TY - JOUR
T1 - Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans
AU - Ogoh, Shigehiko
AU - Fadel, Paul J.
AU - Zhang, Rong
AU - Selmer, Christian
AU - Jans, Øivind
AU - Secher, Niels H.
AU - Raven, Peter B.
PY - 2005/4
Y1 - 2005/4
N2 - Exercise challenges cerebral autoregulation (CA) by a large increase in pulse pressure (PP) that may make systolic pressure exceed what is normally considered the upper range of CA. This study examined the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) and systolic (Vs), diastolic (Vd). and mean (Vm) middle cerebral artery (MCA) blood flow velocity during mild, moderate, and heavy cycling exercise. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated using transfer function analysis. PP increased by 37% and 57% during moderate and heavy exercise, respectively (P < 0.05), and the pulsatility of MCA V increased markedly. Thus exercise increased MCA Vm, and Vs (P < 0.05) but tended to decrease MCA Vd (P = 0.06). However, the normalized low-frequency transfer function gain between MAP and MCA V m and between SBP and MCA Vs remained unchanged from rest to exercise, whereas that between DBP and MCA Vd increased from rest to heavy exercise (P < 0.05). These findings suggest that during exercise, CA is challenged by a rapid decrease rather than by a rapid increase in blood pressure. However, dynamic CA remains able to modulate blood flow around the exercise-induced increase in MCA Vm, even during high-intensity exercise.
AB - Exercise challenges cerebral autoregulation (CA) by a large increase in pulse pressure (PP) that may make systolic pressure exceed what is normally considered the upper range of CA. This study examined the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) and systolic (Vs), diastolic (Vd). and mean (Vm) middle cerebral artery (MCA) blood flow velocity during mild, moderate, and heavy cycling exercise. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated using transfer function analysis. PP increased by 37% and 57% during moderate and heavy exercise, respectively (P < 0.05), and the pulsatility of MCA V increased markedly. Thus exercise increased MCA Vm, and Vs (P < 0.05) but tended to decrease MCA Vd (P = 0.06). However, the normalized low-frequency transfer function gain between MAP and MCA V m and between SBP and MCA Vs remained unchanged from rest to exercise, whereas that between DBP and MCA Vd increased from rest to heavy exercise (P < 0.05). These findings suggest that during exercise, CA is challenged by a rapid decrease rather than by a rapid increase in blood pressure. However, dynamic CA remains able to modulate blood flow around the exercise-induced increase in MCA Vm, even during high-intensity exercise.
KW - Cerebral circulation
KW - Diastolic velocity
KW - Systolic velocity
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U2 - 10.1152/ajpheart.00979.2004
DO - 10.1152/ajpheart.00979.2004
M3 - Article
C2 - 15591094
AN - SCOPUS:15744406067
SN - 0363-6135
VL - 288
SP - H1526-H1531
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 4 57-4
ER -