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Physiological risk factors for pre-teen divers?

Discussion in 'Diving Medicine' started by AllenG, May 3, 2002.

  1. AllenG

    AllenG Nassau Grouper

    I am wondering if any of ScubaBoard's resident diving docs can offer any insights regarding the physiological risk factors associated with pre-teen diving. I am not looking for yes/no recommendations, as the pre-teen in question (my 11 y.o. daughter) is already certified and diving. The proverbial cork is already out of the bottle and now that she's seen the underwater realm, there's no turning back! Given that she is diving, I am, however, wondering re impact of UW pressure on physiological development/growth/bone mass development. I have read lots of unsubstantiated guesses, poorly constructed research, and misinterpreted data on such matters. Perhaps some of our more informed and careful diving docs can help sort out these issues, especially as they relate to (1) multiple dives/day for a week or more, and (2) average & max depth. I do understand that, when in doubt, less frequent diving to a lesser depth reduces the putative impact, but a more factually-based position would be helpful?

    As always, your careful insights and analyses will be appreciated.
  2. jbd

    jbd Dive Shop

    I'm thinking that you have already done a search on this site about this topic. I know last year we had a discussion about it. If I recall correctly DocVikingo has written an article which I think he posted during that discussion.

    I know this is not the kind of information you are looking for but, the owner of my LDS has been diving actively since the age of 10 and has no known problems along these lines.

    Also as I recall from last year the general opinion was that there never would be definitive research on this since no one would be willing to subject kids to the depths and exposures that would yield solid conclusions one way or another.
  3. AllenG

    AllenG Nassau Grouper

    A search had turned up one posting in which, as I am recalling, DocV had identified the issue, but politely suggested that perhaps others might have more complete or thorough understanding of the issues.
  4. Liquid

    Liquid Instructor, Scuba

    I know a guy that's now over 50 years old, and have dived since he was 10 years old. He is reall fat and ugly but I dont think it has anything to do with diving ;)

    DAmn it! I have to make him some how read this page!!!!!!
    He'll lough so hard and then give me some......
  5. John Reinertson

    John Reinertson Barracuda

    As I understand it from some animal studies, there are concerns about the increased vascularity of the bone growth centers and their risk for bubbling and damage.

    There is no human research on this topic.

    In some animal studies, (if I remember the diving med courses correctly) there was a tendency to have bone injury, but I think it was done in rats, and done with dive profiles calculated to produce decompression illness.

    This doesn't clearly equate to humans diving profiles within the tables, but it is at least concerning.

    If your child is diving, I would suggest conservative profiles and longer safety stops. We don't know that that will eliminate the risk that we think is there, but there are some reasons to think it would.
    I certainly would steer a child away from any exotic or "Tek" or high risk diving for the above reasons.

    There's enough truly rotten stuff that happens in the world by accident.
    We don't need to worsen the odds against us or our children.

    Dive Safe,
  6. DocVikingo

    DocVikingo Senior Member Staff Member

    Hi AllenG,

    The following copy of my Sep '01 Undercurrent http://www.undercurrent.org/ piece "The Minds and Bodies of Children -- are they really suited to scuba?," may address some points of interest to you:

    "Make no mistake. More children at increasingly younger ages are going scuba diving. Many diving parents want their children to experience the colors, creatures, calm and curiosity of the underwa t e r world. And, the dive industry wants to expand the market. By marketing diving to families and certifying children, the entire industry — the training agencies, the manufacturers, dive stores, and dive travel — benefits economically.

    With an eye toward promoting the sport, in 1999 the Recreational Scuba Tr a i n i n g Council, a standard- setting body whose membership is composed of training agencies, eliminated its recommended age of 15 for junior certification. No longer fettered by minimum age limits, several major training agencies lowered the age for extended dive experiences and conditional certifications. For example, today PA D I ’s “Seal Team” and SSI’s “Scuba Rangers” offer scuba experiences to children as young as age 8, and junior open water certification at age 10.

    Despite the undeniable appeal of introducing youngsters to the underwater world and making scuba a family activity, several psychological and physiological reasons demand consideration in opening scuba to 8-year-olds.

