Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?Commentaries on Viewpoint: Time for a new metric for hypoxic dose?
2016; American Physiological Society; Volume: 121; Issue: 1 Linguagem: Inglês
10.1152/japplphysiol.00460.2016
ISSN8750-7587
AutoresGrégoire P. Millet, Jon Peter Wehrlin, Juha E. Peltonen, Keren Constantini, Vasanth Kumar, Walter Schmidt, Franck Brocherie, Olivier Girard, Severin Troesch, Anna Hauser, Thomas Steiner, Heikki Rusko, Timothy J. Fulton, Daniel G. Hursh, Tyler J. Noble, Hunter L. Paris, Chad C. Wiggins, Robert F. Chapman, Benjamin D. Levine,
Tópico(s)Chronic Obstructive Pulmonary Disease (COPD) Research
ResumoPerspectivesCommentaries on Viewpoint: Time for a new metric for hypoxic dose?Published Online:22 Jul 2016MoreSectionsPDF (45 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Grégoire P. Millet.Franck Brocherie.Olivier Girard.NEW METRIC FOR THE HYPOXIC STIMULUS, NOT FOR THE RESPONSEto the editor: The proposal by our well-respected colleagues (2) to introduce a new metric—incorporating the altitude elevation and the total exposure duration, termed “kilometer hours”—for better describing the “hypoxic dose” is decidedly a step forward. By only quantifying the “external” stress, this metric presents several limitations: It suggests a linear relationship between altitude elevation and saturation decrease [but the Fick curve is curvilinear (3)] or that it applies to all athletes irrespectively of their training background [but elite endurance athletes suffer the largest decrease in V̇o2 max (1)], altitude experience [but elite athletes who have had previous hypoxic exposure better adapt to hypoxic condition (4)], or type of hypoxia [but hypobaric vs. normobaric hypoxia induces larger desaturation (5)].The large intersubject variability in the physiological responses to a given “hypoxic dose” implies that the magnitude of the stimulus rather than the altitude elevation should instead be considered. We therefore propose a new metric based on the sustained duration at a given arterial saturation level. Hence, desaturation levels in normoxia (exercise-induced arterial hypoxemia) or in hypoxia (3) predict the decrement in V̇o2 max in hypoxia and therefore the amplitude of the “hypoxic stimulus.” This metric termed “saturation hours” is defined as %·h = (98/s - 1) × h × 100, where s is the saturation value (in %) and h the time (in hours) sustained at any second level.Practically, with the development of new sport gears incorporating the oximeter inside the textile, this metric will readily be measured without any disturbances to individuals.REFERENCES1. Faiss R, von Orelli C, Dériaz O, Millet GP. Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers. Int J Sports Physiol Perform 9: 978–984, 2014.Crossref | ISI | Google Scholar2. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar3. Mollard P, Woorons X, Letournel M, Lamberto C, Favret F, Pichon A, Beaudry M, Richalet JP. Determinants of maximal oxygen uptake in moderate acute hypoxia in endurance athletes. Eur J Appl Physiol 100: 663–6732007.Crossref | PubMed | ISI | Google Scholar4. Pugliese L, Serpiello FR, Millet GP, La Torre A. Training diaries during altitude training camp in two olympic champions: an observational case study. J Sports Sci Med 13: 666–6722014.ISI | Google Scholar5. Saugy JJ, Schmitt L, Cejuela R, Faiss R, Hauser A, Wehrlin JP, Rudaz B, Delessert A, Robinson N, Millet GP. Comparison of “Live High-Train Low” in normobaric versus hypobaric hypoxia. PLoS One 9: e1144182014.Crossref | ISI | Google ScholarREFERENCES1. Faiss R, von Orelli C, Dériaz O, Millet GP. Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers. Int J Sports Physiol Perform 9: 978–984, 2014.Crossref | ISI | Google Scholar2. