Em média, os seres humanos respiram automaticamente 12 vezes por minuto e esse ciclo, em conjunto com os batimentos cardíacos, é um dos dois ritmos biológicos vitais. O cérebro ajusta a cadência da respiração às necessidades do corpo sem nenhum esforço consciente. Mas o ser humano tem a capacidade de deliberadamente prender a respiração por curtos períodos. Essa capacidade é valiosa quando se precisa evitar que água ou poeira invadam os pulmões, estabilizar o tórax antes do esforço muscular e aumentar o fôlego quando necessário para se falar sem pausas.
Muito antes que a falta de oxigênio ou excesso de dióxido de carbono possa danificar o cérebro, algum mecanismo, aparentemente, leva ao ponto de ruptura, além do qual se precisa desesperadamente de ar.
Uma explicação lógica hipotética para o ponto de ruptura é que sensores especiais do corpo analisam alterações fisiológicas associadas ao inspirar e expirar antes que o cérebro apague.
O ponto de ruptura é o momento exato em que uma pessoa em apneia precisa desesperadamente de ar. O treinamento da apneia pode ampliá-la, assim como a meditação, que inunda o corpo com oxigênio, eliminando o dióxido de carbono, CO2.
(PARKES. 2013. p. 22-27).
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)
A habilidade da hemoglobina presente no sangue para captar ou liberar oxigênio, O2(g) depende da sua pressão parcial
no ambiente. O gráfico representa a variação dessa pressão parcial sanguíneo em relação ao grau de saturação de oxigênio ligado à hemoglobina.
Com base nessas informações, é correto afirmar: