title: Dynamic cerebral autoregulation changes during sub-maximal handgrip maneuver.
abstract: OBJECTIVE
  We investigated the effect of handgrip (HG) maneuver on time-varying estimates of dynamic cerebral autoregulation (CA) using the autoregressive moving average technique.
  
  
  METHODS
  Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO₂ pressure (PETCO₂), and noninvasive arterial blood pressure (ABP) were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP), resistance area-product (RAP), and time-varying autoregulation index (ARI) were obtained.
  
  
  RESULTS
  PETCO₂ did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005), which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms.
  
  
  CONCLUSIONS
  Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism.
authors: Department of Neurology, Hospital das Clinicas, University of São Paulo School of Medicine, São Paulo, Brazil.
authors: Ricardo C
authors: RC
authors: Nogueira
authors: Edson
authors: E
authors: Bor-Seng-Shu
authors: Marcelo R
authors: MR
authors: Santos
authors: Carlos E
authors: CE
authors: Negrão
authors: Manoel J
authors: MJ
authors: Teixeira
authors: Ronney B
authors: RB
authors: Panerai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000502:physiology*; D005260:Female; D006225:Hand / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D055815:Young Adult
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