CHILDREN AND DIVING
DAN medical information specialists and researchers answer your dive medicine questions
Q: My 13-year-old son recently completed his Junior Open Water Diver certification, which provided training to a maximum depth of 18 metres (60 feet). I understand there are physiological differences between a child and an adult, but what is the rationale for the depth limits?
A: Opinions vary among dive medicine experts about how to mitigate the complex issues around children and diving, such as age requirements, training levels and limitations. Children are still developing both physically and mentally, which affects the decision about whether a young diver is fully capable or requires some modification. Some training agencies allow in-water experiences for children as young as eight years old and certification by age 10.
Concerns about decompression sickness (DCS), out-of-air emergencies and gas toxicities that occur at greater depths affect depth-limitation guidelines, which vary among the training agencies. Along with DCS is the theoretical concern that bubbles from a dive could occur in and injure an epiphysis (the rounded end of a long bone). In children up to age 18, bones continue to grow from the physis (growth plate), which in long bones (arms and legs) is near each end. This area, which is quite vulnerable and consists mostly of cartilage, depends on the diffusion of vital substances to and from adjacent tissues that have a blood supply.
An injury to this area could result in abnormal bone growth.
The main causes of injuries to this region are from activities such as skiing, rollerblading, ice skating and football. Fortunately, no evidence exists of this growth-inhibition injury in young scuba divers, which may be the result of the safety measures imposed along with strict compliance by parents, guardians and dive operators. Decompression stress exists in most dives and at any age.
Other concerns about children and diving involve their maturity level, ability to handle the weight of the gear, higher risk of barotrauma, susceptibility to dehydration, vulnerability to hypothermia, ability to do a selfanalysis and willingness to accept risk. While a child’s maturity can be difficult to assess, questions such as whether you would allow that child to drive a car on the open highway (if trained and the law allowed it) starkly addresses the issue of maturity and judgement.
Additionally, most children will not understand the significance of a subtle symptom or risky situation and may be reluctant to convey their concerns in a timely manner. Close, adult supervision is necessary.
Comprehensive studies involving children are rare and extremely difficult because of the need for approval from an ethics committee or institutional review board, which is responsible for protecting the welfare, rights and privacy of human subjects and reviewing all research involving human participants. With more children diving, however, more data are being compiled.
[Robert Soncini, NR-P, DMT]
Q: I am a scuba instructor at a resort that offers introductory scuba experiences. A student who made one dive to six metres (20 feet) for less than 20 minutes used a half tank of air and later told me that he started to feel awkward as if he were stoned. Was he experiencing nitrogen narcosis?
A: At a depth of six metres (20 feet) the partial pressure of nitrogen is not elevated to the levels that cause nitrogen narcosis, the effects of which usually appear at a depth of at least 33 metres (100 feet) but sometimes can occur in somewhat shallower water.
A variety of things – such as dive gear, underlying medical conditions, psychological conditions, or drugs and medications – could cause your student’s experience, but we need more details to provide a proper explanation. His gas consumption may indicate hyperventilation occurred during the dive.
Without further speculation, the student will need a dive medical exam, and he should discuss this incident with a dive medical physician if he wishes to pursue training. If the physician finds no psychological or medical contraindications, instructors should initially conduct his dive training slowly and with close observation to ensure no recurrence.