Question

Объясните почему человек надолго не может сдержать дыхание и даже в критической ситуации например находясь под водой все равно сделает вдох

Answer 1

Ныряльщик, погружаясь под воду, искусственно задерживает дыхание, волевым усилием, тормозя инстинктивное желание сделать вдох. При этом концентрация CO2 в крови повышается, что стимулирует химрецепторы, возбуждает дыхательный центр и вызывает нестерпимое желание сделать вдох

Answer 2

Why can't a person hold their breath for a long time, even in a critical situation like being underwater?

When a person holds their breath, they are consciously preventing air from entering or leaving their lungs. However, the body has a natural reflex called the "breath-holding reflex" that eventually overrides the conscious effort to hold the breath. This reflex is triggered by an increase in carbon dioxide levels in the blood and a decrease in oxygen levels. The body interprets these changes as a signal that it needs to breathe in order to replenish oxygen and remove carbon dioxide.

In a critical situation like being underwater, the body's need for oxygen becomes even more urgent. As the person continues to hold their breath, the oxygen levels in their blood gradually decrease, while the carbon dioxide levels increase. This triggers the breath-holding reflex, which causes the person to involuntarily take a breath, even if they are underwater.

The breath-holding reflex is a protective mechanism that ensures the body receives the necessary oxygen and prevents oxygen deprivation, which can lead to unconsciousness and potentially drowning.

It's important to note that the duration for which a person can hold their breath varies from individual to individual and can be influenced by factors such as physical fitness, lung capacity, and training. Some individuals, such as free divers, can hold their breath for extended periods of time due to specialized training and physiological adaptations.

In summary, the body's natural reflexes, specifically the breath-holding reflex triggered by changes in carbon dioxide and oxygen levels, prevent a person from holding their breath for an extended period of time, even in critical situations like being underwater.