{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T08:20:29Z","timestamp":1776327629928,"version":"3.50.1"},"reference-count":85,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,6,15]],"date-time":"2021-06-15T00:00:00Z","timestamp":1623715200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:p>Red blood cell 2,3-diphosphoglycerate (2,3-DPG) is one of the factors of rightward-shifted oxygen dissociation curves and decrease of Hb-O<jats:sub>2<\/jats:sub>affinity. The reduction of Hb-O<jats:sub>2<\/jats:sub>affinity is beneficial to O<jats:sub>2<\/jats:sub>unloading at the tissue level. In the current literature, there are no studies about the changes in 2,3-DPG level following acute exercise in moderate hypoxia in athletes. For this reason, the aim of this study was to analyze the effect of prolonged intense exercise under normoxic and hypoxic conditions on 2,3-DPG level in cyclists. Fourteen male trained cyclists performed a simulation of a 30 km time trial (TT) in normoxia and normobaric hypoxia (FiO<jats:sub>2<\/jats:sub>= 16.5%, ~2,000 m). During the TT, the following variables were measured: power, blood oxygen saturation (SpO<jats:sub>2<\/jats:sub>), and heart rate (HR). Before and immediately after exercise, the blood level of 2,3-DPG and acid\u2013base equilibrium were determined. The results showed that the mean SpO<jats:sub>2<\/jats:sub>during TT in hypoxia was 8% lower than in normoxia. The reduction of SpO<jats:sub>2<\/jats:sub>in hypoxia resulted in a decrease of average power by 9.6% (<jats:italic>p<\/jats:italic>&amp;lt; 0.001) and an increase in the 30 km TT completion time by 3.8% (<jats:italic>p<\/jats:italic>&amp;lt; 0.01) compared to normoxia. The exercise in hypoxia caused a significant (<jats:italic>p<\/jats:italic>&amp;lt; 0.001) decrease in 2,3-DPG level by 17.6%. After exercise in normoxia, a downward trend of 2,3-DPG level was also observed, but this effect was not statistically significant. The analysis also revealed that changes of acid\u2013base balance were significantly larger (<jats:italic>p<\/jats:italic>&amp;lt; 0.05) after exercise in hypoxia than in normoxia. In conclusion, intense exercise in hypoxic conditions leads to a decrease in 2,3-DPG concentration, primarily due to exercise-induced acidosis.<\/jats:p>","DOI":"10.3389\/fphys.2021.670977","type":"journal-article","created":{"date-parts":[[2021,6,15]],"date-time":"2021-06-15T07:48:47Z","timestamp":1623743327000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":25,"title":["Red Blood Cell 2,3-Diphosphoglycerate Decreases in Response to a 30 km Time Trial Under Hypoxia in Cyclists"],"prefix":"10.3389","volume":"12","author":[{"given":"Kamila","family":"P\u0142oszczyca","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mi\u0142osz","family":"Czuba","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ma\u0142gorzata","family":"Chalimoniuk","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robert","family":"Gajda","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marcin","family":"Baranowski","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2021,6,15]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"4","DOI":"10.1111\/j.1600-0609.1986.tb01764.x","article-title":"Red-cell metabolism in patients with iron deficiency","volume":"37","author":"Acharya","year":"1986","journal-title":"Scand. J. Haematol."},{"key":"ref2","doi-asserted-by":"publisher","first-page":"952","DOI":"10.1136\/jnnp.39.10.952","article-title":"2,3 diphosphoglycerate in Parkinson's disease","volume":"39","author":"Alevizos","year":"1976","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"937","DOI":"10.1113\/jphysiol.2006.113936","article-title":"Arterial oxygenation influences central motor output and exercise performance via effects on peripheral locomotor muscle fatigue in humans","volume":"575","author":"Amann","year":"2006","journal-title":"J. Physiol."},{"key":"ref4","doi-asserted-by":"publisher","first-page":"217","DOI":"10.2165\/00007256-199826040-00002","article-title":"Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine","volume":"26","author":"Atkinson","year":"1998","journal-title":"Sports Med."},{"key":"ref001","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1016\/j.cct.2003.10.016","article-title":"Assessment of blinding in clinical trials","volume":"25","author":"Bang","year":"2004","journal-title":"Control. Clin. Trials."