dilution of (125)I-labeled albumin, whereas synthesis rates of albumin and fibrinogen were determined from the incorporation of isotope into protein after injection of [ring-(2)H(5)]phenylalanine. In the air group, there was no change in PV at high altitude, whereas, in the foot group, there was a 10% increase in PV (P < 0.01). Albumin synthesis (mg. kg(-1). day(-1)) increased by 13% in the air group (P = 0.058) and by 32% in the foot group (P < 0.001). Fibrinogen synthesis (mg. kg(-1). day(-1)) increased by 40% in the air group (P = 0.068) and by 100% in the foot group (P < 0.001). Hypoxia and alkalosis at high altitude did not differ between the groups. Plasma interleukin-6 was increased modestly in both groups but C-reactive protein was not changed in either group. It is concluded that increases in PV and plasma protein synthesis at high altitude result mainly from the physical exercise associated with climbing. However, a small stimulation of albumin and fibrinogen synthesis may be attributable to hypobaric hypoxia alone.
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Affiliation(s)
- R Imoberdorf
- Department of Internal Medicine, University of Berne, CH-3010 Berne, Switzerland.
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