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==Viagra and Performance==Viagra (the brand name for Sildenafil) has been shown to help with the effects of altitude. Some studies<ref name="ViagraMaxEverestGhofrani-2004"/><ref name="ViagraMax5000mFaoroLamotte2007"/><ref name="ViagraMax40mgPerimenis2005"/> have shown that Viagra increases the maximum exercise capacity at altitude. One study<ref name="RespondersHsu-2006"/> showed that for some trained cyclists a single dose of Viagra 1 hour before exercise produced a significant improvement (39%) in sub-maximal performance in altitude (12,700 ft) while others did not experience a worthwhile improvement (1%). However, another study<ref name="ViagraSixDaysRichalet-2005"/> supplied Viagra for 6 days, and the benefits took several days to kick in. Other studies<ref name="ViagraMaxEverestGhofrani-2004"/> have shown benefits from a single dose 2 hours before exercise. A study of 20 male and 15 female trained athletes performing a 6 Km time trial at a simulated 12,700ft altitude showed only a single male athlete with improved performance, so individuality may be a factor<ref name="JacobsKressler2011"/>. ==Altitude Sickness==Long term use of Viagra has been shown<ref name="ViagraHAPHAldashev-2005"/> reduce the impact of altitude. Subjects were given Viagra every 8 hours for 12 weeks inhibited a particular type of altitude sickness (high altitude pulmonary arterial hypertension or HAPH). Viagra also improved the distance the subjects could walk in 6 minutes. Altitude sickness can lead to a potentially lethal condition called "High-Altitude Pulmonary Edema" (HAPE). Viagra is considered<ref name="ViagraHAPEHypothesesKleinsasser-2002"/> a viable treatment for HAPE, and is being used in some situations<ref name="ViagraHAPETreatmentFagenholzGutman2007"/>. A review of 5 studies found that Viagra reduced pulmonary systolic arterial pressure, but did not improve oxygen saturation or Acute Mountain Sickness scores<ref name="XuLiu2014"/>. The use of Viagra as a preventative in healthy subjects with no history of HAPE may not be justified<ref name="BatesThompson2011"/>. The best treatment for Altitude Sickness is decent, but in the event that decent is dangerous, Viagra may be useful. ==Side Effects of Viagra==Viagra can cause headaches<ref name="ViagraHAPHAldashev-2005"/> at altitude or at sea level<ref name="RespondersHsu-2006"/>. No other side effects were noted in any of the altitude studies. Viagra is a vasodilator which can cause systemic hypotension (low blood pressure), especially given with nifedipine, but a review of 56 subjects administered Viagra for altitude sickness did not have this problem<ref name="JonesStokes2013"/>. The primary use of Viagra for Erectile Dysfunction does raise some questions about other possible side effects, as well as being a source of endless jokes. However, background reading suggests that Viagra does not result in unwanted erections and requires physical or mental stimulation. In the treatment of ED, noted side effects included headache, flushing, dyspepsia, nasal congestion and impaired vision, including photophobia and blurred vision<ref name="ViagraSideEffect"/>.=Viagra and Doping=At the time of writing, the World Anti-Doping Agency has not banned Viagra (Sildenafil), but you should check before using Viagra (or any other medication) before taking it. [https://www.wada-ama.org/ https://www.wada-ama.org/] =What this means==Viagra is a prescription medication and should only be taken under medical supervision. I believe that self-medication is foolish and I urge you to talk to your doctor if you think Viagra would help. The performance benefits of Viagra at altitude are might be significant enough to warrant further investigation if you are competitive or know you have problems dealing with altitude. , but personally I would also consider talking to my doctor about a only use Viagra prescription if I was going to be at in as a remote location at high treatment for altitudesickness. ==See Also==

