Evaluation of the cerebral hemodynamic response to rhythmic handgrip

Cole A. Giller, Angela M. Giller, Christopher R. Cooper, Mustapha R. Hatab

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The response of the cerebral circulation to exercise has been studied with transcranial Doppler ultrasound (TCD) because this modality provides continuous measurements of blood velocity and is well suited for the exercise environment. The use of TCD as an index of cerebral blood flow, however, requires the assumption that the diameter of the insonated vessel is constant. Here, we examine this assumption for rhythmic handgrip using a spectral index designed to measure trends in vessel flow. Nineteen normal subjects were studied during 5 min of volitional maximum rhythmic right handgrip at 1 Hz. TCD velocities from both middle arteries (left and right), blood pressure, and end-tidal PCO2 were recorded every 10 s. A spectral weighted sum was also calculated as a flow index (FI). Averages were computed from the last 2 min of handgrip. Relative changes in velocity, FI, and pressure were calculated. The validity of FI was tested by comparing the change in diameter derived from equations relating flow and diameter. Mean blood pressure increased 23.8 ± 17.8% (SD), and velocity increased 13.3 ± 9.8% (left) and 9.6 ± 8.3% (right). Although the mean change in FI was small [2.0 ± 18.2% (left) and 4.7 ± 29.7% (right)], the variation was high: some subjects showed a significant increase in FI and others a significant decrease. Diameter estimates from two equations relating flow and luminal area were not significantly different. Decreases in FI were associated with estimated diameter decreases of 10%. Our data suggest that the cerebral blood flow (CBF) response to rhythmic handgrip is heterogeneous and that middle cerebral artery flow can decrease in some subjects, in agreement with prior studies using the Kety-Schmidt technique. We speculate that the velocity increase is due to sympathetically mediated vasoconstriction rather than a ubiquitous flow increase. Our data suggest that the use of ordinary TCD velocities to interpret the CBF response during exercise may be invalid.

Original languageEnglish (US)
Pages (from-to)2205-2213
Number of pages9
JournalJournal of Applied Physiology
Volume88
Issue number6
StatePublished - Jul 25 2000
Externally publishedYes

Fingerprint

Cerebrovascular Circulation
Doppler Ultrasonography
Hemodynamics
Blood Pressure
Middle Cerebral Artery
Vasoconstriction
Arteries
Pressure

Keywords

  • Cerebral blood flow
  • Exercise
  • Transcranial Doppler

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Giller, C. A., Giller, A. M., Cooper, C. R., & Hatab, M. R. (2000). Evaluation of the cerebral hemodynamic response to rhythmic handgrip. Journal of Applied Physiology, 88(6), 2205-2213.

Evaluation of the cerebral hemodynamic response to rhythmic handgrip. / Giller, Cole A.; Giller, Angela M.; Cooper, Christopher R.; Hatab, Mustapha R.

In: Journal of Applied Physiology, Vol. 88, No. 6, 25.07.2000, p. 2205-2213.

Research output: Contribution to journalArticle

Giller, CA, Giller, AM, Cooper, CR & Hatab, MR 2000, 'Evaluation of the cerebral hemodynamic response to rhythmic handgrip', Journal of Applied Physiology, vol. 88, no. 6, pp. 2205-2213.
Giller CA, Giller AM, Cooper CR, Hatab MR. Evaluation of the cerebral hemodynamic response to rhythmic handgrip. Journal of Applied Physiology. 2000 Jul 25;88(6):2205-2213.
Giller, Cole A. ; Giller, Angela M. ; Cooper, Christopher R. ; Hatab, Mustapha R. / Evaluation of the cerebral hemodynamic response to rhythmic handgrip. In: Journal of Applied Physiology. 2000 ; Vol. 88, No. 6. pp. 2205-2213.
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