    To understand the psychological and physiological concerns requires recognizing the age varation at which children make the cognitive, behavioral and physical transition from one developmental stage to the next. In fact, this well-known variability itself forms a basis for questioning the policy of lowering ages.

    Cognitive Issues:

    Among cognitive concerns is the child’s ability to acquire and manipulate information. According to Jean Piaget’s widely influential system, three developmental periods are germane to child scuba divers.

    The first, the Pre-Operational stage, begins about age 2 and extends to about age 7. In the later years, a child has an intuitive though rudimentary grasp of some logical concepts. A child’s perceptions still dominate his judgment. He will tend to focus attention on one aspect of an object while ignoring others. He is unable to understand the principles underlying proper behavior, relying on the do’s and don’t s imposed by authority. While it is uncommon, some children 8 and older are delayed in the Pre-Operational stage and the dive agencies have no explicit criteria for screening them out. But, a late-developing child could forget to continue to exhale while making an emergency ascent or may not place anothers’ safety on par with his own. It is up to the instructor (who could himself be a teenager of 18) to recognize cognitive immaturity and refuse to teach the child.

    During the next, or Concrete Operational stage (covering approximately age 7-11 years), logical thought develops. But it remains dependent upon concrete referents. While the child is developing the ability to appreciate concepts such as length, mass and volume, and to arrange objects in a logical sequence, it
    remains linked to objects present — not objects in the abstract. One can assume that the child at age 11 is much more capable than the child at age 8 in this stage.

    The new policy for PADI, SSI and others clearly allows children in the Concrete Operational stage (7-11 years) to enroll in scuba programs. The potential risks are not inconsequential. For example, a child in this period may be able to understand basic scuba theories such as Boyle’s law and solve a few problems. However, he will be unable to hypothesize from such principles and extend them to a wider application — such as appreciating that an empty tank may allow for a few more breaths as one ascends. More worrisome, when faced with a scuba emergency, such as a BC inflator mechanism stuck in the open position, they will unlikely be able to generate multiple solutions to the situation. And, they would unlikely be able to select the best alternative: attempting to vent the BC continuously rather than disconnecting the inflator hose.

    In the final stage of Formal Operations (covering approximately age 11-15 years), thought gradually becomes less tied to concrete reality and becomes more abstract. The ability to generate abstract propositions and multiple hypotheses and assess their possible outcomes becomes evident. This development allows individuals to think about what might be, rather than just what is. The levels of cognitive ability evident when a child completes this stage are those most appropriate to safe scuba.

    Behavioral Issues:

    Children are notorious for being exuberant, impulsive and feeling invincible. These are normal childhood traits that typically aren’t mastered until the mid to late teens, or even later. This has obvious implications for the appreciation and avoidance of risk — and the ability to act as a responsible dive buddy.

    Physical Issues:

    Patent foramen ovale (PFO): During fetal development, blood flows through a small opening between the right and left upper chambers of the heart. The lungs are inoperative and the mother oxygenates blood. At birth, however, this opening is supposed to close, shunting blood to the now-functioning lungs. While this “hole in the heart” usually seals by the third month of life, it does not always. Estimates of incomplete closures in older children and younger teens run higher than 50 percent in certain groups. Whatever the exact figures, the research suggests an increased incidence of PFO as age decreases below 20.

    Without complete closure, blood can flow from the right to the left side of the heart without passing through the lungs. Increases in right chamber pressure that occur with common equalization techniques like the Valsalva maneuver — squeezing your nose, closing your mouth, and blowing — can move blood through the hole and bypass the lungs. When this happens, nitrogen bubbles that can form in the bloodstream may pass directly into the arteries and not be filtered by the lungs. This of course can
    lead to an embolism or DCS.

    Possible retardation of bone growth: Long bones, like the humerus and femur, mature from growth plates, the active ends of bones where increases in length occur. The last of the growth plates generally do not cease activity until the late teens or early twenties. As these growth plates depend upon nearby blood vessels for oxygen and nutrition, physicians have long been concerned that nitrogen bubbles in the bloodstream may result in damage to these critical tissues. In addition, the development of bone and connective tissue involves molecular oxygen, raising the possible adverse effects of the elevation of oxygen partial pressures occurring during diving.

