Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude

R. S. Mazzeo, J. D. Carroll, G. E. Butterfield, B. Braun, P. B. Rock, E. E. Wolfel, S. Zamudio, L. G. Moore

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which α-adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 ± 1.3 yr, 70.6 ± 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-m hypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an α-blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48% greater when subjects were α-blocked compared with their placebo trial. This difference was only 25% when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (↑ 59%) vs. blocked (↑ 35%) trial. A more dramatic effect of both altitude (↑ 104% placebo vs. 95% blocked) and blockade (↑ 50% sea level vs. 44% altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that α-adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.

Original languageEnglish
Pages (from-to)121-126
Number of pages6
JournalJournal of Applied Physiology
Volume90
Issue number1
StatePublished - 16 Jan 2001

Fingerprint

Adrenergic Agents
Catecholamines
Exercise
Oceans and Seas
Placebos
Exercise Test
Epinephrine
Norepinephrine
Follicular Phase
Prazosin
Luteal Phase
Sympathetic Nervous System
Phenylephrine

Keywords

  • Epinephrine
  • Hypoxia
  • Norepinephrine
  • Sympathetics

Cite this

Mazzeo, R. S., Carroll, J. D., Butterfield, G. E., Braun, B., Rock, P. B., Wolfel, E. E., ... Moore, L. G. (2001). Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude. Journal of Applied Physiology, 90(1), 121-126.
Mazzeo, R. S. ; Carroll, J. D. ; Butterfield, G. E. ; Braun, B. ; Rock, P. B. ; Wolfel, E. E. ; Zamudio, S. ; Moore, L. G. / Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude. In: Journal of Applied Physiology. 2001 ; Vol. 90, No. 1. pp. 121-126.
@article{5fb425ed57424dacad2f138380c8b388,
title = "Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude",
abstract = "We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which α-adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 ± 1.3 yr, 70.6 ± 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-m hypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an α-blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48{\%} greater when subjects were α-blocked compared with their placebo trial. This difference was only 25{\%} when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (↑ 59{\%}) vs. blocked (↑ 35{\%}) trial. A more dramatic effect of both altitude (↑ 104{\%} placebo vs. 95{\%} blocked) and blockade (↑ 50{\%} sea level vs. 44{\%} altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that α-adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.",
keywords = "Epinephrine, Hypoxia, Norepinephrine, Sympathetics",
author = "Mazzeo, {R. S.} and Carroll, {J. D.} and Butterfield, {G. E.} and B. Braun and Rock, {P. B.} and Wolfel, {E. E.} and S. Zamudio and Moore, {L. G.}",
year = "2001",
month = "1",
day = "16",
language = "English",
volume = "90",
pages = "121--126",
journal = "Journal of Applied Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "1",

}

Mazzeo, RS, Carroll, JD, Butterfield, GE, Braun, B, Rock, PB, Wolfel, EE, Zamudio, S & Moore, LG 2001, 'Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude', Journal of Applied Physiology, vol. 90, no. 1, pp. 121-126.

Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude. / Mazzeo, R. S.; Carroll, J. D.; Butterfield, G. E.; Braun, B.; Rock, P. B.; Wolfel, E. E.; Zamudio, S.; Moore, L. G.

In: Journal of Applied Physiology, Vol. 90, No. 1, 16.01.2001, p. 121-126.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude

AU - Mazzeo, R. S.

AU - Carroll, J. D.

AU - Butterfield, G. E.

AU - Braun, B.

AU - Rock, P. B.

AU - Wolfel, E. E.

AU - Zamudio, S.

AU - Moore, L. G.

PY - 2001/1/16

Y1 - 2001/1/16

N2 - We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which α-adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 ± 1.3 yr, 70.6 ± 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-m hypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an α-blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48% greater when subjects were α-blocked compared with their placebo trial. This difference was only 25% when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (↑ 59%) vs. blocked (↑ 35%) trial. A more dramatic effect of both altitude (↑ 104% placebo vs. 95% blocked) and blockade (↑ 50% sea level vs. 44% altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that α-adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.

AB - We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which α-adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 ± 1.3 yr, 70.6 ± 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-m hypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an α-blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48% greater when subjects were α-blocked compared with their placebo trial. This difference was only 25% when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (↑ 59%) vs. blocked (↑ 35%) trial. A more dramatic effect of both altitude (↑ 104% placebo vs. 95% blocked) and blockade (↑ 50% sea level vs. 44% altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that α-adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.

KW - Epinephrine

KW - Hypoxia

KW - Norepinephrine

KW - Sympathetics

UR - http://www.scopus.com/inward/record.url?scp=0035164124&partnerID=8YFLogxK

M3 - Article

C2 - 11133901

AN - SCOPUS:0035164124

VL - 90

SP - 121

EP - 126

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 1

ER -

Mazzeo RS, Carroll JD, Butterfield GE, Braun B, Rock PB, Wolfel EE et al. Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude. Journal of Applied Physiology. 2001 Jan 16;90(1):121-126.