Why Taking a Breath from a Scuba Tank While Freediving Is Extremely Dangerous
Freediving and scuba diving are two distinct underwater disciplines, each with its own set of rules and safety procedures. While many divers enjoy both activities, mixing them improperly can lead to serious, even fatal, consequences. One of the most dangerous mistakes a freediver can make is taking a breath from a scuba tank while at depth. This practice poses a severe risk of lung overexpansion injury, which can be life-threatening. Here's why you should never take a breath from a scuba tank while freediving.
The Danger of Lung Overexpansion Injuries
Scuba divers breathe compressed air at depth, which means the air inside their lungs is at a higher pressure than at the surface. As they ascend, this air expands. However, scuba divers are trained to exhale continuously while ascending, preventing dangerous pressure buildup in the lungs.
Freedivers, on the other hand, dive on a single breath of air taken at the surface. Their lungs compress as they descend due to the increase in water pressure. If a freediver were to take a breath from a scuba tank at depth, their lungs would fill with high-pressure air. As they ascend on a single breath without exhaling properly, the expanding air can rupture lung tissues, leading to a lung overexpansion injury.
Why Freedivers Ascend Too Quickly for Scuba Procedures
One of the key safety principles in scuba diving is a controlled, slow ascent to allow for proper gas exchange and to avoid decompression sickness. Freedivers, however, typically ascend much faster since they are on a single breath-hold. Even if a freediver takes only a small breath from a scuba tank, they will likely ascend at a much faster rate than a scuba diver. This rapid ascent does not allow enough time for the expanding air in the lungs to be safely expelled, increasing the risk of barotrauma.
The Risk of Decompression Sickness
Decompression sickness (DCS), also known as “the bends,” occurs when dissolved nitrogen in the body forms bubbles due to a rapid decrease in pressure. Scuba divers manage this risk by following decompression procedures and ascending slowly. Freedivers are generally not at risk of DCS because they do not breathe compressed air. However, if a freediver takes a breath from a scuba tank at depth, their body will absorb nitrogen from the pressurized air. If they then ascend rapidly, nitrogen bubbles can form in the bloodstream, leading to severe pain, neurological issues, and even death.
Emergency Situations and Exceptions
The only situation where taking a breath from a scuba tank while freediving might be acceptable is during a life-threatening emergency where a freediver is unable to reach the surface without assistance. In such cases, the freediver should share air with a trained scuba diver and ascend together at a controlled rate, following proper scuba ascent procedures. However, this is an extremely rare scenario, and it is always safer to plan dives in a way that avoids such risks entirely.
Mixing freediving and scuba diving without proper training and precautions can have catastrophic consequences. Lung overexpansion injuries are entirely preventable, but they can be fatal if proper procedures are not followed. If you engage in both scuba and freediving, always remember to keep the two activities separate. Never take a breath from a scuba tank while freediving, and always prioritize safety in all underwater activities. By respecting the unique physiology of each discipline, you can enjoy both sports safely and responsibly.