},{"key":"ref5","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1542\/peds.64.4.483","article-title":"Red cell oxygen affinity hemoglobin type 2,3-difosfoglicerate and pH, a function of fetal development","volume":"64","author":"Bard","year":"1979","journal-title":"Pediatrics"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"1041","DOI":"10.1016\/0024-3205(69)90455-X","article-title":"Antagonistic influence of CO2 and 2,3 diphosphoglycerate on the Bohr effect of human haemoglobin","volume":"8","author":"Bauer","year":"1969","journal-title":"Life Sci."},{"key":"ref7","doi-asserted-by":"publisher","first-page":"700","DOI":"10.1172\/JCI106540","article-title":"Regulatory mechanisms of hemoglobin oxygen affinity in acidosis and alkalosis","volume":"50","author":"Bellingham","year":"1971","journal-title":"J. Clin. Invest."},{"key":"ref8","doi-asserted-by":"publisher","first-page":"162","DOI":"10.1016\/0006-291X(67)90228-8","article-title":"The effect of organic phosphates from the human erythrocyte on the allosteric properties of hemoglobin","volume":"26","author":"Benesch","year":"1967","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"e97932","DOI":"10.1371\/journal.pone.0097932","article-title":"Hemoglobin oxygen affinity in patients with cystic fibrosis","volume":"9","author":"B\u00f6ning","year":"2014","journal-title":"PLoS One"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1007\/BF00999936","article-title":"Changes in erythrocyte 2,3 diphosphoglycerate in women following short term maximal exercise","volume":"34","author":"Bonner","year":"1975","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref11","doi-asserted-by":"publisher","first-page":"193","DOI":"10.1007\/BF00421832","article-title":"2,3-diphosphoglycerate during exercise","volume":"43","author":"B\u00f6swart","year":"1980","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref12","doi-asserted-by":"publisher","first-page":"1524","DOI":"10.1152\/jappl.1982.52.6.1524","article-title":"Bohr effect and slope of the oxygen dissociation curve after physical training","volume":"52","author":"Braumann","year":"1982","journal-title":"J. Appl. Physiol. Respir. Environ. Exerc. Physiol."},{"key":"ref13","doi-asserted-by":"publisher","first-page":"29","DOI":"10.1146\/annurev.me.25.020174.000333","article-title":"2,3-DPG and erythrocyte oxygen affinity","volume":"25","author":"Brewer","year":"1974","journal-title":"Annu. Rev. Med."},{"key":"ref14","doi-asserted-by":"publisher","first-page":"1205","DOI":"10.1126\/science.171.3977.1205","article-title":"Erythrocyte metabolism: interaction with oxygen transport","volume":"171","author":"Brewer","year":"1971","journal-title":"Science"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"334","DOI":"10.1007\/BF00422849","article-title":"Red cell 2,3-DPG, ATP, and mean cell volume in highly trained athletes. Effect of long-term submaximal exercise","volume":"53","author":"Brodthagen","year":"1985","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref16","doi-asserted-by":"publisher","first-page":"479","DOI":"10.1080\/02640419308730016","article-title":"The effects of acute exercise on levels of erythrocyte 2,3-bisphosphoglycerate: a brief review","volume":"11","author":"Brown","year":"1993","journal-title":"J. Sports Sci."},{"key":"ref17","doi-asserted-by":"publisher","first-page":"425","DOI":"10.1007\/s40279-013-0042-0","article-title":"Sodium phosphate as an ergogenic aid","volume":"43","author":"Buck","year":"2013","journal-title":"Sports Med."},{"key":"ref18","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1249\/00005768-198406000-00011","article-title":"Effects of phosphate loading on 2,3-diphosphoglycerate and maximal oxygen uptake","volume":"16","author":"Cade","year":"1984","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref19","doi-asserted-by":"publisher","first-page":"i40","DOI":"10.1136\/bjsports-2013-092837","article-title":"The individual response to training and competition at altitude","volume":"47","author":"Chapman","year":"2013","journal-title":"Br. J. Sports Med."