What happens anatomically when we dive deep ?

Water

When diving, it is not the presence of oxygen or nitrogen that directly causes an increase in breathing rate. Rather, it is the increase in partial pressure of the gases that influences our respiratory response.

During a dive, as the diver descends deeper, the pressure exerted by the water increases. This means that the partial pressure of the gases in the breathing mixture (which typically consists of both oxygen and nitrogen) also increases. The composition of the gas mixture remains relatively constant throughout the dive, with oxygen making up around 21% and nitrogen around 79% of the air we breathe at the surface.

 

As the partial pressure of oxygen increases with depth, it can lead to a condition known as hyperoxia, which can have adverse effects on the body. To prevent these effects, such as oxygen toxicity, the use of special gas mixtures with reduced oxygen content is employed in technical diving. However, for recreational diving within standard depth limits and using air as the breathing gas, oxygen toxicity is not typically a concern.

 

The primary factor that triggers an increase in breathing rate during a dive is the build-up of carbon dioxide (CO2) in the body. When we breathe, we exhale CO2, and as we exert ourselves or engage in physical activity, our metabolic rate increases, resulting in the production of more CO2. This CO2 buildup acts as the main stimulus for our respiratory system, leading to an increase in breathing rate.

 

Nitrogen, being an inert gas, does not directly influence our breathing rate during a dive. However, it can affect the body in other ways, mainly through its tendency to dissolve into body tissues under increased pressure during a dive. The gradual accumulation of nitrogen in the body can lead to a condition called nitrogen narcosis, which can cause impairments in cognitive function, similar to alcohol intoxication. To mitigate this, divers often use gas mixtures with reduced nitrogen content, such as helium-based mixes, at greater depths.

Note: - When we dive deep, anatomically, the increased pressure causes several physiological changes in our body. These changes include compression of the lungs, increased pressure on the chest, and increased pressure on the blood vessels.

 

In summary, while the increase in partial pressure of oxygen with depth can have potential health risks, it is the buildup of carbon dioxide in the body that primarily triggers an increase in breathing rate during a dive. Nitrogen, on the other hand, does not directly affect breathing rate but can cause nitrogen narcosis at greater depths.

- Tanmay Bhati

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