Paula does not become ill very often, despite her slow breathing at rest. And when she did get very ill, twenty years ago, she did not die, despite her slow breathing decreasing further-from 5 to 3 breathes per minute. Breathing took all her strength. Her tidal volume must still have remained big enough, but she was not able to do much, other than breathe. She did not feel well, and was pretty ill. She did not know what was wrong and she was not aware of having trouble breathing. She did not sense her breathing rate, and I think that this is normal. No one senses their breathing rate or volume. These are orchestrated seamlessly by the brain stem in response to conditions in the body. And, it seems, if the breathing rate goes down instead or up, the brain stem uses all the other organ systems of the body to maintain acid base levels enough to stay alive until the crisis is over.
Kraepelin noted, in the last century, that his patients with very slow breathing became quiet, distressed, inactive, etc…they became very unwell, they lost weight….and few of them died. Their brain stem sometimes suddenly switched to a period of too rapid breathing, during which they became even more unwell- actively delirious [mania used to mean delirium without fever] …and did sometimes die of a sudden heart attack, but still, most did not die. Most eventually regained their mental and physical health. These mostly young adults were very healthy except for their inability to increase their breathing when significantly ill enough. Even mild retention of carbon dioxide in the blood [a kind of respiratory failure] will eventually cause a delirium [depressed, manic and mixed].
The injury to control of breathing mechanisms seems to be protective against death. And these same respiratory injuries are responsible for the stable chronic recognizable patterns of severe disabling depression [quiet agitated delirium] and mania [euphoric agitated delirium] and mixed delirium. It is all a function of the injury preventing normal intake and out-take of breath, directly complicating acid base balance by the brain stem. [Luckily the brain stem is doing its job, it is keeping the person alive to hopefully recover spontaneously or with treatment [faster] instead of dying. All three patterns of delirium often lead to death in people without this respiratory injury. The Paula’s of the world survive.
But delirium can still ruin your huge parts of your life, it is still an emergency. Emergency treatments should limit the length of the delirium letting you recover your health and your life more quickly.
Of Sound Mind 