},{"key":"ref20","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1007\/s00421-007-0554-0","article-title":"The effect of acute simulated moderate altitude on power, performance and pacing strategies in well-trained cyclists","volume":"102","author":"Clark","year":"2007","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref21","doi-asserted-by":"publisher","first-page":"1287506","DOI":"10.1155\/2019\/1287506","article-title":"Intermittent hypoxic training at lactate threshold intensity improves aiming performance in well-trained biathletes with little change of cardiovascular variables","volume":"2019","author":"Czuba","year":"2019","journal-title":"Biomed. Res. Int."},{"key":"ref22","doi-asserted-by":"publisher","first-page":"149","DOI":"10.2478\/v10078-008-0012-z","article-title":"The influence of sodium phosphate supplementation on VO2max, serum 2,3-diphosphoglycerate level and heart rate in off-road cyclists","volume":"19","author":"Czuba","year":"2008","journal-title":"J. Hum. Kinet."},{"key":"ref23","first-page":"591","article-title":"Effects of sodium phosphate loading on aerobic power and capacity in off road cyclists","volume":"8","author":"Czuba","year":"2009","journal-title":"J. Sports Sci. Med."},{"key":"ref24","doi-asserted-by":"publisher","first-page":"1419","DOI":"10.1113\/JP279555","article-title":"With haemoglobin as with politics - should we shift right or left?","volume":"598","author":"Dempsey","year":"2020","journal-title":"J. Physiol."},{"key":"ref25","doi-asserted-by":"publisher","first-page":"1997","DOI":"10.1152\/jappl.1999.87.6.1997","article-title":"Exercise-induced arterial hypoxemia","volume":"87","author":"Dempsey","year":"1999","journal-title":"J. Appl. Physiol."},{"key":"ref26","doi-asserted-by":"publisher","first-page":"1475","DOI":"10.1113\/JP279161","article-title":"Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise","volume":"598","author":"Dominelli","year":"2020","journal-title":"J. Physiol."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"254","DOI":"10.1007\/BF00592506","article-title":"On the mechanisms of the hypoxia-induced increase of 2,3-diphosphoglycerate in erythrocytes","volume":"326","author":"Duhm","year":"1971","journal-title":"Pflugers Arch."},{"key":"ref28","doi-asserted-by":"publisher","first-page":"978","DOI":"10.1123\/ijspp.2013-0524","article-title":"Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers","volume":"9","author":"Faiss","year":"2014","journal-title":"Int. J. Sports Physiol. Perform."},{"key":"ref29","doi-asserted-by":"publisher","first-page":"191","DOI":"10.1046\/j.1423-0410.2000.7940191.x","article-title":"Red blood cell function and blood storage","volume":"79","author":"Hamasaki","year":"2000","journal-title":"Vox Sang."},{"key":"ref30","doi-asserted-by":"publisher","first-page":"105","DOI":"10.1055\/s-2008-1025650","article-title":"Red cell oxygen transport before and after short-term maximal swimming in dependence on training status","volume":"8","author":"Hasibeder","year":"1987","journal-title":"Int. J. Sports Med."},{"key":"ref31","doi-asserted-by":"publisher","first-page":"456","DOI":"10.1007\/BF00417993","article-title":"Effects of training on erythrocyte 2,3-diphosphoglycerate in normal men","volume":"57","author":"Hespel","year":"1988","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"E647","DOI":"10.1152\/ajpendo.1999.277.4.E647","article-title":"Effect of induced metabolic acidosis on human skeletal muscle metabolism during exercise","volume":"277","author":"Hollidge-Horvat","year":"1999","journal-title":"Am. J. Phys."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1007\/978-0-387-34817-9_3","article-title":"Exercise induced arterial hypoxemia: the role of ventilation-perfusion inequality and pulmonary diffusion limitation","volume":"588","author":"Hopkins","year":"2006","journal-title":"Adv. Exp. Med. Biol."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1249\/MSS.0b013e31818cb278","article-title":"Progressive statistics for studies in sports medicine and exercise science","volume":"41","author":"Hopkins","year":"2009","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref35","first-page":"5","article-title":"Relationships between blood oxygen parameters in patients with chronic obstructive lung disease","volume":"35","author":"Illuchev","year":"1993","journal-title":"Folia. Med."