When is a person old enough to dive?

How old is too old?

By Samuel Shelanski, M.D.

The next time you're on a dive boat, look around. A teenager dons gear alongside his parents. Next to you, a couple in their 50s does an equipment check; she's got 15 years of experience but her buddy was certified only two months ago. The divers about to giant-stride into the water with you span a broad spectrum of age, and with that comes an equally broad spectrum of age-related considerations.

Medically, these two groups-young divers and older divers-pose some interesting questions. When is a person old enough to dive? How old is too old? As with many issues in diving, the answers are part fact, part hypothesis, and a large part common sense.

Young Turks

All of the major certifying agencies require a minimum age--usually 12--for obtaining a junior diver certification; 15 is generally the minimum age for basic certification. It is believed that diving prior to reaching full bone maturity can lead to bone defects or adversely affect growth. The epiphyseal plates near the ends of long bones are the major sites of new bone growth during development, and are very susceptible to injury or damage.

The destructive effects that diving and DCS can have upon bone are well documented in commercial divers, but have not been described in recreational divers. Despite the lack of direct evidence, Dr. Carl Edmonds, author of Diving and Subaquatic Medicine and an expert on hyperbaric medicine, recommends that children not dive below 30 feet until their epiphyseal plates have fused--during puberty--in order to minimize the risk of bony deformities. There is little hard data to support this recommendation, but it is a reasonable extrapolation of what is known. Because only x-rays can show if a child's epiphyseal plates have fused, diver wannabes should have a radiologic check-out before enrolling in a junior diver class.

More important than actual chronological age when deciding if children are ready to begin diving is their level of physical and psychological development. A child must be physically capable and emotionally mature enough to respond to the unexpected, from strong currents to an out-of-air situation.

Even then, it is strongly suggested that children who dive buddy up with a more experienced adult in the event that an unforeseen problem occurs.

Parents must be realistic in deciding when their children are ready to start diving. As divers, many of us are fanatical about our sport, and can't understand how the rest of the world survives without breathing compressed air. Make sure that little Billy wants to dive before signing him up for a class. A child may be reluctant to express fears in the face of a parent's enthusiasm, and an unwilling participant is substantially more likely to wind up in trouble while diving.

Golden Agers

Unwilling participation is far less of an issue with the older age group. Although some of these divers entered the sport when they were in their 20s and 30s, many of the older divers that you will encounter these days are relatively new to diving. While the issues of emotional maturity are essentially moot in this group of divers, age exacts a physical toll on the body that leads to physical limitations and risks that don't apply to most younger divers.

As divers age, their risk of DCS increases. This is thought to result from a decrease in blood flow to large muscle beds, so that absorbed gases wash out more slowly. It is also thought that as the cartilage in joints wears down, it gets rough and increases the likelihood of bubble nuclei forming, increasing the risk of clinical DCS. These changes start to happen early in life. Air Force data on altitude DCS show that a 28-year-old is twice as likely to get DCS as an 18-year-old.

While we have little control over our chronological age, the same cannot be said about physiological age. Divers need to stay in good physical shape. As people age, they are more likely to reduce their activity level, and general fitness declines. As a result, many health factors related to health also decline. These include strength, endurance, flexibility and cardiovascular fitness. Cardiovascular disease is of particular concern to the older diver. It is thought to be responsible for up to 20 percent of all recreational diving deaths. For this reason, cardiovascular risk factors such as smoking, hypertension, high cholesterol and obesity are of even greater concern when found in older divers. Any person who is 45 or older and wishes to dive should have an exercise stress test as part of a physical exam. Poor exercise tolerance or evidence of coronary artery disease on such a test would be grounds for excluding a person from diving.

Are these putative risks, for both older and younger divers, reflected in the data on diving accidents? The answer is not particularly clear. According to DAN's data from 1993, of the 508 diving accidents reported, only 15 (3 percent) were in divers under the age of 20, while 90 (18 percent) were in divers over 45. However, it is unclear whether these figures are simply representative of the age distribution of the diving population, or whether they are indicative of a disproportionate number of accidents in either group.

Data collected by the National Underwater Accident Data Center at the University of Rhode Island tracked more than 2,600 scuba fatalities, dating back to 1970. This data showed that the number of deaths in divers over the age of 50 increased through the 1980s, reaching 18 percent of all fatalities by 1986. These numbers coincide with an increase in certification of older divers, so it is still not clear whether these numbers indicate an increased risk of death for older divers.

This question was clarified slightly by the 1989 Australia and New Zealand study on diving deaths. This exhaustive study categorized diving deaths by contributing cause as well as age. The study found that the majority of diving deaths occurred in the 21 to 35 age group, with a second peak in the 45 and older group. Most of the deaths in this second peak were attributable to cardiac causes.

The message? While most diving deaths occur in divers between 20 and 40, it is clear that there are unique risks to those both younger and older. By making sure that divers are adequately trained, physically and emotionally fit to dive, and that they dive well within accepted limits, the number of accidents can be stabilized, or reduced, despite the rapid increase in numbers of divers.

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Posted March 1, 2003