@inproceedings{8680909,
  abstract     = {{Acute  breath-holding  deprives  the  human  body  from  oxygen.  In  an  effort  to  protect  the  brain,  the  diving  response  is  initiated,  coupling  several physiological responses. The aim of this study was to describe the physiological responses to voluntary breath-holding at the cardi-ac, peripheral and cerebral level in order to obtain insight into the protective mechanisms for the brain.METHODS:31 physically active subjects (17 male, 14 female, 23.3 ±1.8 years old) performed a maximal static breath-hold in a seated position. Heart rate  (HR)  and  muscle  (M.  Vastus  Lateralis)  and  cerebral  (prefrontal  cortex)  oxygenation  (by  means  of  near-infrared  spectroscopy)  were  continuously measured. RM MANOVA’s were used to identify changes in HR, cerebral (cTOI) and peripheral tissue oxygenation (mTOI) and oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin at different time points during apnea.RESULTS:Subjects held their breath for 157 ±41 s on average (range: 96-244 s). HR started decreasing 15 s after the onset of apnea (p=0.003) reach-ing minimal values after 83 ±58 s. HR dropped on average by 27 ±14 bpm (30 ±13%) from baseline (p<0.001). mTOI started decreasing 10 s after  apnea  (p<0.001)  and  continued  to  decrease  until  10  s  post  apnea,  reaching  baseline  only  30  s  post  apnea  (p=0.369).  mTOI  fell  on  average by 8.6 ±4% (p<0.001). Following an immediate drop after 5 s (p<0.01), cTOI increased continuously, reaching a maximal increase of 4.6  ±3%  (p<0.001)  after  100  ±49  s,  followed  by  a  steady  decrease  until  the  end  of  apnea.  cTOI  fell  on  average  6.5  ±7.6%  below  baseline (p<0.001)  with  individual  decreases  up  to  25%.  cTOI  increased  immediately  after  apnea,  already  reaching  baseline  10  s  post  apnea  (p=0.811).  One  subject  fainted  during  testing  after  only  65  s  of  apnea.  Visual  analysis  revealed  a  similar  pattern  for  HR.  Examination  of  mTOI,  mO2Hb  and  mHHb  suggested  impaired  peripheral  vasoconstriction,  while  cTOI  showed  a  very  strong  immediate  drop,  followed  by incomplete recovery resulting in a second fast drop in cTOI until the subject passed out.CONCLUSION:During apnea, the human body elicits several protective mechanisms in order to protect itself against the deprivation of oxygen. HR slows down  decreasing  oxygen  demand  of  the  cardiac  muscle.  The  decrease  in  mTOI  and  increase  in  cTOI  imply  a  redistribution  of  blood  flow  prioritizing the brain. However, data from one participant suggests that syncope can be induced by impaired redistribution, observed as a less pronounced peripheral vasoconstriction deducted from muscle oxygenation responses and a disturbed cerebral oxygen.}},
  author       = {{Bouten, Janne and Bourgeois, JG and Boone, Jan}},
  booktitle    = {{European College of Sport Science, 25th Annual congress, Abstracts}},
  isbn         = {{9783981841435}},
  language     = {{eng}},
  location     = {{Sevilla}},
  pages        = {{204--204}},
  title        = {{Hold your breath : peripheral and cerebral oxygenation during dry static apnea}},
  year         = {{2020}},
}