title: Cerebral autoregulation is temporarily disturbed in the early recovery phase after dynamic resistance exercise.
abstract: OBJECTIVE
  To determine cerebral blood-flow velocity (CBFV) and parameters of dynamic cerebral autoregulation (CA) during and after exhausting resistance exercise.
  
  
  METHODS
  Strength endurance (23 repetitions) and maximal strength training (8 repetitions) in 16 female and 16 male athletes on a leg curler (m. quadriceps training; approx. 2 s contraction) in the upright position. Registration of ECG, blood pressure by Finapres, CBFV by transcranial Doppler (TCD), and breathing by a Zak breathing-belt. Additional repetitive ergospirometry (O2-uptake, CO2-elimination, ventilation) and blood gas analyses were performed in a subgroup of seven athletes. From BP and CBFV cerebrovascular resistance (CVR), pulsatility index (PI) as well as LF-power, gain and phase-angle (frequency analysis) were derived.
  
  
  RESULTS
  All athletes showed significant (p<0.01) 15 % to 30 % increases in CBFV during both training sets without signs of flow depression due to Valsalva maneuvers. In the early recovery, when blood pressure rapidly decreased, CBFV amplitude significantly (p<0.01) increased for 60-80 seconds with mean flow (Vm) at the exercise level, while CVR and PI showed conflicting results, similar to a presyncopal reaction. Ergospirometry and blood gas analyses revealed no evidence of major changes in pCO2, but phase angle was reduced (p<0.001) after exercise, together with an LF power increase (p<0.001).
  
  
  CONCLUSIONS
  An unexpected increase in CBFV amplitude and in Vm occurs directly after dynamic resistance exercise without increased pCO2, which is comparable to a maximum leg press with hypercapnia. CVR and PI results as well as data from frequency analysis show similarities to presyncopal reactions, on the one hand, and point towards a temporarily disturbed cerebral autoregulation, on the other.
authors.affiliation: Dept. III, German Naval Medical Institute, Kopperpahler Allee 120, 24119, Kiel-Kronshagen, Germany. koch@email.uni-kiel.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Koch
authors.forename: M
authors.initials: M
authors.lastname: Ivers
authors.forename: A
authors.initials: A
authors.lastname: Gehrt
authors.forename: P
authors.initials: P
authors.lastname: Schnoor
authors.forename: A
authors.initials: A
authors.lastname: Rump
authors.forename: H
authors.initials: H
authors.lastname: Rieckert
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012129:Respiratory Function Tests; D012146:Rest / Q000502:physiology; D013147:Spirometry; D014655:Vascular Resistance / Q000502:physiology; D014891:Weight Lifting / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide