Changes

Some notes on If you're travelling to higher altitude training and or using [[Altitude Training]] to improve performance, it's worth understanding the science of how altitude effects athletes. The key takeaways are that acclimation takes about two weeks and most people will benefit from iron supplements, ideally starting weeks or months before altitude exposure. (Iron supplements should be taken under medical supervision and iron levels checked regularly. I use [https://www.walkinlab.com/ferritinserumtest.html Walk In Labs] to check my Serum Ferritin levels.)=The Effects of altitudeAltitude=

* Altitude is generally considered High altitude as 1500 to 3500m (5,000' to 11,500'), Very high altitude as 3500 to 5500m (11,500' to 18,000'), and Extreme altitude as above 5500m (18,000')<ref name="ParalikarParalikar2010"/>.* Rapid ascent from near sea level to above 2500m/8,000' can result in problems ranging from mild sickness to life-threatening Acute Mountain Sickness (AMS), but with gradual acclimation extreme altitudes can be tolerated<ref name="ParalikarParalikar2010"/>. * One "rule of thumb" is that above 3000m/10,000', you shouldn't sleep more than 300m/1,000' higher than the previous night<ref name="ParalikarParalikar2010"/>. * A key feature of acclimation to altitudes up to 5,000m/16,000' is an increase in breathing<ref name="West2006"/>. Other changes include an increase in heart rate, increase in blood pressure, increase in red blood cells, reduction in blood volume (increased urine output), increase in capillary density, and an increase in mitochondria and oxidative enzymes<ref name="Goldfarb-RumyantzevAlper2013"/>. However, the increase in capillary density might be at least partly due to a reduction in muscle fiber size<ref name="MizunoSavard2008"/>.* The human body adjusts to lower blood oxygen saturation in many ways. One adaption , and one key adaptation that is of interest to athletes is an increase in red blood cells, but the performance improvements from altitude training [[Altitude Training]] may come from other additional sources<ref name="Nonhematological"/><ref name="CounterpointGoreHopkins2005"/>. * The effects of altitude are non-linear. From sea level to Leadville (10,170 ft), your blood oxygen levels may drop 6% from 96% to 90%. Going up another 4,000 ft to Pike's Peak (14,110), blood oxygen levels may drop a further 8% to 82%. Running is harder at altitude as seen by the [[VO2max]] drop. At Leadville your [[VO2max]] may drop by ~15% (range 4-30%)* [[SpO2|SpO₂]] at altitude may be slightly misleading as the oxygen deliver to the muscles may be modified by O₂ dissociation curve shifts caused by changes in pH, PCO₂, and blood temperature<ref name="DempseyWagner1999"/>. However, [[SpO2|SpO₂]] is cheap and easy to monitor and should not be ignored. * There is great individual variability in the response to altitude<ref name="ChapmanStray-Gundersen1998"/>. Some studies have classified subjects as 'responders' and 'non-responders' due to the significance of this variability. This variability can change over time within an individual. I met someone in Tanzania who had been a porter on Kilimanjaro (19,334 ft) until he lost his ability to cope with the altitude.* Some variability may be due to differences in iron intake/availability. Low blood iron (serum ferritin < 20 ng/ml female, < 30 ng/ml male) may limit the body's ability to generate new red blood cells, which is part of the altitude adaptation. Studies in the USSR and CIS have shown genetic factors as well. * The effects of altitude are non-linear. From sea level to Leadville (10,170 ft), your blood oxygen levels drop 6% from 96% to 90%. Going up another 4,000 ft to Pike's Peak (14,110), blood oxygen levels drop a further 8% to 82%. * Running is harder at altitude as seen by the VO2max drop. At Leadville your VO2max will drop by ~15% (range 4-30%)* Athletes' performance may drop noticeably even at relatively low altitudes. At 1,900 ft, a 5 minute maximal exertion test was 6% (male) and 4% (female) lower than at sea level. * Athletes may suffer See below for more at altitude than sedentary people, and men more than womendetails on iron supplementation. * Generally , 'live high, train low' seems to work better than 'live high, train high'. [[Intermittent Hypoxic TrainingExposure]] may have additional benefits over other [[Altitude Training Approaches]].