Carotid artery blood flow and middle cerebral artery blood flow
velocity during physical exercise.
Hellstr[diaeresis]om, G., W. Fischer-Colbrie, N. G. Wahlgren, T.
Jogestrand.
Department of Neurology, Karolinska Hospital, Department of
Clinical Physiology, Huddinge Hospital, Stockholm, Sweden
APStracts 3:0205A, 1996.
Factors controlling cerebral blood flow (CBF) during exercise are
complex and incompletely known. Different techniques have shown
partly contradictory results of changes in regional and global
cerebral perfusion during dynamic exercise in healthy subjects. To
elucidate the global CBF response to supine stepwise increasing
physical exercise, we measured blood flow in the left common carotid
artery (FCCA) and the left internal carotid artery (FICA)
simultaneously with the blood flow velocity in the ipsilateral middle
cerebral artery (VMCA) using duplex ultrasonography and transcranial
Doppler ultrasonography. During moderate exercise intensity (60-67%
of maximal capacity), the VMCA increased 14% (p<0.001), the FICA
17% (p<0.01), and the FCCA 33% (p<0.001), compared to
baseline values. High physical exercise intensity (80-90% of maximal
capacity) tended to reduce VMCA and FICA compared to moderate
exercise in contrast to a continued increase in FCCA. The results
indicate an increased global CBF during exercise. This increase was
reduced during hard exercise due to a decrease of the arterial PCO2
secondary to hyperventilation.
Received 24 March 1995; accepted in final form 12 February 1996.
APS Manuscript Number A320-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96