The human body has several reflex oxygen-conserving adaptations that manifest under diving conditions. The adaptations include: Reflex bradycardia: Drop in heart rate.Splenic contraction: Releasing red blood cells carrying oxygen.Blood-shift: Blood flow and volume is redistributed towards vital organs by means of a reflex vasoconstriction. Blood vessels distend and become engorged, which in the case of the pulmonary capillaries assists with pressure compensation that comes with increasing diving depth, and without which a largely air-filled chest cavity would simply collapse for lack of compliance.Body-cooling: peripheral vasoconstriction results in cooling of peripheral tissue beds, which lower their oxygen demand in a thermodynamic manner. In addition, Murat et al. (2013) recently discovered that breath-holding results in prompt and substantial brain cooling, just like in diving birds and seals. (Dry) breath-holds result in cooling on the order of about 1°C/minute, but this is likely to be greater with cold water submersion, in proportion to the magnitude and promptness of the dive response.
Posted on: Sun, 09 Mar 2014 15:21:33 +0000
Trending Topics
Recently Viewed Topics
© 2015