* Altitude acclimatization generally takes 1-time, with 2 weeksbeing a point of diminishing returns. This is based on a study of athletes traveling to 2340m/7,766' that showed a performance decrease of 26% on arrival, with they recovered by 6.0% after 7 days, another 5.7% after 14 days, but only another 1.4 weeks as the recommended minimum to achieve benefits% after 21 days<ref name="Schuler-2007"/>. These findings seem broadly similar for those sleeping in an altitude tent (normobaric hypoxia) <ref name="Townsend-2002"/>. * Training needs to be reduced at altitude, and this reduction can lead to detraining. 'Live high, train low' and [[Intermittent Hypoxic TrainingExposure]] help mitigate this problem. * Altitude acclimatization generally seems to last several weeks.* It is a myth that if you can't arrive at altitude with time to acclimate, it's best to arrive near within a day of your event. This is based on the idea that performance at altitude declines for a period before improving. However, research shows that the reduction in performance occurs immediately and improves gradually over time<ref name="SchulerThomsen2007"/>. At moderate altitudes (1700m/5,600') performance was better after just 18 hours compared with 6 hours<ref name="Weston-2001"/>.=Nutrition and Altitude=There's good evidence that nutrition is important for altitude acclimation, at least as far as iron goes. For other nutrients, the evidence is a little less clear. ==Iron==For adaptation to altitude, probably the most critical nutrient is Iron. Low iron stores can result in reduced adaptation to altitude<ref name="Stray-GundersenAlexander1992"/> and altitude training will reduce the body's stores of iron<ref name="Roberts-1992"/>. It's been suggested that iron supplementation may need to be started some months prior to the needed altitude acclimation due to the time taken for iron store to accumulate<ref name="Askew1995"/>, and six weeks may be insufficient time<ref name="ChapmanStray-Gundersen1998"/>. One study found that in a group of 178 athletes, iron stores (serum ferritin) reduced by 33% without supplementation, reduced by 14% with 105mg/day of iron and increased by 37% with 210 mg/day of iron<ref name="ConnorGovus2015"/>. Further, the non-supplemented athletes only increased hemoglobin mass by 1.1%, those on 105mg/day by 3.3% and those on 210 mg/day by 4.0%. The supplements were started one week before, and during, altitude exposure. The supplements were not given randomly but based on serum ferritin status. Those with levels above 100 ug/L were not supplemented, those with 30-100 ug/L were given 105 mg/day and those below 30 ug/L were given 210 mg/day. This suggests that even those with good iron status may need supplementation. However, that's a lot of iron, considering the RDA for men is only 8 mg/day and women 18 mg/day, and the tolerable upper intake is only 45 mg/day. Taking more than four times the tolerable upper intake is a little worrying, and the study made no mention of reported side effects. The study used a prolonged release supplement that included 105 mg iron with 1,000 mg Vitamin C (which can increase absorption of Iron) in a product called "Ferro Grad C."==Antioxidants==There's some indications that "live high, train low" may increase the need for antioxidants<ref name="PialouxMounier2008"/>. However, while some studies suggest that antioxidant supplementation might be beneficial<ref name="Tauler-2006"/><ref name="Goldfarb-2007"/>, it seems the preponderance of evidence is that antioxidant supplements may hinder recovery and adaptation to training stress<ref name="Gomez-Cabrera-2008"/><ref name="Peternelj-2011"/><ref name="Teixeira-2009"/>. ==Carbohydrate==It's unclear if the macronutrient mix of carbohydrate/protein/fat should be different at altitude, as most claims of the need for a high carbohydrate diet at altitude are based on sea level studies rather than any change due to altitude<ref name="MichalczykCzuba2016"/>. ==Vitamin D==There's no evidence for Vitamin D supplementation at altitude specifically, though there is the suggestion<ref name="MichalczykCzuba2016"/> that Vitamin D benefits might be particularly valuable as it may act as a vasodilator<ref name="Li-2004"/><ref name="Wacker-2013"/>. There's also the possibility that longer you have term (months) exposure to extreme altitude could result in bone loss<ref name="TanakaMinowa1992"/>. =Hydration and Altitude=Within 90 minutes of exposure to acclimatehigher altitudes, urine output increases<ref name="HildebrandtOttenbacher2000"/><ref name="Swenson-1995"/>, resulting in the loss of water and sodium<ref