Abstract:
: Background: Perfusion of intrapulmonary arteriovenous anastomoses (IPAVA) is increased during exercise and in hypoxia and is associated with variations in oxygen saturation (SPO2), resulting in blood bypassing the pulmonary microcirculation. Sildenafil is a pulmonary vasodilator that improves SPO2 and endurance performance in hypoxia. The purpose of this study was to determine if 50 mg sildenafil would reduce IPAVA perfusion (QIPAVA) and if the decrement in maximal exercise capacity (VO2max) in hypoxia is related to QIPAVA. We hypothesized that during progressive levels of hypoxia at rest (FIO2 = 0.21, 0.14, 0.12), sildenafil would increase SPO2 and reduce bubble score (estimate of QIPAVA) compared to placebo, and that the decrement in VO2max in hypoxia would be positively correlated with bubble score at rest in hypoxia. Materials and Methods: Fourteen endurance-trained men performed a graded maximal exercise test at sea level and at a simulated altitude of 3000 m, followed by two experimental visits where, after randomly ingesting sildenafil or placebo, they underwent agitated saline contrast echocardiography during progressive levels of hypoxia at rest. Results: All participants experienced a decrement in power output in hypoxia that ranged from 9% to 19% lower than sea level values. Compared to normoxia, bubble score increased significantly in hypoxia (p < 0.001) with no effect of sildenafil (p = 0.580). There was a negative correlation between SPO2 and bubble score (p < 0.001). The decrement in peak power output at VO2max in hypoxia was unrelated to IPAVA perfusion in resting hypoxia (p = 0.32). Several participants demonstrated QIPAVA greater than zero in room air, indicating that arterial hypoxemia may not be the sole mechanism for QIPAVA. Conclusion: These results indicate that the VO2max decrement caused by hypoxia is not related to QIPAVA and that sildenafil does not improve VO2max in hypoxia through modulation of QIPAVA.
journal_name
High Alt Med Bioljournal_title
High altitude medicine & biologyauthors
Carter EA,Koch S,O'Donovan JP,Sheel AW,Milsom WK,Koehle MSdoi
10.1089/ham.2019.0051subject
Has Abstractpub_date
2019-12-01 00:00:00pages
399-406issue
4eissn
1527-0297issn
1557-8682journal_volume
20pub_type
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
pub_type: 杂志文章,评审
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journal_title:High altitude medicine & biology
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更新日期:2019-03-01 00:00:00
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2008.1035
更新日期:2008-01-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章,评审
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2016.0040
更新日期:2016-09-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
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更新日期:2020-12-01 00:00:00
abstract::The present study compares the changes in ventilation in response to sustained hypobaric hypoxia and acute normobaric hypoxia between subjects susceptible to high altitude pulmonary edema (HAPE-S) and control subjects (C-S). Seven HAPE-S and five C-S were exposed to simulated high altitude of 4000 m for 23 h in a hypo...
journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2009.1057
更新日期:2010-10-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
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更新日期:2011-01-01 00:00:00
abstract::West, John B. Are permanent residents of high altitude fully adapted to their hypoxic environment? High Alt Med Biol. 18:135-139, 2017.-Millions of people live permanently at high altitude and many have been there for generations. It is sometimes claimed that these people have completely adapted to their environment, ...
journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
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更新日期:2019-06-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2012.1071
更新日期:2013-03-01 00:00:00
abstract::Álvarez-Herms, Jesús, Sonia Julià-Sánchez, Hannes Gatterer, Francisco Corbi, Gines Viscor, and Martin Burtscher. Effects of a single power strength training session on heart rate variability when performed at different simulated altitudes. High Alt Med Biol. 21:292-296, 2020. Background: ...
journal_title:High altitude medicine & biology
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abstract::Appointing physiological function to specific genetic determinants requires a systems physiologist to consider ways of assessing precise phenotypic mechanisms. The integration of ventilation, metabolism and thermoregulation, for example, is very complex and may differ among small and large mammalian species. This chal...
journal_title:High altitude medicine & biology
pub_type: 杂志文章,评审
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更新日期:2001-07-01 00:00:00
abstract::The influence of oxygen pressure on placental and villous vascular development is reviewed and considered relative to the natural experiment afforded by residence at high altitude. Data obtained from normal high altitude pregnancies are compared with those from IUGR and preeclampsia, conditions believed to be caused b...
journal_title:High altitude medicine & biology
pub_type: 杂志文章,评审
doi:10.1089/152702903322022785
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abstract::Alarcón-Yaquetto, Dulce E., Lidia Caballero, and Gustavo F. Gonzales. Association between plasma N-acylethanolamides and high hemoglobin concentration in Southern Peruvian highlanders. High Alt Med Biol 18:322-329, 2017.-High-altitude (HA) hypoxia is a stressful condition endured by organisms through different mechani...
journal_title:High altitude medicine & biology
pub_type: 杂志文章
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更新日期:2017-12-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章,meta分析,评审
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更新日期:2012-06-01 00:00:00
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journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2012.1091
更新日期:2013-12-01 00:00:00
abstract::Climbers who have suffered a previous episode of high altitude pulmonary edema (HAPE) are at significantly increased risk of developing it again on return to high altitude. In spite of the high mortality associated with HAPE, some climbers are willing to take this risk in order to summit the tallest mountains in the w...
journal_title:High altitude medicine & biology
pub_type: 杂志文章
doi:10.1089/ham.2008.1094
更新日期:2009-10-01 00:00:00