 ==References==

<ref name="RespondersHsu-2006">AR. Hsu, KE. Barnholt, NK. Grundmann, JH. Lin, SW. McCallum, AL. Friedlander, Sildenafil improves cardiac output and exercise performance during acute hypoxia, but not normoxia ., J Appl Physiol (1985), volume 100, issue 6, pages 2031-40, Jun 2006, doi [http://japdx.physiologydoi.org/content10.1152/japplphysiol.00806.2005 10.1152/100japplphysiol.00806.2005], PMID [http:/6/2031www.ncbi.nlm.nih.fullgov/pubmed/16455814 16455814]</ref><ref name="ViagraMaxEverestGhofrani-2004">HA. Ghofrani, F. Reichenberger, MG. Kohstall, EH. Mrosek, T. Seeger, H. Olschewski, W. Seeger, F. Grimminger, Sildenafil Increased Exercise Capacity increased exercise capacity during Hypoxia hypoxia at Low Altitudes low altitudes and at Mount Everest Base Camp base camp: a randomized, double-blind, placebo-controlled crossover trial., Ann Intern Med, volume 141, issue 3, pages 169-77, Aug 2004, PMID [http://www.annalsncbi.orgnlm.nih.gov/content/141/3pubmed/169.short15289213 15289213]</ref><ref name="ViagraMax5000mFaoroLamotte2007">Mary Ann LiebertVitalie Faoro, Michel Lamotte, Gael Deboeck, Adriana Pavelescu, Sandrine Huez, Hervé Guenard, Inc. Jean- Benoît Martinot, Robert Naeije, Effects of Sildenafil on Exercise Capacity in Hypoxic Normal Subjects, High Altitude Medicine & Biology - , volume 8(, issue 2):155 , 2007, pages 155–163, ISSN [http://www.liebertonlineworldcat.comorg/issn/1527-0297 1527-0297], doi[http:/abs/dx.doi.org/10.1089/ham.2007.1058 10.1089/ham.2007.1058]</ref><ref name="ViagraMax40mgPerimenis2005">Informa Healthcare Petros Perimenis, Sildenafil for the treatment of altitude- induced hypoxaemia, Expert Opinion on Pharmacotherapy - , volume 6(, issue 5), 2005, pages 835–837, ISSN [http:835 //www.worldcat.org/issn/1465-6566 1465- Summary 6566], doi [http://informahealthcaredx.com/doi.org/abs10.1517/14656566.6.5.835 10.1517/14656566.6.5.835]</ref><ref name="ViagraHAPHAldashev-2005">AA. Aldashev, BK. Kojonazarov, TA. Amatov, TM. Sooronbaev, MM. Mirrakhimov, NW. Morrell, J. Wharton, MR. Wilkins, Phosphodiesterase type 5 and high altitude pulmonary hypertension -- Aldashev et al. , Thorax, volume 60 (, issue 8): , pages 683 -- Thorax 7, Aug 2005, doi [http://thoraxdx.bmjdoi.comorg/content10.1136/60thx.2005.041954 10.1136/thx.2005.041954], PMID [http:/8/683www.ncbi.nlm.nih.abstractgov/pubmed/16061711 16061711]</ref><ref name="ViagraSixDaysRichalet-2005">JP. Richalet, P. Gratadour, P. Robach, I. Pham, M. Déchaux, A. Joncquiert-Latarjet, P. Mollard, J. Brugniaux, J. Cornolo, Sildenafil Inhibits Altitudeinhibits altitude-induced Hypoxemia hypoxemia and Pulmonary Hypertension -- Richalet et alpulmonary hypertension. , Am J Respir Crit Care Med, volume 171 (, issue 3): , pages 275 -- American Journal of Respiratory and Critical Care Medicine 81, Feb 2005, doi [http://ajrccmdx.atsjournalsdoi.org/cgi10.1164/rccm.200406-804OC 10.1164/contentrccm.200406-804OC], PMID [http:/abstract/171www.ncbi.nlm.nih.gov/3pubmed/27515516532 15516532]</ref><ref name="ViagraHAPEHypothesesKleinsasser-2002">A. Kleinsasser, A. Loeckinger, Are sildenafil and theophylline effective in the prevention of high-altitude pulmonary edema? , Med Hypotheses, volume 59, issue 2, pages 223-5, Aug 2002, PMID [http://www.medical-hypothesesncbi.nlm.nih.comgov/article/S0306-9877%2802%2900198-6pubmed/abstract12208214 12208214]</ref> <ref name="ViagraHAPETreatmentFagenholzGutman2007">Mary Ann LiebertPeter J. Fagenholz, Jonathan A. Gutman, Alice F. Murray, IncN. - Stuart Harris, Treatment of High Altitude Pulmonary Edema at 4240 m in Nepal, High Altitude Medicine & Biology - , volume 8(, issue 2):139 , 2007, pages 139–146, ISSN [http://www.liebertonlineworldcat.comorg/issn/1527-0297 1527-0297], doi[http:/abs/dx.doi.org/10.1089/ham.2007.3055 10.1089/ham.2007.3055]</ref>