name="SwensonDuncan1995"/>. The diuretic effects of low pressure at altitude may be exacerbated by the bettertemperature, as cold conditions can result in "cold diuresis"<ref name="Scott-2004"/><ref name="HynynenIlmarinen1993"/>.One study suggests that hydration could exacerbate performance problems at altitude, but the study was short term (1 hour) and used dehydration that was not related to the altitude<ref name="ssCastellaniMuza2010"/>. While there is a net loss of water as a response to altitude, it's unclear if increased fluid intake would help or hinder performance. There is an argument that this loss of fluid is an important adaptation to altitude that concentrates the blood and reduces the demand on the heart<ref name="crowtherGrover-1986"/>* . There is some evidence that increased hydration does not increase the blood volume and may exacerbate fluid retention<ref name="Bärtsch-1991"/>. (Fluid retention is the build up of fluid between or inside the cells rather than in the blood.) There is further risk of [[Hyponatremia]] with excessive drinking, so caution is needed, and the advice to "drink to suggest thirst" would seem to remain valid. (Note that humans can adapt while people with kidney problems may be able to tolerate short durations at modest altitudes, the risks are unclear<ref name="LuksJohnson2008"/>.)=Assessing Altitude Impact=The Lake Louise Scoring System (LLSS) is used to assess the severity of AMS (Acute Mountain Sickness, or altitude sickness). The 2018 version of the LLSS scores headache, Gastrointestinal symptoms, fatigue, dizziness, and functional disruption to provide an overall assessment of AMS severity<ref name="RoachHackett2018"/>. (Sleep disruption was removed as it does not appear to survive be well corelated with AMS<ref name="SchulzHall2014"/>.) However, analysis has shown that a single question is just as effective as the LLSS<ref name="MeierCollet2017"/>. This is the Clinical Functional Score, which asks "overall if you had any symptoms, how did they affect your activity?", with possible answers of # "Not at all."# "Symptoms present but did not force any change in activity or itinerary."# "My symptoms forced me to stop the ascent or to go down on my own power."# "I had to be evacuated to a lower altitude ."=Effects of hypoxia=Low levels of SpO₂ effect brain functioning as shown in the following table<ref name="Anesthesia"/>.{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"! style="background-color: #F2F2F2;" |SpO₂! style="background-color: #F2F2F2;" |Description! style="background-color: #F2F2F2;" |Effect! style="background-color: #F2F2F2;" |Notes|-| style="background-color: #F9F9F9;" |100-80%| style="background-color: #F9F9F9;" |Mild Hypoxia| style="background-color: #F9F9F9;" |Normal brain functioning| style="background-color: #F9F9F9;" |This mild level of hypoxia does not affect the functioning of the brain, but some people can be sensitive enough to detect changes.|-| style="background-color: #F9F9F9;" |80-60%| style="background-color: #F9F9F9;" |Moderate Hypoxia| style="background-color: #F9F9F9;" |Decreasing brain function| style="background-color: #F9F9F9;" |Vision can be altered, including tunnel vision. Coordination is impaired in things like handwriting will deteriorate. Below 80% the skin may become blue (cyanosis). Mental functioning is impaired, sometimes creating euphoria or tranquility, including indifference to everything including pain. At this level some people become fixated on whatever they were doing when the hypoxia began, which can be dangerous. Memory and speech can also be impaired. There may be older treat visual hallucinations, feelings of depersonalization and even out of body experiences.|-| style="background-color: #F9F9F9;" |60-40%| style="background-color: #F9F9F9;" |Severe hypoxia| style="background-color: #F9F9F9;" |[[Muscle]] paralysis| style="background-color: #F9F9F9;" |Apparent unconsciousness.