Why Scuba Divers Need to Exhale When Ascending: Protecting Against Decompression Sickness

When descending into the depths of the ocean, scuba divers must be aware of the risks associated with pressure changes. One crucial aspect of safe diving involves exhaling air during ascent. This behavior is essential to prevent a condition known as decompression sickness. In this article, we will explore the reasons behind this practice and its significance for scuba divers.

Understanding Pressure Changes

Breathing Under Pressure:

When divers are underwater, the pressure is significantly greater than at the surface. This increased pressure causes more nitrogen from the air in their tanks to dissolve into the body’s tissues. As a result, divers must be cautious about the gases they breathe, as a rapid ascent can lead to dangerous conditions.

The Danger of Holding Your Breath

Ascent and Decrease in Pressure:

As divers ascend, the pressure decreases. If a diver holds their breath while ascending, the air in their lungs expands due to the reduced pressure. This expansion can cause the lungs to overinflate, which may lead to serious injuries or even death.

Safe Exhalation and Controlled Ascent

Releasing Air:

By exhaling during ascent, divers allow the expanding air to escape safely. This practice helps to equalize the pressure in the lungs with the surrounding water pressure, preventing lung over-expansion injuries.

Controlled Ascent:

Exhaling while ascending also encourages a slow and controlled ascent, which is crucial for allowing excess nitrogen to safely leave the body without forming harmful bubbles. Proper ascent rates are essential for diver safety and prevent decompression sickness.

Decompression Stops: Managing Nitrogen Release

Avoiding Decompression Sickness:

Divers often make planned stops at certain depths during ascent, known as decompression stops, to allow nitrogen to safely leave the tissues. By exhaling, divers manage this process effectively, reducing the risk of decompression sickness.

Importance of Controlled Breathe During Ascent

Safe for the Diver:

When ascending, the ambient pressure drops, causing the air in the lungs to expand. If a diver does not exhale, the air will expand and potentially rupture the lungs. This is why it is crucial for divers to use their regulators and exhale during ascent.

Preventing Floating:

Additionally, when ascending, divers need to release carbon dioxide (CO2) to maintain their buoyancy. If the lungs are filled with CO2 and the diver does not breathe out, they will become too buoyant and may float up, getting trapped under the water's surface. Using the regulator ensures safe ascent and avoids such risks.

By following these safety protocols and understanding the importance of exhaling during ascent, scuba divers can enjoy their underwater adventures with peace of mind, knowing they are taking all necessary precautions to prevent decompression sickness and other related risks.