Human divers have to use portable oxygen tanks when diving for any length of time. But the increased density pressures of diving and other environmental factors can take their toll on a diver's body that may have an impact on breathing, even with oxygen tanks. That's one of the reason divers are required to receive training and certification that includes the proper use of equipment and breathing techniques.
Identification
At sea level, the air pressure is classified as one atmosphere, and for every 10 meters you dive below sea level, pressure increases an additional atmosphere. Because oxygen under such intense pressures can be toxic to humans, the gas divers use in their tanks is a compressed mixture of air that includes approximately 79 percent nitrogen and 21 percent oxygen, as well as trace amounts of other gases.
Basic Effects
Breathing through scuba equipment increases the resistance of your breathing, which can create an increased strain on your respiratory system. One of the results of this change may be hypoventilation that occurs when a reduced amount of air enters the alveoli in your lungs. The increased gas density as you dive can also lead to shortness of breath, or dyspnea.
Barotrauma
Barotrauma is a tissue injury caused by a change in pressure that can affect various parts of the body, including the lungs, and lead to breathing problems or chest pain. Because you're breathing compressed air, each breath you take at depth has more molecules than a breath taken at the surface. If you fill your lungs with compressed air at depths around 30 feet and ascend without freely exhaling, the volume of air doubles, causing your lungs to overinflate and rupture small air sacs.
Fluid in Lungs
Some divers may experience immersion pulmonary edema, a sudden development of fluid in your lungs that usually occurs early during a dive and while you're at depth. This can be caused by a malfunction of the regulator that controls gas flow and results in a cough with frothy phlegm.
Gas Toxicity
If you use an inappropriate concentration of oxygen during a deep dive, you may experience gas toxicity, which not only causes breathing problems, it can lead to vertigo, nausea, vomiting, restricted vision and fainting. Inappropriate concentrations of nitrogen can also be serious, with symptoms similar to alcohol intoxication. Another potential problem is a buildup of carbon dioxide or carbon monoxide due to faulty equipment or overexertion, both of which can make it difficult to breathe and lead to more serious side effects.
Long-Term Effects
It's long been known that prolonged and frequent diving can have a negative impact upon the lungs. A study published in the journal "Chest" in July 2005 evaluated 171 frequent divers who had unusually large lung volumes suggestive of obstructive airways disease but were otherwise young and healthy. The researchers tried to determine whether their conditions were the effect of training or natural selection, concluding that prolonged diving experience may indeed result in the development of small airways disease.
References
- Curtin University School of Physiotherapy: Scuba Diving - Physiology and Common Medical Conditions
- Merck Manual: Diving and Compressed Air Injuries; Gas Toxicity
- Merck Manual: Diving and Compressed Air Injuries; Immersion Pulmonary Edema
- Merck Manual: Diving and Compressed Air Injuries; Barotrauma
- "Chest": Large Lungs in Divers--Natural Selection or a Training Effect?; Yochai Adir; July 2005
