Fluid-regulating hormones and plasma volume during 60 days of head-down bed rest with exercise during artificial gravity (BRACE)

Journal of Applied Physiology 2026

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Authors: Carol G. Bryans, Carmelo J. Mastrandrea, Eric T. Hedge, Christoph Siebenmann, Alan R. Hargens, Lars L. Karlsson, Richard L. Hughson, Dag Linnarsson
DOI: 10.1152/japplphysiol.00933.2025
Cited by: 0
References: 48

Abstract

Artificial gravity (AG) combined with exercise was proposed to protect plasma volume during head-down bed rest (HDBR). Our results suggest that by performing exercise with simultaneous AG, the previously identified beneficial effect of gravity-like exposure after exercise during prolonged HDBR is lost. The lack of benefit of simultaneous exercise and AG on plasma volume and fluid-regulating hormones is likely attributable to activation of the muscle pump, attenuating fluid shifts during AG countermeasure sessions.

Fields of Study & Subjects

Spaceflight effects on biology Cardiovascular Syncope and Autonomic Disorders Cardiovascular and exercise physiology

Publication details

Journal / source
Journal of Applied Physiology
Volume
140
Issue
3
Pages
621–629
Publication date
30 January 2026
Language
EN