|-| style="background-color: #F9F9F9;" |<40%| style="background-color: #F9F9F9;" |Extreme hypoxia| style="background-color: #F9F9F9;" |Unconsciousness and eventually death| style="background-color: #F9F9F9;" ||}=Hypoxia and Altitude=The following table<ref name="Mehler1981"/> gives an idea of Everestdifferent [[SpO2|SpO₂]]levels at different altitudes.Intermittent Hypoxic Exposure can increase [[SpO2|SpO₂]]levels at a given altitude<ref name="EverestHetzlerStickley2009"/>, which are specified in the table below for some altitudes. However, the actual [[SpO2|SpO₂]] value at a given altitude will vary on many factors, so use this as a rough guide only. {| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"! style="background-color: #F2F2F2;" |'''Altitude(feet)'''! style="background-color: #F2F2F2;" |'''Altitude(meters)'''! style="background-color: #F2F2F2;" |'''Air Pressure(mmHg)'''! style="background-color: #F2F2F2;" |'''Oxygen Pressure(mmHg)'''! style="background-color: #F2F2F2;" |''' % of sea level Oxygen'''! style="background-color: #F2F2F2;" |'''Equivalent O2 partialpressure at sea level'''! style="background-color: #F2F2F2;" |'''SpO₂Unconditioned'''! style="background-color: #F2F2F2;"|'''SpO₂Conditioned'''|-| style="background-color: #F9F9F9;" |0| style="background-color: #F9F9F9;" |0| style="background-color: #F9F9F9;" |760| style="background-color: #F9F9F9;" |159| style="background-color: #F9F9F9;" |100| style="background-color: #F9F9F9;" |20.9| style="background-color: #F9F9F9;" |98%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |5,000| style="background-color: #F9F9F9;" |1,524| style="background-color: #F9F9F9;" |639| style="background-color: #F9F9F9;" |134| style="background-color: #F9F9F9;" |84| style="background-color: #F9F9F9;" |17.6| style="background-color: #F9F9F9;" |95%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |7,500| style="background-color: #F9F9F9;" |2,286| style="background-color: #F9F9F9;" |584| style="background-color: #F9F9F9;" |122| style="background-color: #F9F9F9;" |77| style="background-color: #F9F9F9;" |16.1| style="background-color: #F9F9F9;" |93%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |9,000| style="background-color: #F9F9F9;" |2,740| style="background-color: #F9F9F9;" |554| style="background-color: #F9F9F9;" |116| style="background-color: #F9F9F9;" |73| style="background-color: #F9F9F9;" |15.3| style="background-color: #F9F9F9;" |90.3% (+/-3.4%)| style="background-color: #F9F9F9;" |93.8% (+/-2%)|-| style="background-color: #F9F9F9;" |10,000| style="background-color: #F9F9F9;" |3,048| style="background-color: #F9F9F9;" |534| style="background-color: #F9F9F9;" |112| style="background-color: #F9F9F9;" |70| style="background-color: #F9F9F9;" |14.6| style="background-color: #F9F9F9;" |89%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |11,000| style="background-color: #F9F9F9;" |3,360| style="background-color: #F9F9F9;" |514| style="background-color: #F9F9F9;" |107| style="background-color: #F9F9F9;" |68| style="background-color: #F9F9F9;" |14.2| style="background-color: #F9F9F9;" |86.4 % (+/- 4.8%)| style="background-color: #F9F9F9;" |90.2% (+/-2.7%)|-| style="background-color: #F9F9F9;" |12,500| style="background-color: #F9F9F9;" |3,810| style="background-color: #F9F9F9;" |487| style="background-color: #F9F9F9;" |102| style="background-color: #F9F9F9;" |64| style="background-color: #F9F9F9;" |13.4| style="background-color: #F9F9F9;" |87%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |14,000| style="background-color: #F9F9F9;" |4,267| style="background-color: #F9F9F9;" |460| style="background-color: #F9F9F9;" |96| style="background-color: #F9F9F9;" |61| style="background-color: #F9F9F9;" |12.7| style="background-color: #F9F9F9;" |83%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |15,000| style="background-color: #F9F9F9;" |4,570| style="background-color: #F9F9F9;" |443| style="background-color: #F9F9F9;" |93| style="background-color: #F9F9F9;" |58| style="background-color: #F9F9F9;" |12.1| style="background-color: #F9F9F9;" |81.7% (+/-6%)| style="background-color: #F9F9F9;" |89.1% (+/-3%)|-| style="background-color: #F9F9F9;" |16,500| style="background-color: #F9F9F9;" |5,029| style="background-color: #F9F9F9;" |418| style="background-color: #F9F9F9;" |87| style="background-color: #F9F9F9;" |55| style="background-color: #F9F9F9;" |11.5| style="background-color: #F9F9F9;" |77%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |18,000| style="background-color: #F9F9F9;" |5,490| style="background-color: #F9F9F9;" |395| style="background-color: #F9F9F9;" |83| style="background-color: #F9F9F9;" |52| style="background-color: #F9F9F9;" |10.9| style="background-color: #F9F9F9;" || style="background-color: #F9F9F9;" |84.9% (+/-4%)|-| style="background-color: #F9F9F9;" |20,000| style="background-color: #F9F9F9;" |6,096| style="background-color: #F9F9F9;" |365| style="background-color: #F9F9F9;" |76| style="background-color: #F9F9F9;" |48| style="background-color: #F9F9F9;" |10.0| style="background-color: #F9F9F9;" |65%| style="background-color: #F9F9F9;" ||-| style="background-color: #F9F9F9;" |21,000| style="background-color: #F9F9F9;" |6,400| style="background-color: #F9F9F9;" |351| style="background-color: #F9F9F9;" |73| style="background-color: #F9F9F9;" |46| style="background-color: #F9F9F9;" |9.6| style="background-color: #F9F9F9;" || style="background-color: #F9F9F9;" |79.2% (+/-6%)|-| style="background-color: #F9F9F9;" |25,000| style="background-color: #F9F9F9;" |7,620| style="background-color: #F9F9F9;" |299| style="background-color: #F9F9F9;" |62| style="background-color: #F9F9F9;" |39| style="background-color: #F9F9F9;" |8.2| style="background-color: #F9F9F9;" |<60%| style="background-color: #F9F9F9;" ||}=See Also==

