Feb. 6, 2003 -- Recreational scuba divers shouldn't worry about having to give up their hobby just because they're getting older, according to researchers. A new study shows the gradual decline in lung function that comes with age isn't significant enough to keep healthy elderly divers out of the water.
Using hyperbaric chambers that simulate the effects of diving at a depth of 60 feet underwater, researchers found older divers did not differ significantly from younger divers in how their lungs responded to the changes in water pressure. They were also able to maintain a healthy balance of oxygen and carbon dioxide.
"One of the key questions was whether older divers retain carbon dioxide at high levels while diving," says researcher Heather Frederick, MD, an anesthesiology resident at Duke University Medical Center, in a news release. "We found that even at a depth of 60 feet with moderate exercise, healthy older people experience increased levels of retained carbon dioxide that was statistically significant from at the surface, but clinically insignificant compared to younger subjects."
Researchers say carbon dioxide retention is a major safety issue for divers, especially during heavy exertion and with breathing problems stemming from the regulator (an underwater breathing device used in diving) or lung disease. Retaining too much carbon dioxide can lead to mental confusion, seizures, and, in extreme cases, loss of consciousness while diving.
In the study, researchers compared the responses of a group of 10 healthy adults ranging in age from 19 to 39 to those of another group of 10 healthy older adults aged 58 to 74. None of divers had a history of lung or heart disease.
Researchers measured how the divers' lungs performed at rest and at two levels of exercise at both normal pressure levels and at those experienced during dives of 60 feet underwater. The study found that even while exercising, the lungs of the older group performed at a level similar to that of the younger group.
Their findings appear in the February issue of the Journal of Applied Physiology.
"The bottom line is that healthy older divers should be able to continue diving safely," says Frederick. "Because this is the largest such study of its kind, and the fact that with the hyperbaric chamber we were able to have rigorous control over multiple physiological variables, the results of this study should help older divers feel confident about diving."
But researchers stress that their study only examined the effects of carbon dioxide retention in divers and did not look at the issue of decompression sickness or "the bends," which is a potentially dangerous condition that occurs when a diver comes to the surface too quickly or doesn't follow other standard safety precautions regarding the diving depth, length, or frequency.
When these precautions aren't followed, nitrogen bubbles may become trapped in the bloodstream due to abrupt changes in water pressure and cause numbness, tingling, joint pain, and possibly paralysis or death.
SOURCE: Journal of Applied Physiology, February 2003 • News release, Duke University Medical Center.