
  Is it possible to kill yourself by holding your breath?


This question is obviously copied from Quora, but I had heard it as a fact that we cannot kill ourselves by holding our breath and I'm looking for a referenced answer.

Short answer
Healthy people cannot hold their breaths until unconsciousness sets in, let alone commit suicide.

Background
According to Parkes (2005), a normal person cannot even hold their breath to unconsciousness, let alone death. Parkes says:


  Breath‐holding is a voluntary act, but normal subjects appear unable
  to breath‐hold to unconsciousness. A powerful involuntary mechanism
  normally overrides voluntary breath‐holding and causes the breath that
  defines the breakpoint.


Parkes explains that voluntary breath‐holding does not stop the central respiratory rhythm. Instead, breath holding merely suppresses its expression by voluntarily holding the chest at a certain volume. At the time of writing, no simple explanation for the break point existed. It is known to be caused by partial pressures of blood gases activating the carotid arterial chemoreceptors. They are peripheral sensory neurons that detect changes in chemical concentrations, including low oxygen (hypoxia) and high carbon dioxide (hypercapnia). Both hypoxia and hypercapnia are signs of breath holding and both are detected by the chemoreceptors. These receptors send nerve signals to the vasomotor center of the medulla which eventually overrides the conscious breath holding.

The breaking point can be postponed by large lung inflations, hyperoxia and hypocapnia, and it is shortened by increased metabolic rates.

Reference
- Parkes, Exp Physiol (2006); 91(1): 1-15
