A diminished aortic-cardiac reflex during hypotension in aerobically fit young men

X. Shi, C. G. Crandall, J. T. Potts, J. W. Williamson, B. H. Foresman, P. B. Raven

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We compared the aortic-cardiac baroreflex sensitivity in eight average fit (AF: V̇O(2max) = 44.7 ± 1.3 ml · kg-1 · min-1) and seven high fit (HF: V̇O(2max) = 64.1 ± 1.7 ml · min-1 · kg-1) healthy young men during hypotension elicited by steady state sodium nitroprusside (SN) infusion. During SN mean arterial pressure (MAP) was similarly decreased in AF (-12.6 ± 1.0 mm Hg) and HF (-12.1 ± 1.1 mm Hg). However, the increases in heart rate (HR) were less (P < 0.023) in HF (15 ± 3 bpm) than AF (25 ± 1 bpm). When sustained neck suction (NS, -22 ± 1 torr in AF and -20 ± 1 torr in HF, P > 0.05) was applied to counteract the decreased carotid sinus transmural pressure during SN, thereby isolating the aortic baroreceptors, the increased HR remained less (P < 0.021) in HF (8 ± 2 bpm) than AF (16 ± 2 bpm). During both SN infusion and SN+NS, the calculated gains (i.e., ΔHR/ΔMAP) were significantly greater in AF (2.1 ± 0.3 and 1.3 ± 0.2 bpm · mm Hg-1) than HF (1.2 ± 0.2 and 0.6 ± 0.2 bpm · mm Hg-1). However, the estimated carotid-cardiac baroreflex sensitivity (i.e., the gain difference between the stage SN and SN+NS) was not different between AF (0.7 ± 0.2 bpm · mm Hg-1) and HF (0.6 ± 0.1 bpm · mm Hg-1). These data indicated that the aortic-cardiac baroreflex sensitivity during hypotension was significantly diminished with endurance exercise training.

Original languageEnglish (US)
Pages (from-to)1024-1030
Number of pages7
JournalMedicine and Science in Sports and Exercise
Volume25
Issue number9
StatePublished - 1993

Fingerprint

Nitroprusside
Hypotension
Reflex
Baroreflex
Heart Rate
Arterial Pressure
Furylfuramide
Carotid Sinus
Pressoreceptors
Exercise
Pressure

Keywords

  • ADAPTATION
  • BARORECEPTOR SENSITIVITY
  • EXERCISE TRAINING
  • NECK SUCTION
  • NITROPRUSSIDE

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

A diminished aortic-cardiac reflex during hypotension in aerobically fit young men. / Shi, X.; Crandall, C. G.; Potts, J. T.; Williamson, J. W.; Foresman, B. H.; Raven, P. B.

In: Medicine and Science in Sports and Exercise, Vol. 25, No. 9, 1993, p. 1024-1030.

Research output: Contribution to journalArticle

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AU - Shi, X.

AU - Crandall, C. G.

AU - Potts, J. T.

AU - Williamson, J. W.

AU - Foresman, B. H.

AU - Raven, P. B.

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N2 - We compared the aortic-cardiac baroreflex sensitivity in eight average fit (AF: V̇O(2max) = 44.7 ± 1.3 ml · kg-1 · min-1) and seven high fit (HF: V̇O(2max) = 64.1 ± 1.7 ml · min-1 · kg-1) healthy young men during hypotension elicited by steady state sodium nitroprusside (SN) infusion. During SN mean arterial pressure (MAP) was similarly decreased in AF (-12.6 ± 1.0 mm Hg) and HF (-12.1 ± 1.1 mm Hg). However, the increases in heart rate (HR) were less (P < 0.023) in HF (15 ± 3 bpm) than AF (25 ± 1 bpm). When sustained neck suction (NS, -22 ± 1 torr in AF and -20 ± 1 torr in HF, P > 0.05) was applied to counteract the decreased carotid sinus transmural pressure during SN, thereby isolating the aortic baroreceptors, the increased HR remained less (P < 0.021) in HF (8 ± 2 bpm) than AF (16 ± 2 bpm). During both SN infusion and SN+NS, the calculated gains (i.e., ΔHR/ΔMAP) were significantly greater in AF (2.1 ± 0.3 and 1.3 ± 0.2 bpm · mm Hg-1) than HF (1.2 ± 0.2 and 0.6 ± 0.2 bpm · mm Hg-1). However, the estimated carotid-cardiac baroreflex sensitivity (i.e., the gain difference between the stage SN and SN+NS) was not different between AF (0.7 ± 0.2 bpm · mm Hg-1) and HF (0.6 ± 0.1 bpm · mm Hg-1). These data indicated that the aortic-cardiac baroreflex sensitivity during hypotension was significantly diminished with endurance exercise training.

AB - We compared the aortic-cardiac baroreflex sensitivity in eight average fit (AF: V̇O(2max) = 44.7 ± 1.3 ml · kg-1 · min-1) and seven high fit (HF: V̇O(2max) = 64.1 ± 1.7 ml · min-1 · kg-1) healthy young men during hypotension elicited by steady state sodium nitroprusside (SN) infusion. During SN mean arterial pressure (MAP) was similarly decreased in AF (-12.6 ± 1.0 mm Hg) and HF (-12.1 ± 1.1 mm Hg). However, the increases in heart rate (HR) were less (P < 0.023) in HF (15 ± 3 bpm) than AF (25 ± 1 bpm). When sustained neck suction (NS, -22 ± 1 torr in AF and -20 ± 1 torr in HF, P > 0.05) was applied to counteract the decreased carotid sinus transmural pressure during SN, thereby isolating the aortic baroreceptors, the increased HR remained less (P < 0.021) in HF (8 ± 2 bpm) than AF (16 ± 2 bpm). During both SN infusion and SN+NS, the calculated gains (i.e., ΔHR/ΔMAP) were significantly greater in AF (2.1 ± 0.3 and 1.3 ± 0.2 bpm · mm Hg-1) than HF (1.2 ± 0.2 and 0.6 ± 0.2 bpm · mm Hg-1). However, the estimated carotid-cardiac baroreflex sensitivity (i.e., the gain difference between the stage SN and SN+NS) was not different between AF (0.7 ± 0.2 bpm · mm Hg-1) and HF (0.6 ± 0.1 bpm · mm Hg-1). These data indicated that the aortic-cardiac baroreflex sensitivity during hypotension was significantly diminished with endurance exercise training.

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KW - NITROPRUSSIDE

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