Face immersion increases vagal activity as assessed by heart rate variability

Eur J Appl Physiol Occup Physiol. 1997;76(5):394-9. doi: 10.1007/s004210050267.


We examined whether the diving reflex without breath-holding (face immersion alone) increases vagal activity, as determined by heart rate variability. A group of 15 men [mean age 20 (SD 3) years, height 172 (SD 5) cm, body mass 68 (SD 9) kg] performed 12 trials at various breathing frequencies (5, 10, 15, 20, 30 breaths x min(-1) and uncontrolled breath) with or without face immersion. The R-R intervals of the ECG and gas exchange variables were recorded during the 2 min of each trial. The subjects immersed their faces in 8 10 degrees C water while breathing through a short snorkel. The subject sat in the same position either with or without face immersion. The mean R-R interval (RRmean), standard deviations (SD[RR]) and coefficient of variance (CV[RR]) of the R-R interval were calculated from the R-R intervals during 30-120 s. The face immersion significantly increased SD(RR) and CV(RR) (P < 0.05), and increased RRmean (P < 0.05) at 20 breaths x min(-1). Face immersion itself had no effect on oxygen uptake, tidal volume, end-tidal O2 and CO2 partial pressures. The diving reflex without breath-holding increased the heart rate variability, indicating that face immersion alone increases vagal activity.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Carbon Dioxide / blood
  • Face / physiology*
  • Heart Rate / physiology*
  • Humans
  • Immersion / physiopathology*
  • Male
  • Oxygen Consumption / physiology
  • Respiratory Mechanics / physiology
  • Vagus Nerve / physiology*


  • Carbon Dioxide