},{"key":"ref36","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1007\/BF01015222","article-title":"Effect of high intensity interval training on 2,3-diphosphoglycerate at rest and after maximal exercise","volume":"52","author":"Katz","year":"1984","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref37","doi-asserted-by":"publisher","first-page":"800","DOI":"10.1097\/00005768-200004000-00012","article-title":"EPO, red cells, and serum transferrin receptor in continuous and intermittent hypoxia","volume":"32","author":"Koistinen","year":"2000","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref38","first-page":"292","article-title":"The effect of physical exercise on 2,3-diphosphoglyceride (2,3-DPG) concentration in erythrocytes","volume":"27","author":"Ku\u0144ski","year":"1976","journal-title":"Acta Physiol. Pol."},{"key":"ref39","doi-asserted-by":"publisher","first-page":"481","DOI":"10.1055\/s-2003-42012","article-title":"Reproducibility of a laboratory-based 40-km cycle time-trial on a stationary wind-trainer in highly trained cyclists","volume":"24","author":"Laursen","year":"2003","journal-title":"Int. J. Sports Med."},{"key":"ref40","doi-asserted-by":"publisher","first-page":"1486","DOI":"10.1152\/jappl.1988.64.4.1486","article-title":"Linear relationship between VO2max and VO2max decrement during exposure to acute hypoxia","volume":"64","author":"Lawler","year":"1988","journal-title":"J. Appl. Physiol."},{"key":"ref41","doi-asserted-by":"publisher","first-page":"2652","DOI":"10.1172\/JCI105948","article-title":"Effect of altitude on oxygen binding by hemoglobin and on organic phosphate levels","volume":"47","author":"Lenfant","year":"1968","journal-title":"J. Clin. Invest."},{"key":"ref42","doi-asserted-by":"publisher","first-page":"113","DOI":"10.1016\/j.transci.2004.12.002","article-title":"The effect of pre-storage cooling on 2,3-DPG levels in red cells stored in SAG-M","volume":"33","author":"Llohn","year":"2005","journal-title":"Transfus. Apher. Sci."},{"key":"ref43","doi-asserted-by":"publisher","first-page":"2251","DOI":"10.1007\/s00421-017-3712-z","article-title":"Changes in acid\u2013base and ion balance during exercise in normoxia and normobaric hypoxia","volume":"117","author":"L\u00fchker","year":"2017","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"544","DOI":"10.1111\/j.1365-2044.1977.tb10002.x","article-title":"Red cell 2,3-diphosphoglycerate and oxygen affinity","volume":"32","author":"MacDonald","year":"1977","journal-title":"Anaesthesia"},{"key":"ref45","doi-asserted-by":"publisher","first-page":"51","DOI":"10.1055\/s-2007-1021020","article-title":"Red blood cell function in hypoxia at altitude and exercise","volume":"15","author":"Mairb\u00e4url","year":"1994","journal-title":"Int. J. Sports Med."},{"key":"ref46","doi-asserted-by":"publisher","first-page":"332","DOI":"10.3389\/fphys.2013.00332","article-title":"Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells","volume":"4","author":"Mairb\u00e4url","year":"2013","journal-title":"Front. Physiol."},{"key":"ref47","doi-asserted-by":"publisher","first-page":"1403","DOI":"10.1152\/jappl.1983.55.5.1403","article-title":"Training-dependent changes of red cell density and erythrocytic oxygen transport","volume":"55","author":"Mairb\u00e4url","year":"1983","journal-title":"J. Appl. Physiol. Respir. Environ. Exerc. Physiol."},{"key":"ref48","doi-asserted-by":"publisher","first-page":"174","DOI":"10.1007\/BF00715001","article-title":"Regulation of red cell 2,3-DPG and Hb-O2-affinity during acute exercise","volume":"55","author":"Mairb\u00e4url","year":"","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref49","doi-asserted-by":"publisher","first-page":"594","DOI":"10.1007\/BF00584026","article-title":"Beneficial effects of exercising at moderate altitude on red cell oxygen transport and on exercise performance","volume":"406","author":"Mairb\u00e4url","year":"","journal-title":"Pflugers Arch."},{"key":"ref50","doi-asserted-by":"publisher","first-page":"177","DOI":"10.1007\/BF00428869","article-title":"Changes in 2,3-Diphosphoglycerate (2,3-DPG) after exercise","volume":"46","author":"Meen","year":"1981","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref51","doi-asserted-by":"publisher","first-page":"663","DOI":"10.1007\/s00421-007-0457-0","article-title":"Determinants of maximal oxygen uptake in moderate acute hypoxia in endurance athletes","volume":"100","author":"Mollard","year":"2007","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref52","doi-asserted-by":"publisher","first-page":"489","DOI":"10.2165\/00007256-200131070-00004","article-title":"Tests of cycling performance","volume":"31","author":"Paton","year":"2001","journal-title":"Sports Med."