    Heat regulation: Due to a relatively large skin mass to body mass ratio, children do not regulate body heat as well as adults. Until the mid-teens or so, youth are far more vulnerable to hypothermia. And, alarmingly, a child may be hypothermic yet have no complaints, and still feel warm to the touch.

    Eustachian tube development: In younger children, the Eustachian tube is narrower and more horizontal than later in development. While this is unlikely to be problematic in children over age 12, it has implications for equalizing, including potentially damaging reverse squeeze, for children closer to age 8.

    Furthermore, young divers with immature Eustachian tubes may be subject to more frequent middle ear infections. Since a diver must be able to clear his ears safely and comfortably, a person with a middle ear infection should not dive. So, a child must recognize it, tell someone, and not dive.

    The Response of the
    Dive Training Community

    The positions of several agencies are based on conclusions expressed by John Kinsella, Director, Training and Quality Management of PADI America, in his article entitled “Kids and Diving” (The PADI Undersea Journal — First Quarter, 2001).

    After reviewing the evidence for potential medical concerns expressed by DAN, he concluded: “There is insufficient information available to make any evidence-based medical judgment for or against children in scuba diving.”

    SSI allows children as young as age 8 to have a shallow water scuba experience in their “Scuba Rangers” program. Children 10 to 12 may receive a junior open water certification with certain limitations. Once they turn 12, they may upgrade to a regular open water diver. Those 12 and older are eligible to become a Nitrox specialty diver.

    When we asked Dennis M. Pulley, SSI Director of Training , about their program, he told us that “SSI is aware of medical and psychological concerns in divers as young as 12.” However, he cited the RSTC position that medical experts are unable to provide any documentation or proof why an individual must be at least 12 years of age to begin scuba training.

    Pulley also remarked that, “Psychologically, one could argue that many young males between the ages of16 and 30 could have the same attitude of being invincible.”

    It is true that many theoretical medical and behavioral concerns have not been subjected to controlled studies on humans. And may never. The ethical issues are obvious. For those issues that may be studied, it will be a long and painstaking process, as evidenced by how difficult gathering useful data on DCS has been.

    It seems, then, to drop the training age with no longitudinal, hard data about the effect on children is questionable at best.

    Historically, the response of training agencies to incomplete knowledge has been to err on the side of safety.

    Think about how the agencies have treated dive tables for all gases, how they fought against Nitrox because it was unsafe and unstudied, how conservative they have been on dive-to-fly estimations, depth limits, and clearance to dive for medical disorders that may pose a risk to scuba divers. Yet the leadership in this conservative industry has taken a “relaxed” attitude regarding the diving safety of children.

    However, while there may be no formal studies of the effect of diving on children, PADI and European-based CMAS have long offered swimming pool scuba to children as young as age 4, and restricted open water certification for those to age 8. To date, the results cause no alarm. Even allowing for the extent to which good PR may influence disclosure of adverse events, if children were sustaining harm in significant numbers, liability issues would presumably force this information into the open.

    To their credit, PADI and SSI have taken sensible steps to address medical and developmental concerns.

    For example, the Seal Team, Bubblemaker and Scuba Rangers programs are restricted to a pool or pool-like environment. Both agencies require that certified divers ages 10-11 be accompanied by a certified parent, legal guardian, or professional dive leader, and limit maximum depth to 40 feet. We should note, however, that while these depth limits do control the partial pressures of nitrogen and oxygen, an embolism can occur in as little as four feet of water.

    PADI has taken special educational efforts to alert instructors to the safety issues. And while current instructors haven’t been trained to certify children but still can, future instructors will find extensive material incorporated into upcoming revised Instructor Development Courses.

    Nonetheless, not all agencies have been willing to embrace scuba experiences for kids.