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar3. Mollard P, Woorons X, Letournel M, Lamberto C, Favret F, Pichon A, Beaudry M, Richalet JP. Determinants of maximal oxygen uptake in moderate acute hypoxia in endurance athletes. Eur J Appl Physiol 100: 663–6732007.Crossref | PubMed | ISI | Google Scholar4. Pugliese L, Serpiello FR, Millet GP, La Torre A. Training diaries during altitude training camp in two olympic champions: an observational case study. J Sports Sci Med 13: 666–6722014.ISI | Google Scholar5. Saugy JJ, Schmitt L, Cejuela R, Faiss R, Hauser A, Wehrlin JP, Rudaz B, Delessert A, Robinson N, Millet GP. Comparison of “Live High-Train Low” in normobaric versus hypobaric hypoxia. PLoS One 9: e1144182014.Crossref | ISI | Google ScholarJon Peter Wehrlin, Severin Troesch, Anna Hauser, and Thomas Steiner.COMMENTARY ON VIEWPOINT: TIME FOR A NEW METRIC HYPOXIC DOSE?to the editor: It is a very good idea of Garvican-Lewis, Sharpe, and Gore (2) to initiate this discussion with a new metric hypoxic dose by combining living altitude in kilometers with hours spent at altitude (“kilometer hours”; km/h) in the field of altitude training science. However, is the altitude component of the dose really linear? Would exposure at lower altitudes overestimate the hypoxic dose because some sort of “altitude-threshold” exists? Physiological mechanisms behind a possible “altitude-threshold” could be associated with the s-shape of the oxyhemoglobin saturation curve: at altitudes above ∼2,000 m the desaturation of athletes would occur on the steeper part of the curve resulting in more substantial increases in sEpo (∼90% at 2,400 m compared with ∼30% at 1,800 m after 24 h) (1). As the authors indicated, most recommendations for natural living altitudes are between 2,000 and 2,500 m (2, 5). Our Swiss experiences are that only ∼1/6 of the endurance athletes living at 1,800 m (4) and 2/3 living at 2,200 m (3) have a substantially increased hemoglobin mass after a 3-week altitude training camp. Could the proposed method be “optimized,” if “kilometer” is weighted in a way, that there is a larger dose-difference for altitudes below and above an “altitude-threshold”? For example, start counting kilometers above 1,300 m, with double hours at 1,800 m needed to reach the same “dose” as compared with 2,300 m. Additionally, for elite sport settings, one should also keep in mind that the hemoglobin-mass-response to a given “dose” has been shown to be largely idiosyncratic, thereby requiring individualized recommendations (3, 4).REFERENCES1. 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) 116: 595–603, 2014.Link | ISI | Google Scholar2. Garvican LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar3. Hauser A, Schmitt L, Troesch S, Saugy JJ, Cejuela-Anta R, Faiss R, Robinson N, Wehrlin JP, Millet GP. Similar hemoglobin mass response in hypobaric and normobaric hypoxia in athletes. Med Sci Sports Exerc 48: 734–741, 2016.Crossref | ISI | Google Scholar4. Troesch S, Hauser A, Steiner T, Gruenenfelder A, Heyer L, Gojanovic B, Wehrlin JP. Individual hemoglobin mass response to altitude training at 1800m in elite endurance athletes. In: Abstract book: 20th Annual Congress of the European College of Sport Science, edited by Radmann A, Hedenborg S, and Tsolakidis E. Malmö: 2015.Google Scholar5. Wilber RL, Stray-Gundersen J, Levine BD. Effect of hypoxic “dose” on physiological responses and sea-level performance. Med Sci Sports Exerc 39: 1590–1599, 2007.Crossref | ISI | Google ScholarREFERENCES1. 