Dynamic cerebral autoregulation is acutely impaired during maximal apnoea in trained divers.

Abstract

AimsTo examine whether dynamic cerebral autoregulation is acutely impaired during maximal voluntary apnoea in trained divers.MethodsMean arterial pressure (MAP), cerebral blood flow-velocity (CBFV) and end-tidal partial pressures of O2 and CO2 (PETO2 and PETCO2) were measured in eleven trained, male apnoea divers (28 ± 2 yr; 182 ± 2 cm, 76 ± 7 kg) during maximal "dry" breath holding. Dynamic cerebral autoregulation was assessed by determining the strength of phase synchronisation between MAP and CBFV during maximal apnoea.ResultsThe strength of phase synchronisation between MAP and CBFV increased from rest until the end of maximal voluntary apnoea (PConclusionsThis study is the first to report that dynamic cerebral autoregulation is acutely impaired in trained divers performing maximal voluntary apnoea. Furthermore, our data suggest that the impaired autoregulatory response is related to the change in PETCO2, but not PETO2, during maximal apnoea in trained divers.