* [[Book Review – of Altitude Training and Athletic Performance]]* [[Intermittent Hypoxic TrainingExposure]] and [[Intermittent Hypoxic Training Exposure 101]]

=* [[Viagra, Exercise and Altitude]]=References==

<ref name="ssAnesthesia">anesthesia and hypoxia, Anesthesia !!website!!, http://www.sportsscientistsanesthesiaweb.comorg/2010hypoxia.php, 2018-05-31 !!access-date!!</ref><ref name="HetzlerStickley2009">Ronald K. Hetzler, Christopher D. Stickley, Iris F. Kimura, Michelle LaBotz, Andrew W. Nichols, Kenneth T. Nakasone, Ryan W. Sargent, Lawrence P.A. Burgess, The Effect of Dynamic Intermittent Hypoxic Conditioning on Arterial Oxygen Saturation, Wilderness & Environmental Medicine, volume 20, issue 1, 2009, pages 26–32, ISSN [http://www.worldcat.org/issn/10806032 10806032], doi [http://dx.doi.org/10.1580/0608-WEME-OR-218.1 10.1580/altitude08-arrivingWEME-andOR-adapting218.html Altitude in football1]</ref><ref name="Mehler1981">"The Pilot: When to arriveAn Air Breathing Mammal," Mehler, Stanley R. MD, Human Factors Bulletin, Flight Safety Foundation, 1981</ref><ref name="crowtherMeierCollet2017">David Meier, Tinh-Hai Collet, Isabella Locatelli, Jacques Cornuz, Bengt Kayser, David L. Simel, Claudio Sartori, Does This Patient Have Acute Mountain Sickness?, JAMA, volume 318, issue 18, 2017, pages 1810, ISSN [http://www.runningworldcat.org/issn/0098-7484 0098-blogs7484], doi [http://dx.doi.comorg/crowther10.1001/2007jama.2017.16192 10.1001/jama.2017.16192]</ref><ref name="SchulzHall2014">Christian Schulz, David P. Hall, Ian J. C. MacCormick, Alex T. Phythian-Adams, Nina M. Rzechorzek, David Hope-Jones, Sorrel Cosens, Stewart Jackson, Matthew G. D. Bates, David J. Collier, David A. Hume, Thomas Freeman, A. A. Roger Thompson, John Kenneth Baillie, Network Analysis Reveals Distinct Clinical Syndromes Underlying Acute Mountain Sickness, PLoS ONE, volume 9, issue 1, 2014, pages e81229, ISSN [http:/08/racing_at_high_altitude_a_mythwww.html Racing at high altitudeworldcat.org/issn/1932-6203 1932-6203], doi [http: a myth exposed//dx.doi.org/10.1371/journal.pone.0081229 10.1371/journal.pone.0081229]</ref><ref name="EverestRoachHackett2018">Robert C. Roach, Peter H. Hackett, Oswald Oelz, Peter Bärtsch, Andrew M. Luks, Martin J. MacInnis, J. Kenneth Baillie, Eric Achatz, Edi Albert, Jon S. Andrews, James D. Anholm, Mohammad Zahid Ashraf, Paul Auerbach, Buddha Basnyat, Beth A. Beidleman, R.R. Berendsen, Marc Moritz Berger, Konrad E. Bloch, Hermann Brugger, Annalisa Cogo, Ricardo Gonzalez Costa, Andrew Cumpstey, Allen Cymerman, Tadej Debevec, Catriona Duncan, David Dubowitz, Angela Fago, Michael Furian, Matt Gaidica, Prosenjit Ganguli, Michael P.W. Grocott, Debra Hammer, David Hall, David Hillebrandt, Matthias Peter Hilty, Gigugu Himashree, Benjamin Honigman, Ned Gilbert-Kawai, Bengt Kayser, Linda Keyes, Michael Koehle, Samantha Kohli, Arlena Kuenzel, Benjamin D. Levine, Mona Lichtblau, Jamie Macdonald, Monika Brodmann Maeder, Marco Maggiorini, Daniel Martin, Shigeru Masuyama, John McCall, Scott McIntosh, Gregoire Millet, Fernando Moraga, Craig Mounsey, Stephen R. Muza, Samuel Oliver, Qadar Pasha, Ryan Paterson, Lara Phillips, Aurélien Pichon, Philipp A. Pickerodt, Matiram Pun, Manjari Rain, Drummond Rennie, Ge Ri-Li, Steven Roy, Samuel Verges, Tatiana Batalha Cunha dos Santos, Robert B. Schoene, Otto D. Schoch, Surinderpal Singh, Talant Sooronbaev, Craig D. Steinback, Mike Stembridge, Glenn Stewart, Tsering Stobdan, Giacomo Strapazzon, Andrew W. Subudhi, Erik Swenson, A. A. Roger Thompson, Martha Tissot van Patot, Rosie Twomey, Silvia Ulrich, Nicolas Voituron, Dale R. Wagner, Shih-hao Wang, John B. West, Matt Wilkes, Gabriel Willmann, Michael Yaron, Ken Zafren, The 2018 Lake Louise Acute Mountain Sickness Score, High Altitude Medicine & Biology, volume 19, issue 1, 2018, pages 4–6, ISSN [http://www.zunivworldcat.netorg/issn/1557-8682 1557-8682], doi [http:/pub/Everest2dx.pdf Facts that Prove that Adaptation to Life at Extreme Altitudedoi.org/10.1089/ham.2017.0164 10.1089/ham.2017.0164]</ref><ref name="NonhematologicalWeston-2001">AR. Weston, G. Mackenzie, MA. Tufts, M. Mars, Optimal time of arrival for performance at moderate altitude (1700 m)., Med Sci Sports Exerc, volume 33, issue 2, pages 298-302, Feb 2001, PMID [http://www.ncbi.nlm.nih.gov/pubmed/17805094?ordinalpos11224821 11224821]</ref><ref name=2&itool"DempseyWagner1999">Jerome A. Dempsey, Peter D. Wagner, Exercise-induced arterial hypoxemia, Journal of Applied Physiology, volume 87, issue 6, 1999, pages 1997–2006, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/jappl.1999.87.6.1997 10.1152/jappl.1999.87.6.1997]</ref><ref name=EntrezSystem2"SchulerThomsen2007">B.PEntrezSchuler, J.PubmedJ.Pubmed_ResultsPanelThomsen, M.Pubmed_DefaultReportPanelGassmann, C.Pubmed_RVDocSum Nonhematological mechanisms Lundby, Timing the arrival at 2340 m altitude for aerobic performance, Scandinavian Journal of improved seaMedicine & Science in Sports, volume 17, issue 5, 2007, pages 588–594, ISSN [http://www.worldcat.org/issn/09057188 09057188], doi [http://dx.doi.org/10.1111/j.1600-0838.2006.00611.x 10.1111/j.1600-level performance after hypoxic exposure0838.2006.00611.x]</ref><ref name="CounterpointNonhematological">CJ. Gore, SA. Clark, PU. Saunders, Nonhematological mechanisms of improved sea-level performance after hypoxic exposure., Med Sci Sports Exerc, volume 39, issue 9, pages 1600-9, Sep 2007, doi [http://japdx.physiologydoi.org/cgi10.1249/mss.0b013e3180de49d3 10.1249/mss.0b013e3180de49d3], PMID [http:/content/fullwww.ncbi.nlm.nih.gov/99pubmed/517805094 17805094]</2055 ref><ref name="GoreHopkins2005">Christopher J Gore, Will G Hopkins, Counterpoint: Positive effects of intermittent hypoxia (live high:train low) on exercise performance are not mediated primarily by augmented red cell volume, Journal of Applied Physiology, volume 99, issue 5, 2005, pages 2055–2057, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/japplphysiol.00820.2005 10.1152/japplphysiol.00820.2005]</ref><ref name="ParalikarParalikar2010">SwapnilJ Paralikar, JagdishH Paralikar, High-altitude medicine, Indian Journal of Occupational and Environmental Medicine, volume 14, issue 1, 2010, pages 6, ISSN [http://www.worldcat.org/issn/0019-5278 0019-5278], doi [http://dx.doi.org/10.4103/0019-5278.64608 10.4103/0019-5278.64608]</ref><ref name="West2006">J. B. West, Human responses to extreme altitudes, Integrative and Comparative Biology, volume 46, issue 1, 2006, pages 25–34, ISSN [http://www.worldcat.org/issn/1540-7063 1540-7063], doi [http://dx.doi.org/10.1093/icb/icj005 10.1093/icb/icj005]</ref><ref name="Goldfarb-RumyantzevAlper2013">A. S. Goldfarb-Rumyantzev, S. L. Alper, Short-term responses of the kidney to high altitude in mountain climbers, Nephrology Dialysis Transplantation, volume 29, issue 3, 2013, pages 497–506, ISSN [http://www.worldcat.org/issn/0931-0509 0931-0509], doi [http://dx.doi.org/10.1093/ndt/gft051 10.1093/ndt/gft051]</ref><ref name="MizunoSavard2008">Masao Mizuno, Gabrielle K Savard, Nils-Holger Areskog, Carsten Lundby, Bengt Saltin, Skeletal Muscle Adaptations to Prolonged Exposure to Extreme Altitude: A Role of Physical Activity?, High Altitude Medicine & Biology, volume 9, issue 4, 2008, pages 311–317, ISSN [http://www.worldcat.org/issn/1527-0297 1527-0297], doi [http://dx.doi.org/10.1089/ham.2008.1009 10.1089/ham.2008.1009]</ref><ref name="HildebrandtOttenbacher2000">Wulf Hildebrandt, Andy Ottenbacher, Markus Schuster, Erik R. Swenson, Peter Bärtsch, Diuretic effect of hypoxia, hypocapnia, and hyperpnea in humans: relation to hormones and O2 chemosensitivity, Journal of Applied Physiology, volume 88, issue 2, 2000, pages 599–610, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/jappl.2000.88.2.599 10.1152/jappl.2000.88.2.599]</ref><ref name="SwensonDuncan1995">E. R. Swenson, T. B. Duncan, S. V. Goldberg, G. Ramirez, S. Ahmad, R. B. Schoene, Diuretic effect of acute hypoxia in humans: relationship to hypoxic ventilatory responsiveness and renal hormones, Journal of Applied Physiology, volume 78, issue 2, 1995, pages 377–383, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/jappl.1995.78.2.377 10.1152/jappl.1995.78.2.377]</ref><ref name="Scott-2004">D. Scott, JA. Rycroft, J. Aspen, C. Chapman, B. Brown, The effect of drinking tea at high altitude on hydration status and mood., Eur J Appl Physiol, volume 