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) 116: 595–603, 2014.Link | ISI | Google Scholar2. Garvican LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar3. Hauser A, Schmitt L, Troesch S, Saugy JJ, Cejuela-Anta R, Faiss R, Robinson N, Wehrlin JP, Millet GP. Similar hemoglobin mass response in hypobaric and normobaric hypoxia in athletes. Med Sci Sports Exerc 48: 734–741, 2016.Crossref | ISI | Google Scholar4. Troesch S, Hauser A, Steiner T, Gruenenfelder A, Heyer L, Gojanovic B, Wehrlin JP. Individual hemoglobin mass response to altitude training at 1800m in elite endurance athletes. In: Abstract book: 20th Annual Congress of the European College of Sport Science, edited by Radmann A, Hedenborg S, and Tsolakidis E. Malmö: 2015.Google Scholar5. Wilber RL, Stray-Gundersen J, Levine BD. Effect of hypoxic “dose” on physiological responses and sea-level performance. Med Sci Sports Exerc 39: 1590–1599, 2007.Crossref | ISI | Google ScholarJuha E. Peltonen.Author AffiliationsUniversity of Helsinki.Heikki K. Rusko.COMMENTARY ON VIEWPOINT: TIME FOR A NEW METRIC FOR HYPOXIC DOSE?to the editor: Garvican-Lewis et al. (3) are to be congratulated for their “kilometer hours” (km/h) approach predicting increasing response along with increasing hypoxic dose during altitude training. Previous literature has clearly shown that both endurance training and hypoxic exposure as such can increase hemoglobin mass (Hbmass), and the responses to their doses are individual. Wehrlin et al. (5) with a 1,080 km/h (24 days 18 h/day, 2,500 m) showed an average 5.3% increase in Hbmass with all athletes showing a positive response. Siebenmann et al. (4) reported no change in average Hbmass after 1,328 km/h (4 wk, 16 h/day, 3,000 m). This greater dose was beneficial for some athletes, but trivial or detrimental for others, leading to no change on average. With an average 6% increase in red cell mass volume, Chapman et al. (1) did not show any dose response effect after 4 wk “living high, training high and low” between 1,780, 2,085, 2,454, and 2,800 m. Their study suggests that increasing the dose by increasing the altitude above optimum may not provide any benefit (1). After more extreme hypoxic dose, a 72-day self-supported Mt. Everest expedition (>9,000 km/h), Cheung et al. (2) reported a wide scale of positive, negative, and no change responses in Hbmass. Thus the suggested model and the present literature, analogously with our own unpublished data using the km/h approach, rather highlight the need for careful evaluation of all factors influencing athletes' adaptation than solves the problem of how to determine hypoxic dose in elite sports.REFERENCES1. 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) 116: 595–603, 2014.Link | ISI | Google Scholar2. Cheung SS, Mutanen NE, Karinen HM, Koponen AS, Kyröläinen H, Tikkanen HO, Peltonen JE. Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day mt. Everest expedition. High Alt Med Biol 15: 331–340, 2014.Crossref | ISI | Google Scholar3. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar4. Siebenmann C, Robach P, Jacobs RA, Rasmussen P, Nordsborg N, Diaz V, Christ A, Olsen NV, Maggiorini M, Lundby C. “Live high-train low” using normobaric hypoxia: a double-blinded, placebo-controlled study. J Appl Physiol (1985) 112: 106–117, 2012.Link | ISI | Google Scholar5. Wehrlin JP, Zuest P, Hallén J, Marti B. Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes. J Appl Physiol (1985) 100: 1938–1945, 2006.Link | ISI | Google ScholarREFERENCES1. 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) 116: 595–603, 2014.Link | ISI | Google Scholar2. Cheung SS, Mutanen NE, Karinen HM, Koponen AS, Kyröläinen H, Tikkanen HO, Peltonen JE. Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day mt. Everest expedition. High Alt Med Biol 15: 331–340, 2014.Crossref | ISI | Google Scholar3. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar4. Siebenmann C, Robach P, Jacobs RA, Rasmussen P, Nordsborg N, Diaz V, Christ A, Olsen NV, Maggiorini M, Lundby C. “Live high-train low” using normobaric hypoxia: a double-blinded, placebo-controlled study. J Appl Physiol (1985) 112: 106–117, 2012.Link | ISI | Google Scholar5. Wehrlin JP, Zuest P, Hallén J, Marti B. Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes. J Appl Physiol (1985) 100: 1938–1945, 2006.Link | ISI | Google ScholarKeren Constantini, Timothy J. Fulton, Daniel G. Hursh, Tyler J. Noble, Hunter L. R. Paris, Chad C. Wiggins, and Robert F. Chapman.Author AffiliationsIndiana University.Benjamin D. Levine.COMMENTARY ON VIEWPOINT: TIME FOR A NEW METRIC FOR HYPOXIC DOSE?to the editor: Although exposure to some effective dose of hypobaric hypoxia provides a clear stimulus to increase hemoglobin (Hb) mass (3), numerous physiological responses to normobaric hypoxia have well documented differences to hypobaric hypoxia (4). Because of these discrepancies, we believe the conditions should not be treated as equal, and other meta-analyses (e.g., Ref. 1) have differentiated between “natural” and “artificial” hypoxic exposures. Additionally, given that all but one of the included studies consisted of highly trained subjects, the authors may wish to exclude the Siebenmann et al. study (5), which described subjects as “sedentary to moderately trained individuals who were not involved in high-level sport.” Finally, the model would benefit from a clear establishment of a minimum threshold, both from an altitude and a duration perspective, as the authors note both short duration high/extreme altitude exposure and chronic residence at mild altitude are each ineffective at increasing Hb mass.We would be excited to see an expanded model that accounts for the above concerns, thus addressing the sensitivity in what is already a thin air of certainty in regards to hypoxic training.REFERENCES1. Bonetti DL, Hopkins WG. Sea-level exercise performance following adaptation to hypoxia: a meta-analysis. Sports Med 39: 107–127, 2009.Crossref | PubMed | ISI | Google Scholar2. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar3. Levine BD, Stray-Gundersen J. Dose-response of altitude training: how much altitude is enough? in Hypoxia and Exercise. Springer, 2006, p. 233–247.Google Scholar4. Millet GP, Faiss R, Pialoux V. Point:Counterpoint: Hypobaric hypoxia induces/does not induce different responses from normobaric hypoxia. J Appl Physiol 112: 1783–1784, 2012.Link | ISI | Google Scholar5. Siebenmann C, Cathomen A, Hug M, Keiser S, Lundby AKM, Hilty MP, Goetze JP, Rasmussen P, Lundby C. Hemoglobin mass and intravascular volume kinetics during and after exposure to 3,454 m altitude. J Appl Physiol 119: 1194–1201, 2015.Link | ISI | Google ScholarREFERENCES1. Bonetti DL, Hopkins WG. Sea-level exercise performance following adaptation to hypoxia: a meta-analysis. Sports Med 39: 107–127, 2009.Crossref | PubMed | ISI | Google Scholar2. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar3. Levine BD, Stray-Gundersen J. Dose-response of altitude training: how much altitude is enough? in Hypoxia and Exercise. Springer, 2006, p. 233–247.Google Scholar4. Millet GP, Faiss R, Pialoux V. Point:Counterpoint: Hypobaric hypoxia induces/does not induce different responses from normobaric hypoxia. J Appl Physiol 112: 1783–1784, 2012.Link | ISI | Google Scholar5. Siebenmann C, Cathomen A, Hug M, Keiser S, Lundby AKM, Hilty MP, Goetze JP, Rasmussen P, Lundby C. Hemoglobin mass and intravascular volume kinetics during and after exposure to 3,454 m altitude. J Appl Physiol 119: 1194–1201, 2015.Link | ISI | Google ScholarVasantha H. S. Kumar.COMMENTARY ON VIEWPOINT: TIME FOR A NEW HYPOXIC DOSE?to the editor: Guidelines for simulated altitude exposure suggest athletes should spend around 14 h per day at 3,000 m for 3 weeks (300 h of exposure) to observe a mean increase in hemoglobin mass of 3–5% (3). Similarly, hypoxic exposure for 3–4 weeks at >2,200 m altitude will elicit a 3–5% increase