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The independent effects of hypovolaemia and pulmonary vasoconstriction on ventricular function and exercise capacity during acclimatisation to 3800 m
- Source :
- The Journal of Physiology. 597:1059-1072
- Publication Year :
- 2018
- Publisher :
- Wiley, 2018.
-
Abstract
- KEY POINTS: We sought to determine the isolated and combined influence of hypovolaemia and hypoxic pulmonary vasoconstriction on the decrease in left ventricular (LV) function and maximal exercise capacity observed under hypobaric hypoxia. We performed echocardiography and maximal exercise tests at sea level (344 m), and following 5–10 days at the Barcroft Laboratory (3800 m; White Mountain, California) with and without (i) plasma volume expansion to sea level values and (ii) administration of the pulmonary vasodilatator sildenafil in a double‐blinded and placebo‐controlled trial. The high altitude‐induced reduction in LV filling and ejection was abolished by plasma volume expansion but to a lesser extent by sildenafil administration; however, neither intervention had a positive effect on maximal exercise capacity. Both hypovolaemia and hypoxic pulmonary vasoconstriction play a role in the reduction of LV filling at 3800 m, but the increase in LV filling does not influence exercise capacity at this moderate altitude. ABSTRACT: We aimed to determine the isolated and combined contribution of hypovolaemia and hypoxic pulmonary vasoconstriction in limiting left ventricular (LV) function and exercise capacity under chronic hypoxaemia at high altitude. In a double‐blinded, randomised and placebo‐controlled design, 12 healthy participants underwent echocardiography at rest and during submaximal exercise before completing a maximal test to exhaustion at sea level (SL; 344 m) and after 5–10 days at 3800 m. Plasma volume was normalised to SL values, and hypoxic pulmonary vasoconstriction was reversed by administration of sildenafil (50 mg) to create four unique experimental conditions that were compared with SL values: high altitude (HA), Plasma Volume Expansion (HA‐PVX), Sildenafil (HA‐SIL) and Plasma Volume Expansion with Sildenafil (HA‐PVX‐SIL). High altitude exposure reduced plasma volume by 11% (P
- Subjects :
- 0301 basic medicine
medicine.medical_specialty
Physiology
Hypovolemia
Reviews and research papers
03 medical and health sciences
0302 clinical medicine
medicine.artery
Internal medicine
Hypoxic pulmonary vasoconstriction
medicine
Humans
Ventricular Function
Exercise Tolerance
business.industry
Altitude
VO2 max
Stroke volume
Effects of high altitude on humans
Hypoxia (medical)
medicine.disease
Pulmonary hypertension
030104 developmental biology
Vasoconstriction
Pulmonary artery
Cardiology
medicine.symptom
business
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 14697793 and 00223751
- Volume :
- 597
- Database :
- OpenAIRE
- Journal :
- The Journal of Physiology
- Accession number :
- edsair.doi.dedup.....88cae0c7c98a45cdfc0058add92468f4