91, issue 4, pages 493-8, Apr 2004, doi [http://dx.doi.org/10.1007/s00421-003-1015-z 10.1007/s00421-003-1015-z], PMID [http://www.ncbi.nlm.nih.gov/pubmed/14872247 14872247]</ref><ref name="HynynenIlmarinen1993">M. Hynynen, R. Ilmarinen, I. Tikkanen, F. Fyhrquist, Plasma atrial natriuretic factor during cold-induced diuresis, European Journal of Applied Physiology and Occupational Physiology, volume 67, issue 3, 1993, pages 286–289, ISSN [http://www.worldcat.org/issn/0301-5548 0301-5548], doi [http://dx.doi.org/10.1007/BF00864230 10.1007/BF00864230]</ref><ref name="Swenson-1995">ER. Swenson, TB. Duncan, SV. Goldberg, G. Ramirez, S. Ahmad, RB. Schoene, Diuretic effect of acute hypoxia in humans: relationship to hypoxic ventilatory responsiveness and renal hormones., J Appl Physiol (1985), volume 78, issue 2, pages 377-83, Feb 1995, doi [http://dx.doi.org/10.1152/jappl.1995.78.2.377 10.1152/jappl.1995.78.2.377], PMID [http://www.ncbi.nlm.nih.gov/pubmed/7759405 7759405]</ref><ref name="CastellaniMuza2010">John W. Castellani, Stephen R. Muza, Samuel N. Cheuvront, Ingrid V. Sils, Charles S. Fulco, Robert W. Kenefick, Beth A. Beidleman, Michael N. Sawka, Effect of hypohydration and altitude exposure on aerobic exercise performance and acute mountain sickness, Journal of Applied Physiology, volume 109, issue 6, 2010, pages 1792–1800, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/japplphysiol.00517.2010 10.1152/japplphysiol.00517.2010]</ref><ref name="LuksJohnson2008">A. M. Luks, R. J. Johnson, E. R. Swenson, Chronic Kidney Disease at High Altitude, Journal of the American Society of Nephrology, volume 19, issue 12, 2008, pages 2262–2271, ISSN [http://www.worldcat.org/issn/1046-6673 1046-6673], doi [http://dx.doi.org/10.1681/ASN.2007111199 10.1681/ASN.2007111199]</ref><ref name="Grover-1986">RF. Grover, JV. Weil, JT. Reeves, Cardiovascular adaptation to exercise at high altitude., Exerc Sport Sci Rev, volume 14, pages 269-302, 1986, PMID [http://www.ncbi.nlm.nih.gov/pubmed/3525187 3525187]</ref><ref name="Bärtsch-1991">P. Bärtsch, N. Pfluger, M. Audétat, S. Shaw, P. Weidmann, P. Vock, W. Vetter, D. Rennie, O. Oelz, Effects of slow ascent to 4559 M on fluid homeostasis., Aviat Space Environ Med, volume 62, issue 2, pages 105-10, Feb 1991, PMID [http://www.ncbi.nlm.nih.gov/pubmed/1825779 1825779]</ref><ref name="ChapmanStray-Gundersen1998">Robert F. Chapman, James Stray-Gundersen, Benjamin D. Levine, Individual variation in response to altitude training, Journal of Applied Physiology, volume 85, issue 4, 1998, pages 1448–1456, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/jappl.1998.85.4.1448 10.1152/jappl.1998.85.4.1448]</ref> <ref name="Schuler-2007">B. Schuler, JJ. Thomsen, M. Gassmann, C. Lundby, Timing the arrival at 2340 m altitude for aerobic performance., Scand J Med Sci Sports, volume 17, issue 5, pages 588-94, Oct 2007, doi [http://dx.doi.org/10.1111/j.1600-0838.2006.00611.x 10.1111/j.1600-0838.2006.00611.x], PMID [http://www.ncbi.nlm.nih.gov/pubmed/17316377 17316377]</ref><ref name="Townsend-2002">NE. Townsend, CJ. Gore, AG. Hahn, MJ. McKenna, RJ. Aughey, SA. Clark, T. Kinsman, JA. Hawley, CM. Chow, Living high-training low increases hypoxic ventilatory response of well-trained endurance athletes., J Appl Physiol (1985), volume 93, issue 4, pages 1498-505, Oct 2002, doi [http://dx.doi.org/10.1152/japplphysiol.00381.2002 10.1152/japplphysiol.00381.2002], PMID [http://www.ncbi.nlm.nih.gov/pubmed/12235052 12235052]</ref><ref name="MichalczykCzuba2016">Małgorzata Michalczyk, Miłosz Czuba, Grzegorz Zydek, Adam Zając, Józef Langfort, Dietary Recommendations for Cyclists during Altitude Training, Nutrients, volume 8, issue 6, 2016, pages 377, ISSN [http://www.worldcat.org/issn/2072-6643 2072-6643], doi [http://dx.doi.org/10.3390/nu8060377 10.3390/nu8060377]</ref> <ref name="PialouxMounier2008">V Pialoux, R Mounier, E Rock, A Mazur, L Schmitt, J-P Richalet, P Robach, J Brugniaux, J Coudert, N Fellmann, Effects of the 'live high–train low' method on prooxidant/antioxidant balance on elite athletes, European Journal of Clinical Nutrition, volume 63, issue 6, 2008, pages 756–762, ISSN [http://www.worldcat.org/issn/0954-3007 0954-3007], doi [http://dx.doi.org/10.1038/ejcn.2008.30 10.1038/ejcn.2008.30]</ref><ref name="Tauler-2006">P. Tauler, A. Aguiló, I. Gimeno, E. Fuentespina, JA. Tur, A. Pons, Response of blood cell antioxidant enzyme defences to antioxidant diet supplementation and to intense exercise., Eur J Nutr, volume 45, issue 4, pages 