},{"key":"ref53","doi-asserted-by":"publisher","first-page":"e0224207","DOI":"10.1371\/journal.pone.0224207","article-title":"Acute normobaric hypoxia does not affect the simultaneous exercise-induced increase in circulating BDNF and GDNF in young healthy men: a feasibility study","volume":"14","author":"Piotrowicz","year":"2019","journal-title":"PLoS One"},{"key":"ref54","doi-asserted-by":"publisher","first-page":"5569","DOI":"10.3390\/ijms21155569","article-title":"Exercise-induced elevated BDNF level does not prevent cognitive impairment due to acute exposure to moderate hypoxia in well-trained athletes","volume":"21","author":"Piotrowicz","year":"2020","journal-title":"Int. J. Mol. Sci."},{"key":"ref55","doi-asserted-by":"publisher","first-page":"375","DOI":"10.3389\/fphys.2018.00375","article-title":"The effects of altitude training on erythropoietic response and hematological variables in adult athletes: a narrative review","volume":"9","author":"P\u0142oszczyca","year":"2018","journal-title":"Front. Physiol."},{"key":"ref56","doi-asserted-by":"publisher","first-page":"344","DOI":"10.1113\/jphysiol.1964.sp007335","article-title":"Blood volume and haemoglobin concentration at altitudes above 18,000 ft. (5500 m)","volume":"170","author":"Pugh","year":"1964","journal-title":"J. Physiol."},{"key":"ref57","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1007\/BF00421514","article-title":"Response of erythrocytic 2,3-diphosphoglycerate to strenuous exercise","volume":"40","author":"Ramsey","year":"1979","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref58","doi-asserted-by":"publisher","first-page":"421","DOI":"10.1111\/j.1432-1033.1977.tb11333.x","article-title":"PH-dependent changes of 2,3-bisphosphoglycerate in human red cells during transitional and steady states in vitro","volume":"73","author":"Rapoport","year":"1977","journal-title":"Eur. J. Biochem."},{"key":"ref59","doi-asserted-by":"publisher","first-page":"199","DOI":"10.1007\/BF00431026","article-title":"Effect of long-term training and acute physical exercise on red cell 2,3-diphosphoglycerate","volume":"42","author":"Remes","year":"1979","journal-title":"Eur. J. Appl. Physiol. Occup. Physiol."},{"key":"ref60","doi-asserted-by":"publisher","first-page":"95","DOI":"10.1159\/000205611","article-title":"Effects of exercise on haematologic parameters, serum iron, serum ferritin, red cell 2,3-diphosphoglycerate and creatine contents, and serum erythropoietin in long-distance runners during basal training","volume":"80","author":"Ricci","year":"1988","journal-title":"Acta Haematol."},{"key":"ref62","doi-asserted-by":"publisher","first-page":"329","DOI":"10.3109\/00365517209080248","article-title":"Effect of exposure to simulated high altitude on human red cell phosphates and oxygen affinity of hemoglobin, influence of exercise","volume":"29","author":"R\u00f6rth","year":"1972","journal-title":"Scand. J. Clin. Lab. Invest."},{"key":"ref63","first-page":"1105","article-title":"Enzymes controlling 2,3-diphosphoglycerate in human erythrocytes","volume":"29","author":"Rose","year":"1970","journal-title":"Fed. Proc."},{"key":"ref64","doi-asserted-by":"publisher","first-page":"928","DOI":"10.1080\/02640410400005933","article-title":"Altitude and endurance training","volume":"22","author":"Rusko","year":"2004","journal-title":"J. Sports Sci."},{"key":"ref65","doi-asserted-by":"publisher","first-page":"191","DOI":"10.1016\/0034-5687(86)90041-1","article-title":"The role of 2,3-DPG in the oxygen transport at altitude","volume":"64","author":"Samaja","year":"1986","journal-title":"Respir. Physiol."