Cardiovascular autonomic modulation and activity of carotid baroreceptors at altitude

Bernardi, Luciano, Passino, Claudio, Spadacini, Giammario, Calciati, Alessandro, Robergs, Robert A., Greene, Richard, Martignoni, Emilia, Anand, Inder, & Appenzeller, Otto (1998) Cardiovascular autonomic modulation and activity of carotid baroreceptors at altitude. Clinical Science, 95(5), pp. 565-573.

View at publisher

Abstract

  1. To assess the effects of acute exposure to high altitude on baroreceptor function in man we evaluated the effects of baroreceptor activation on R-R interval and blood pressure control at high altitude. We measured the low-frequency (LF) and high-frequency (HF) components in R-R, non-invasive blood pressure and skin blood flow, and the effect of baroreceptor modulation by 0.1-Hz sinusoidal neck suction. Ten healthy sea-level natives and three high-altitude native, long-term sea-level residents were evaluated at sea level, upon arrival at 4970 m and 1 week later.

  2. Compared with sea level, acute high altitude decreased R-R and increased blood pressure in all subjects [sea-level natives: R-R from 1002 ± 45 to 775 ± 57 ms, systolic blood pressure from 130 ± 3 to 150 ± 8 mmHg; high-altitude natives: R-R from 809 ± 116 to 749 ± 47 ms, systolic blood pressure from 110 ± 12 to 125 ± 11 mmHg (P < 0.05 for all)]. One week later systolic blood pressure was similar to values at sea level in all subjects, whereas R-R remained elevated in sea-level natives. The low-frequency power in R-R and systolic blood pressure increased in sea-level natives [R-R-LF from 47 ± 8 to 65 ± 10% (P < 0.05), systolic blood pressure-LF from 1.7 ± 0.3 to 2.6 ± 0.4 In-mmHg2 (P < 0.05)], but not in high-altitude natives (R-R-LF from 32 ± 13 to 38 ± 19%, systolic blood pressure-LF from 1.9 ± 0.5 to 1.7 ± 0.8 In-mmHg2). The R-R-HF decreased in sea-level natives but not in high-altitude natives, and no changes occurred in systolic blood pressure-HF. These changes remained evident 1 week later. Skin blood flow variability and its spectral components decreased markedly at high altitude in sea-level natives but showed no changes in high-altitude natives. Neck suction significantly increased the R-R- and systolic blood pressure-LF in all subjects at both sea level and high altitude.

  3. High altitude induces sympathetic activation in sea-level natives which is partially counteracted by active baroreflex. Despite long-term acclimatization at sea level, high-altitude natives also maintain active baroreflex at high altitude but with lower sympathetic activation, indicating a persisting high-altitude adaptation which may be genetic or due to baroreflex activity not completely lost by at least 1 year's sea-level residence.

Impact and interest:

75 citations in Scopus
Search Google Scholar™

Citation counts are sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

ID Code: 96937
Item Type: Journal Article
Refereed: Yes
Additional URLs:
Keywords: adrenergic system; adult; aged; altitude; altitude acclimatization; article; autonomic nervous system; blood pressure regulation; cardiovascular system; carotid sinus pressoreceptor; controlled study; diastolic blood pressure; human; human experiment; nor, Adult; Aged; Altitude; Blood Pressure; Cardiovascular System; Carotid Sinus; Electrocardiography; Heart Rate; Humans; Microcirculation; Middle Aged; Pressoreceptors; Signal Processing, Computer-Assisted; Skin; Suction; Sympathetic Nervous System; Time Factors
DOI: 10.1042/CS19980046
ISSN: 0143-5221
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Schools > School of Exercise & Nutrition Sciences
Deposited On: 21 Jul 2016 03:12
Last Modified: 21 Jul 2016 03:12

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page