in hemoglobin mass (2), with 4 weeks exposure believed to accelerate erythropoiesis (4). Hypoxia in both these occasions is influenced by altitude and the duration of hypoxia. The new metric of hypoxic dosing (1) addresses this problem, ensuring standardization of the hypoxic dose at various altitudes and hence will allow for comparing physiologic and nonphysiologic effects on body systems. The hypoxic dose as per the new metric for the studies mentioned above will be 882-1,478 km/h (2, 3). There have been questions regarding the minimum altitude and the extent of duration that results in “hypoxic dose” for physiologic changes to occur. The new metric is a good starting point that combines altitude and duration to measure outcomes across studies. The hypoxic dose per the new metric is predominantly in the range of 600-1,500 km/h that results in 3–6% change in hemoglobin mass across multiple studies (1). As the relationship between altitude and hypoxia is not exactly linear and various factors could influence physiologic adaptation or training performance, knowing the baseline (“hypoxic dose”) will make interpretation more well defined. The new metric may help to further characterize the minimum “dose” required for optimal performance, percent change in hemoglobin mass and other measures of physiologic adaptation.REFERENCES1. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar2. Rusko HK, Tikkanen HO, Peltonen JE. Altitude and endurance training. J Sports Sci 22: 928–944, 2004.Crossref | ISI | Google Scholar3. Saunders PU, Garvican-Lewis LA, Schmidt WF, Gore CJ. Relationship between changes in haemoglobin mass and maximal oxygen uptake after hypoxic exposure. Br J Sports Med 47, Suppl 1: i26–i30, 2013.Crossref | ISI | Google Scholar4. Wilber RL, Stray-Gundersen J, Levine BD. Effect of hypoxic “dose” on physiological responses and sea-level performance. Med Sci Sports Exerc 39: 1590–1599, 2007.Crossref | ISI | Google ScholarREFERENCES1. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Link | ISI | Google Scholar2. Rusko HK, Tikkanen HO, Peltonen JE. Altitude and endurance training. J Sports Sci 22: 928–944, 2004.Crossref | ISI | Google Scholar3. Saunders PU, Garvican-Lewis LA, Schmidt WF, Gore CJ. Relationship between changes in haemoglobin mass and maximal oxygen uptake after hypoxic exposure. Br J Sports Med 47, Suppl 1: i26–i30, 2013.Crossref | ISI | Google Scholar4. Wilber RL, Stray-Gundersen J, Levine BD. Effect of hypoxic “dose” on physiological responses and sea-level performance. Med Sci Sports Exerc 39: 1590–1599, 2007.Crossref | ISI | Google ScholarWalter F. J. Schmidt.Author AffiliationsUniversity of Bayreuth, Germany.COMMENTARY ON VIEWPOINT: TIME FOR A NEW METRIC FOR HYPOXIC DOSE?to the editor: The actual model which includes the degree of altitude as an equivalent parameter as the exposure time to hypoxia (1) is a systematic further development of the former model using just the exposure time (2), which was only valid for athletes training at a relatively narrow range of altitude.The authors correctly mention possible limitations concerning the minimum hypoxic dose for altitude and hypoxic exposure time. It seems to be also interesting if the new model is applicable to athletes living permanently in hypoxia. Whenever it is almost not possible to compare identical athletes under normoxic and chronic hypoxic conditions cross-sectional studies on elite cyclists show bigger increases under chronic altitude conditions (2,600 m) than calculated by the model [11 vs. 7.7% (4)]. For these cases a modification of the model should be considered.Following the idea of the authors that athletes who want to increase their Hb-mass by altitude training may choose between a relatively long stay at lower or a shorter stay at higher altitude for a fixed increase in Hb-mass they have to consider if the hemoglobin gained at altitude can be transferred to low altitude, where the competition takes place. As demonstrated by Ryan et al. (3) a strong increase in Hb-mass after 16 days at high altitude (5,260 m) is almost completely abolished after some days at lower altitude. As the return from moderate altitude is not associated with remarkable red cell destruction, for practical reasons an altitude threshold for red cell cytolysis has to be determined.REFERENCES1. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar2. Gore CJ, Sharpe K, Garvican-Lewis LA, Saunders PU, Humberstone CE, Robertson EY, Wachsmuth NB, Clark SA, McLean BD, Friedmann-Bette B, Neya M, Pottgiesser T, Schumacher YO, Schmidt WF. Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis. Br J Sports Med 47, Suppl 1: i31–i39, 2013.Crossref | ISI | Google Scholar3. 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 9: e108788, 2014.Crossref | PubMed | ISI | Google Scholar4. Schmidt W, Heinicke K, Rojas J, Manuel Gomez J, Serrato M, Mora M, Wolfarth B, Schmid A, Keul J. Blood volume and hemoglobin mass in endurance athletes from moderate altitude. Med Sci Sports Exerc 34: 1934–1940, 2002.Crossref | ISI | Google ScholarREFERENCES1. Garvican-Lewis LA, Sharpe K, Gore CJ. Viewpoint: Time for a new metric for hypoxic dose? J Appl Physiol; 10.1152/japplphysiol.00579.2015.Google Scholar2. Gore CJ, Sharpe K, Garvican-Lewis LA, Saunders PU, Humberstone CE, Robertson EY, Wachsmuth NB, Clark SA, McLean BD, Friedmann-Bette B, Neya M, Pottgiesser T, Schumacher YO, Schmidt WF. Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis. Br J Sports Med 47, Suppl 1: i31–i39, 2013.Crossref | ISI | Google Scholar3. 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 9: e108788, 2014.Crossref | PubMed | ISI | Google Scholar4. Schmidt W, Heinicke K, Rojas J, Manuel Gomez J, Serrato M, Mora M, Wolfarth B, Schmid A, Keul J. Blood volume and hemoglobin mass in endurance athletes from moderate altitude. Med Sci Sports Exerc 34: 1934–1940, 2002.Crossref | ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByLimitation of Maximal Heart Rate in Hypoxia: Mechanisms and Clinical Importance23 July 2018 | Frontiers in Physiology, Vol. 9Hypobaric live high-train low does not improve aerobic performance more than live low-train low in cross-country skiers22 March 2018 | Scandinavian Journal of Medicine & Science in Sports, Vol. 28, No. 6The Effects of Altitude Training on Erythropoietic Response and Hematological Variables in Adult Athletes: A Narrative Review11 April 2018 | Frontiers in Physiology, Vol. 9Do male athletes with already high initial haemoglobin mass benefit from ‘live high-train low’ altitude training?5 November 2017 | Experimental Physiology, Vol. 103, No. 1Acute effects of repeated cycling sprints in hypoxia induced by voluntary hypoventilation14 October 2017 | European Journal of Applied Physiology, Vol. 117, No. 12Last Word on Viewpoint: Human skeletal muscle wasting in hypoxia: a matter of hypoxic dose?Gommaar D’Hulst and Louise Deldicque15 February 2017 | Journal of Applied Physiology, Vol. 122, No. 2Commentaries on Viewpoint: Human skeletal muscle wasting in hypoxia: a matter of hypoxic dose?15 February 2017 | Journal of Applied Physiology, Vol. 122, No. 2Last Word on Viewpoint: Time for a new metric for hypoxic dose?Laura A. Garvican-Lewis, Ken Sharpe, and Christopher J. Gore22 July 2016 | Journal of Applied Physiology, Vol. 121, No. 1 More from this issue > Volume 121Issue 1July 2016Pages 356-358 Copyright & PermissionsCopyright © 2016 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00460.2016PubMed27451276History Published online 22 July 2016 Published in print 1 July 2016 Metrics
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