Key result
Stepwise dynamic exercise increased MCA peak systolic blood flow velocity only up to moderate intensity, while cerebral vascular resistance index was 24% higher at maximal exercise than at rest.
Why the study?
How do central and cerebral hemodynamics respond to a stepwise increase in dynamic exercise until failure in healthy young men?
Observational
How do central and cerebral hemodynamics respond to a stepwise increase in dynamic exercise until failure in healthy young men?
The study demonstrates cerebral hemodynamic autoregulation during maximal exercise, where cerebral blood flow velocity plateaus at moderate intensity while vascular resistance increases.
Indicates preserved cerebral autoregulation during maximal exercise in healthy young men; leaves open applicability to clinical populations.
The response of central and cerebral hemodynamics to a stepwise increase in dynamic exercise until failure was studied in healthy young men. Each subject was examined using Doppler ultrasound assessment of blood flow in the middle cerebral artery (MCA), Doppler echocardiography, and spiroergometry. Hemodynamic parameters were recorded before the study and during the last several seconds of each step of the dynamic exercise. The central hemodynamic and energy exchange parameters exhibited typical changes with increasing exercise intensity. The peak systolic blood flow velocity in the MCA increased only in response to exercise of a moderate intensity (1 W/kg body weight, 45% of the maximal oxygen uptake); the further increase in exercise intensity did not affect the blood flow velocity. The cerebral vascular resistance index at the last step of the exercise was 24% higher than at rest. The increase in the MCA resistance index during the exercise was moderately correlated with the increase in the pulse pressure and systolic blood pressure, whereas the increase in blood pressure was not related to the increase in the peak systolic blood flow velocity in the MCA in response to an exercise intensity at which the oxygen uptake was higher than 45% of its maximal value. The differences between the responses of central and cerebral hemodynamics to the stepwise increase in exercise intensity reflect the phenomenon of cerebral hemodynamic autoregulation.
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Vp et al. (2006) conducted an observational in Healthy. Stepwise dynamic exercise vs. Rest was evaluated on Central and cerebral hemodynamics including peak systolic blood flow velocity in the middle cerebral artery and cerebral vascular resistance index. Stepwise dynamic exercise increased MCA peak systolic blood flow velocity only up to moderate intensity, while cerebral vascular resistance index was 24% higher at maximal exercise than at rest.
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