Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre

James F. Cox, Kari U.O. Tahvanainen, Tom A. Kuusela, Benjamin D. Levine, William H. Cooke, Tadaaki Mano, Satoshi Iwase, Mitsuru Saito, Yoshiki Sugiyama, Andrew C. Ertl, Italo Biaggioni, André Diedrich, Rose Marie Robertson, Julie H. Zuckerman, Lynda D. Lane, Chester A. Ray, Ronald J. White, James Anthony Pawelczyk, Jay C. Buckey, Friedhelm J. BaischC. Gunnar Bomqvist, David Robertson, Dwain L. Eckberg

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

When astronauts return to Earth and stand, their heart rates may speed inordinately, their blood pressures may fall, and some may experience frank syncope. We studied brief autonomic and haemodynamic transients provoked by graded Valsalva manoeuvres in astronauts on Earth and in space, and tested the hypothesis that exposure to microgravity impairs sympathetic as well as vagal baroreflex responses. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, respiration and peroneal nerve muscle sympathetic activity in four healthy male astronauts (aged 38-44 years) before, during and after the 16 day Neurolab space shuttle mission. Astronauts performed two 15 s Valsalva manoeuvres at each pressure, 15 and 30 mmHg, in random order. Although no astronaut experienced presyncope after the mission, microgravity provoked major changes. For example, the average systolic pressure reduction during 30 mmHg straining was 27 mmHg pre-flight and 49 mmHg in flight. Increases in muscle sympathetic nerve activity during straining were also much greater in space than on Earth. For example, mean normalized sympathetic activity increased 445% during 30 mmHg straining on earth and 792% in space. However, sympathetic baroreflex gain, taken as the integrated sympathetic response divided by the maximum diastolic pressure reduction during straining, was the same in space and on Earth. In contrast, vagal baroreflex gain, particularly during arterial pressure reductions, was diminished in space. This and earlier research suggest that exposure of healthy humans to microgravity augments arterial pressure and sympathetic responses to Valsalva straining and differentially reduces vagal, but not sympathetic baroreflex gain.

Original languageEnglish (US)
Pages (from-to)309-320
Number of pages12
JournalJournal of Physiology
Volume538
Issue number1
DOIs
StatePublished - Jan 1 2002

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Astronauts
Valsalva Maneuver
Weightlessness
Baroreflex
Arterial Pressure
Syncope
Blood Pressure
Muscles
Peroneal Nerve
Fingers
Electrocardiography
Respiration
Heart Rate
Hemodynamics
Pressure
Research

All Science Journal Classification (ASJC) codes

  • Physiology

Cite this

Cox, J. F., Tahvanainen, K. U. O., Kuusela, T. A., Levine, B. D., Cooke, W. H., Mano, T., ... Eckberg, D. L. (2002). Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre. Journal of Physiology, 538(1), 309-320. https://doi.org/10.1113/jphysiol.2001.012574
Cox, James F. ; Tahvanainen, Kari U.O. ; Kuusela, Tom A. ; Levine, Benjamin D. ; Cooke, William H. ; Mano, Tadaaki ; Iwase, Satoshi ; Saito, Mitsuru ; Sugiyama, Yoshiki ; Ertl, Andrew C. ; Biaggioni, Italo ; Diedrich, André ; Robertson, Rose Marie ; Zuckerman, Julie H. ; Lane, Lynda D. ; Ray, Chester A. ; White, Ronald J. ; Pawelczyk, James Anthony ; Buckey, Jay C. ; Baisch, Friedhelm J. ; Bomqvist, C. Gunnar ; Robertson, David ; Eckberg, Dwain L. / Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre. In: Journal of Physiology. 2002 ; Vol. 538, No. 1. pp. 309-320.
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Cox, JF, Tahvanainen, KUO, Kuusela, TA, Levine, BD, Cooke, WH, Mano, T, Iwase, S, Saito, M, Sugiyama, Y, Ertl, AC, Biaggioni, I, Diedrich, A, Robertson, RM, Zuckerman, JH, Lane, LD, Ray, CA, White, RJ, Pawelczyk, JA, Buckey, JC, Baisch, FJ, Bomqvist, CG, Robertson, D & Eckberg, DL 2002, 'Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre', Journal of Physiology, vol. 538, no. 1, pp. 309-320. https://doi.org/10.1113/jphysiol.2001.012574

Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre. / Cox, James F.; Tahvanainen, Kari U.O.; Kuusela, Tom A.; Levine, Benjamin D.; Cooke, William H.; Mano, Tadaaki; Iwase, Satoshi; Saito, Mitsuru; Sugiyama, Yoshiki; Ertl, Andrew C.; Biaggioni, Italo; Diedrich, André; Robertson, Rose Marie; Zuckerman, Julie H.; Lane, Lynda D.; Ray, Chester A.; White, Ronald J.; Pawelczyk, James Anthony; Buckey, Jay C.; Baisch, Friedhelm J.; Bomqvist, C. Gunnar; Robertson, David; Eckberg, Dwain L.

In: Journal of Physiology, Vol. 538, No. 1, 01.01.2002, p. 309-320.

Research output: Contribution to journalArticle

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AU - Cox, James F.

AU - Tahvanainen, Kari U.O.

AU - Kuusela, Tom A.

AU - Levine, Benjamin D.

AU - Cooke, William H.

AU - Mano, Tadaaki

AU - Iwase, Satoshi

AU - Saito, Mitsuru

AU - Sugiyama, Yoshiki

AU - Ertl, Andrew C.

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AU - Diedrich, André

AU - Robertson, Rose Marie

AU - Zuckerman, Julie H.

AU - Lane, Lynda D.

AU - Ray, Chester A.

AU - White, Ronald J.

AU - Pawelczyk, James Anthony

AU - Buckey, Jay C.

AU - Baisch, Friedhelm J.

AU - Bomqvist, C. Gunnar

AU - Robertson, David

AU - Eckberg, Dwain L.

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