{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,29]],"date-time":"2026-03-29T09:54:39Z","timestamp":1774778079492,"version":"3.50.1"},"reference-count":42,"publisher":"SAGE Publications","issue":"2","license":[{"start":{"date-parts":[[2016,6,1]],"date-time":"2016-06-01T00:00:00Z","timestamp":1464739200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Wilderness &amp; Environmental Medicine"],"published-print":{"date-parts":[[2016,6]]},"abstract":"<jats:sec><jats:title>Objective<\/jats:title><jats:p> Hypobaric hypoxia decreases exercise capacity and causes hypoxic pulmonary vasoconstriction and pulmonary hypertension. The phosphodiesterase-5 inhibitor sildenafil is a pulmonary vasodilator that may improve exercise capacity at altitude. We aimed to determine whether sildenafil improves exercise capacity, measured as maximal oxygen consumption (peak V\u0307o<jats:sub>2<\/jats:sub>), at moderate altitude in adults 60 years or older. <\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p> The design was a randomized, double-blind, placebo-controlled, crossover study. After baseline cardiopulmonary exercise testing at 1400 m, 12 healthy participants (4 women) aged 60 years or older, who reside permanently at approximately 1400 m and are regularly active in self-propelled mountain recreation above 2000 m, performed maximal cardiopulmonary cycle exercise tests in a hypobaric chamber at a simulated altitude of 2750 m after ingesting sildenafil and after ingesting a placebo. <\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p> After placebo, mean peak V\u0307o<jats:sub>2<\/jats:sub> was significantly lower at 2750 m than 1400 m: 37.0 mL \u00b7 kg<jats:sup>-1<\/jats:sup> \u00b7 min<jats:sup>-1<\/jats:sup> (95% CI, 32.7 to 41.3) vs 39.1 mL \u00b7 kg<jats:sup>-1<\/jats:sup> \u00b7 min<jats:sup>-1<\/jats:sup> (95% CI, 33.5 to 44.7; P = .020). After placebo, there was no difference in heart rate (HR) or maximal workload at either altitude ( z = 0.182; P = .668, respectively). There was no difference between sildenafil and placebo at 2750 m in peak V\u0307o<jats:sub>2<\/jats:sub> ( P = .668), O<jats:sub>2<\/jats:sub> pulse ( P = .476), cardiac index ( P = .143), stroke volume index ( z = 0.108), HR ( z = 0.919), or maximal workload ( P = .773). Transthoracic echocardiography immediately after peak exercise at 2750 m showed tricuspid annular plane systolic velocity was significantly higher after sildenafil than after placebo ( P = .019), but showed no difference in tricuspid annular plane systolic excursion ( P = .720). <\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p> Sildenafil (50 mg) did not improve exercise capacity in adults 60 years or older at moderate altitude in our study. This might be explained by a \u201cdosing effect\u201d or insufficiently high altitude. <\/jats:p><\/jats:sec>","DOI":"10.1016\/j.wem.2016.01.006","type":"journal-article","created":{"date-parts":[[2016,5,1]],"date-time":"2016-05-01T05:46:35Z","timestamp":1462081595000},"page":"307-315","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":11,"title":["Sildenafil and Exercise Capacity in the Elderly at Moderate Altitude"],"prefix":"10.1177","volume":"27","author":[{"given":"George W.","family":"Rodway","sequence":"first","affiliation":[{"name":"University of Utah School of Nursing, Salt Lake City, UT (Dr Rodway)"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anne J.","family":"Lovelace","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael J.","family":"Lanspa","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Scott E.","family":"McIntosh","sequence":"additional","affiliation":[{"name":"Division of Emergency Medicine (Dr McIntosh)"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"James","family":"Bell","sequence":"additional","affiliation":[{"name":"Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT"},{"name":"Hyperbaric Medicine (Mr Bell), LDS Hospital, Salt Lake City, UT"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ben","family":"Briggs","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lindell K.","family":"Weaver","sequence":"additional","affiliation":[{"name":"Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT"},{"name":"Department of Pulmonary and Critical Care (Dr Weaver)"},{"name":"School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Frank","family":"Yanowitz","sequence":"additional","affiliation":[{"name":"and ECG Services and Cardiac Rehabilitation (Dr Yanowitz)"},{"name":"School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Colin K.","family":"Grissom","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2016,6,1]]},"reference":[{"key":"bibr1-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCULATIONAHA.106.650796"},{"key":"bibr2-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2013.1110"},{"key":"bibr3-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-007-0457-0"},{"key":"bibr4-jwem201601006","volume-title":"Pulmonary System Adaptations: Limitations to Exercise","author":"Babcock M.A.","year":"1994"},{"key":"bibr5-jwem201601006","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-141-3-200408030-00005"},{"key":"bibr6-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00806.2005"},{"key":"bibr7-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-011-1930-3"},{"key":"bibr8-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1161\/hc2901.093117"},{"key":"bibr9-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1164\/rccm.200406-804OC"},{"key":"bibr10-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1183\/09031936.00124007"},{"key":"bibr11-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2011.0007"},{"key":"bibr12-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2007.1058"},{"key":"bibr13-jwem201601006","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2005.6.43"},{"key":"bibr14-jwem201601006","unstructured":"US Department of Health and Human Services, Administration for Community Living. 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