},{"key":"ref66","doi-asserted-by":"publisher","first-page":"680","DOI":"10.1249\/MSS.0000000000000810","article-title":"Cycling time trial is more altered in hypobaric than normobaric hypoxia","volume":"48","author":"Saugy","year":"2016","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref67","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1007\/s00421-004-1159-5","article-title":"Control of erythropoiesis after high altitude acclimatization","volume":"93","author":"Savourey","year":"2004","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref68","doi-asserted-by":"publisher","first-page":"490","DOI":"10.1007\/BF00417998","article-title":"Training induced effects on blood volume, erythrocyte turnover and haemoglobin oxygen binding properties","volume":"57","author":"Schmidt","year":"1988","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref69","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1111\/j.1600-0838.2008.00833.x","article-title":"Effects of various training modalities on blood volume","volume":"18","author":"Schmidt","year":"2008","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"ref70","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1055\/s-2001-13813","article-title":"Reliability of mean power recorded during indoor and outdoor self-paced 40 km cycling time-trials","volume":"22","author":"Smith","year":"2001","journal-title":"Int. J. Sports Med."},{"key":"ref71","first-page":"17","article-title":"The 2,3-DPG levels of human red blood cells during an incremental exercise test: relationship to the blood acid-base balance","volume":"47","author":"Spodaryk","year":"1998","journal-title":"Physiol. Res."},{"key":"ref72","doi-asserted-by":"publisher","first-page":"940","DOI":"10.1055\/s-2007-964977","article-title":"Reproducibility of a laboratory based 20-km time trial evaluation in competitive cyclists using the Velotron Pro ergometer","volume":"28","author":"Sporer","year":"2007","journal-title":"Int. J. Sports Med."},{"key":"ref73","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1016\/0003-9861(72)90138-5","article-title":"The effect of normal red cell constituents on the activities of red cell enzymes","volume":"148","author":"Srivastava","year":"1972","journal-title":"Arch. Biochem. Biophys."},{"key":"ref74","doi-asserted-by":"publisher","first-page":"1309","DOI":"10.1152\/jappl.1988.64.4.1309","article-title":"Operation Everest II: oxygen transport during exercise at extreme simulated altitude","volume":"64","author":"Sutton","year":"1988","journal-title":"J. Appl. Physiol."},{"key":"ref75","first-page":"238","article-title":"Alterations in 2,3-DPG and P50 with maximal and submaximal exercise","volume":"6","author":"Taunton","year":"1974","journal-title":"Med. Sci. Sports"},{"key":"ref76","doi-asserted-by":"publisher","first-page":"658","DOI":"10.1152\/jappl.1974.37.5.658","article-title":"Oxygen transport and oxyhemoglobin dissociation during prolonged muscular work","volume":"37","author":"Thomson","year":"1974","journal-title":"J. Appl. Physiol."},{"key":"ref77","author":"Urbaniak","year":"2013"},{"key":"ref78","doi-asserted-by":"publisher","first-page":"21","DOI":"10.1146\/annurev.ph.58.030196.000321","article-title":"Determinants of maximal oxygen transport and utilization","volume":"58","author":"Wagner","year":"1996","journal-title":"Annu. Rev. Physiol."},{"key":"ref79","doi-asserted-by":"publisher","first-page":"6","DOI":"10.1111\/j.1400-1843.2007.01068.x","article-title":"Pulmonary gas exchange","volume":"12","author":"Wagner","year":"2007","journal-title":"Respirology"},{"key":"ref80","doi-asserted-by":"publisher","first-page":"1653","DOI":"10.1007\/s00421-015-3145-5","article-title":"Endurance exercise performance in acute hypoxia is influenced by expiratory flow limitation","volume":"115","author":"Weavil","year":"2015","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref81","doi-asserted-by":"publisher","first-page":"404","DOI":"10.1007\/s00421-005-0081-9","article-title":"Linear decrease in VO2max and performance with increasing altitude in endurance athletes","volume":"96","author":"Wehrlin","year":"2006","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref82","doi-asserted-by":"publisher","first-page":"1938","DOI":"10.1152\/japplphysiol.01284.2005","article-title":"Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes","volume":"100","author":"Wehrlin","year":"2006","journal-title":"J. Appl. Physiol."},{"key":"ref83","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/0034-5687(80)90100-0","article-title":"Predicted gas exchange on the summit of Mt. Everest","volume":"42","author":"West","year":"1980","journal-title":"Respir. Physiol."},{"key":"ref84","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1016\/j.resp.2007.03.011","article-title":"The role of hemoglobin oxygen affinity in oxygen transport at high altitude","volume":"158","author":"Winslow","year":"2007","journal-title":"Respir. Physiol. 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