European Journal of Applied Physiology

, Volume 85, Issue 5, pp 420–426

Enhanced flow-dependent vasodilatation after bed rest, a possible mechanism for orthostatic intolerance in humans

Authors

  • Philippe Bonnin
    • Hôpital Lariboisière, Explorations fonctionnelles multidisciplinaires, Institut National de la Santé et de la Recherche Médicale U541, 2 rue Ambroise Paré, 75475 Paris CEDEX 10, France
  • Ahmed Ben Driss
    • Hôpital Lariboisière, Explorations fonctionnelles multidisciplinaires, Institut National de la Santé et de la Recherche Médicale U541, 2 rue Ambroise Paré, 75475 Paris CEDEX 10, France
  • Joelle Benessiano
    • Hôpital Lariboisière, Explorations fonctionnelles multidisciplinaires, Institut National de la Santé et de la Recherche Médicale U541, 2 rue Ambroise Paré, 75475 Paris CEDEX 10, France
  • Anne Pavy le Traon
    • Clinique Spatiale – Médecine-Espace, Institut de Médecine et de Physiologie Spatiale, Hôpital Rangueil, l av. Jean Poulhès, 31403 Toulouse CEDEX 4, France
  • Alain Maillet
    • Clinique Spatiale – Médecine-Espace, Institut de Médecine et de Physiologie Spatiale, Hôpital Rangueil, l av. Jean Poulhès, 31403 Toulouse CEDEX 4, France
  • Bernard I. Levy
    • Hôpital Lariboisière, Explorations fonctionnelles multidisciplinaires, Institut National de la Santé et de la Recherche Médicale U541, 2 rue Ambroise Paré, 75475 Paris CEDEX 10, France
Original Article

DOI: 10.1007/s004210100483

Cite this article as:
Bonnin, P., Ben Driss, A., Benessiano, J. et al. Eur J Appl Physiol (2001) 85: 420. doi:10.1007/s004210100483

Abstract.

We investigated the alteration in flow-dependent-dilatation in the orthostatic intolerance occurring after bed-rest deconditioning. Eight men [aged mean (SEM) 32 (2) years] underwent two consecutive periods of 7 days of head-down-tilt (HDT, –6°) during bed rest. A control age and sex matched group [n=8, 30 (2) years], maintained its usual physical activity. Blood flow velocity (BFV) and diameter (Doppler and echotracking systems) were measured in the brachial artery, under basal conditions and during the post ischaemic hyperaemia following occlusion. The increase in BFV post-ischaemia did not change before, during and after HDT but the relative increase in the diameter was greater on the 7th day of the HDT period than before HDT [+8.8 (1.6)% compared to +3.7 (1.0)%, P<0.001]. After HDT, 11 of 16 standing tests (comprising eight subjects in the two HDT periods) had to be stopped because of orthostatic intolerance. The flow-dependent-dilatation measured at the end of HDT was negatively correlated with the post-bed-rest duration of orthostatic tolerance (r=0.78, P<0.01). After the sublingual administration of glyceryl trinitrate, there was no change in the increase in diameter. No significant changes were observed in the control group. Bed-rest deconditioning enhances the flow-dependent vasodilatation of large arteries and might contribute to the orthostatic intolerance observed following bed-rest.

Bed rest Vasodilatation Orthostatic intolerance Large arteries Endothelium

Copyright information

© Springer-Verlag 2001