187-95, Jun 2006, doi [http://dx.doi.org/10.1007/s00394-005-0582-7 10.1007/s00394-005-0582-7], PMID [http://www.ncbi.nlm.nih.gov/pubmed/16365696 16365696]</ref><ref name="Goldfarb-2007">AH. Goldfarb, MJ. McKenzie, RJ. Bloomer, Gender comparisons of exercise-induced oxidative stress: influence of antioxidant supplementation., Appl Physiol Nutr Metab, volume 32, issue 6, pages 1124-31, Dec 2007, doi [http://dx.doi.org/10.1139/H07-078 10.1139/H07-078], PMID [http://www.ncbi.nlm.nih.gov/pubmed/18059586 18059586]</ref><ref name="Gomez-Cabrera-2008">MC. Gomez-Cabrera, E. Domenech, M. Romagnoli, A. Arduini, C. Borras, FV. Pallardo, J. Sastre, J. Viña, Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance., Am J Clin Nutr, volume 87, issue 1, pages 142-9, Jan 2008, doi [http://dx.doi.org/10.1093/ajcn/87.1.142 10.1093/ajcn/87.1.142], PMID [http://www.ncbi.nlm.nih.gov/pubmed/18175748 18175748]</ref><ref name="Peternelj-2011">TT. Peternelj, JS. Coombes, Antioxidant supplementation during exercise training: beneficial or detrimental?, Sports Med, volume 41, issue 12, pages 1043-69, Dec 2011, doi [http://dx.doi.org/10.2165/11594400-000000000-00000 10.2165/11594400-000000000-00000], PMID [http://www.ncbi.nlm.nih.gov/pubmed/22060178 22060178]</ref><ref name="Teixeira-2009">VH. Teixeira, HF. Valente, SI. Casal, AF. Marques, PA. Moreira, Antioxidants do not prevent postexercise peroxidation and may delay muscle recovery., Med Sci Sports Exerc, volume 41, issue 9, pages 1752-60, Sep 2009, doi [http://dx.doi.org/10.1249/MSS.0b013e31819fe8e3 10.1249/MSS.0b013e31819fe8e3], PMID [http://www.ncbi.nlm.nih.gov/pubmed/19657294 19657294]</ref><ref name="Stray-GundersenAlexander1992">J. Stray-Gundersen, C. Alexander, A. Hochstein, D. deLemos, B D Levine, FAILURE OF RED CELL VOLUME TO INCREASE TO ALTITUDE EXPOSURE IN IRON DEFICIENT RUNNERS, Medicine & Science in Sports & Exercise, volume 24, issue Supplement, 1992, pages S90, ISSN [http://www.worldcat.org/issn/0195-9131 0195-9131], doi [http://dx.doi.org/10.1249/00005768-199205001-00541 10.1249/00005768-199205001-00541]</ref><ref name="Roberts-1992">D. Roberts, DJ. Smith, Training at moderate altitude: iron status of elite male swimmers., J Lab Clin Med, volume 120, issue 3, pages 387-91, Sep 1992, PMID [http://www.ncbi.nlm.nih.gov/pubmed/1517685 1517685]</ref><ref name="Askew1995">E W Askew, Environmental and physical stress and nutrient requirements, The American Journal of Clinical Nutrition, volume 61, issue 3, 1995, pages 631S–637S, ISSN [http://www.worldcat.org/issn/0002-9165 0002-9165], doi [http://dx.doi.org/10.1093/ajcn/61.3.631S 10.1093/ajcn/61.3.631S]</ref><ref name="ChapmanStray-Gundersen1998">Robert F. Chapman, James Stray-Gundersen, Benjamin D. Levine, Individual variation in response to altitude training, Journal of Applied Physiology, volume 85, issue 4, 1998, pages 1448–1456, ISSN [http://www.worldcat.org/issn/8750-7587 8750-7587], doi [http://dx.doi.org/10.1152/jappl.1998.85.4.1448 10.1152/jappl.1998.85.4.1448]</ref><ref name="ConnorGovus2015">James R. Connor, Andrew D. Govus, Laura A. Garvican-Lewis, Chris R. Abbiss, Peter Peeling, Christopher J. Gore, Pre-Altitude Serum Ferritin Levels and Daily Oral Iron Supplement Dose Mediate Iron Parameter and Hemoglobin Mass Responses to Altitude Exposure, PLOS ONE, volume 10, issue 8, 2015, pages e0135120, ISSN [http://www.worldcat.org/issn/1932-6203 1932-6203], doi [http://dx.doi.org/10.1371/journal.pone.0135120 10.1371/journal.pone.0135120]</ref><ref name="Li-2004">YC. Li, G. Qiao, M. Uskokovic, W. Xiang, W. Zheng, J. Kong, Vitamin D: a negative endocrine regulator of the renin-angiotensin system and blood pressure., J Steroid Biochem Mol Biol, volume 89-90, issue 1-5, pages 387-92, May 2004, doi [http://dx.doi.org/10.1016/j.jsbmb.2004.03.004 10.1016/j.jsbmb.2004.03.004], PMID [http://www.ncbi.nlm.nih.gov/pubmed/15225806 15225806]</ref><ref name="Wacker-2013">M. Wacker, MF. Holick, Vitamin D - effects on skeletal and extraskeletal health and the need for supplementation., Nutrients, volume 5, issue 1, pages 111-48, Jan 2013, doi [http://dx.doi.org/10.3390/nu5010111 10.3390/nu5010111], PMID [http://www.ncbi.nlm.nih.gov/pubmed/23306192 23306192]</ref><ref name="TanakaMinowa1992">Hiroyuki Tanaka, Keiji Minowa, Tetsuya Satoh, Tatsuya Koike, Bone atrophy at high altitude, Journal of Bone and Mineral Metabolism, volume 10, issue 1, 1992, pages 31–36, ISSN [http://www.worldcat.org/issn/0914-8779 0914-8779], doi [http://dx.doi.org/10.1007/BF02383459 10.1007/BF02383459]</ref>