    Neither NAUI nor the YMCA — both nonprofit organizations in contrast with PADI and SSI — offer scuba programs for children less than 12 years of age.

    Frank Toal, of the NAUI training office, told Undercurrent that the agency found the medical and developmental concerns sufficiently compelling to preclude consideration of scuba for those less than age 12. Additionally, NAUI’s junior scuba certification, for ages 12-14, imposes a 60-foot maximum depth limit and requires supervision by a certified diver age 18 or older.

    Such reservations are not limited to these two training agencies and several experts have been outspoken in their opposition, most notably Larry “Harris” Taylor, Ph.D., a biochemist and Diving Safety Coordinator at the University of Michigan. His throughts on the topic can be found at www.mindspring.com/~ divegeek.

    World-recognized dive medicine expert Dr. Ernest Campbell has expressed misgivings about allowing his children to be certified at a young age, and said that he probably would have waited until their midteens if he had it to do again.

    So, what’s a parent to do?

    Admittedly the issues are complex. Yet it is clear, children face greater risks than adults. Parents or guardians must be thorough and responsible when considering whether to enroll in a PADI or SSI program. Any child being considered for a compressed air at depth experience or scuba certification should receive a pediatric examination with the expressed purpose of clearance for diving. The child’s psychological maturity for diving should be evaluated through open and honest discussions between the child, parent
    or guardian, and a knowledgeable instructor.

    If any party has substantial reservations, wait until these resolve. Under no circumstances should an unwilling child be coerced into scuba. If all signs are go, make sure the youngster has gear he or she can manage, wears adequate thermal protection, and is enrolled in a class of similar aged children.

    Finally, for those children receiving certifications with restrictions, ensure that all conditions are scrupulously observed. Attend the classes with your child and if you have any doubts about the child, the instructor, or the class, work them out or consider other classes later.
    —Doc Vikingo"

    Let me know if you have additonal questions.

  7. danceswithoctopus

    danceswithoctopus Nassau Grouper

    I am the one who began the thread about a year ago. (Thanks Doc V!) My research led me to more questions than answers, but the majority of the information I dicovered is found in this thread. It seems that there is no significant research into young divers and as has been said, there is significant and understandable reluctance to use youngsters as test subjects. Undoubtably as more young divers enter the sport, more information will be collected.

    Doc V's article http://www.undercurrent.org/UCnow/articles/Kids200109.shtml pretty much sums up the issue. But some other links I might suggest are: http://www.scubadiving.com/training/medicine/age&dive.shtml
    http://www.scuba-doc.com/teens.htm (there are a couple of good articles here)

    I also have an article in my file here entitled "DAN's Assessment of Medical Issues Associated with Children and Diving". I'm not sure exactly where I got it. Perhaps from DAN? If you have a hard time finding it, I might be coerced into scanning it and e-mailing it to you.

    My decision was to go ahead and certify Kris (who is the proverbial fish now), to adhere strictly and conservatively to the dive tables and the 40 foot depth limit (as an aside, Kris is aware of the issues involved and is as strong an advocate for conservative dive profies as anyone), and to never dive without an additional adult buddy: that is, Kris always dives with a third or fourth diver in the group. We never dive as a two-person buddy team. While this creates some logistical problems, it provides an added level of safety.

    We also reinforce to Kris that an aborted dive is a succesful dive. If there is anything at all that he feels uncomfortable about prior to a dive, we cancel. Since he certified last summer he has logged 12 dives and four aborts (two were his, one was mine, and one was another dive buddy).

    This is probably more information and less specific than what you wanted. But this thread has lasted longer than mine did, so I wanted to get this information out.

  8. DocVikingo

    DocVikingo Senior Member Staff Member

    Hi danceswithocotpus,

    Well, one certainly can't accuse you of entering into this uninformed. You've looked into it thoroughly, and structured a rational approach based upon the admittedly incomplete knowledge.

    If memory serves, Kris the Fish will be 11 in several months. I suspect he'll fare well under the limitations & precautions that you have established.

    Best of luck.

  9. danceswithoctopus

    danceswithoctopus Nassau Grouper

    Doc V,
    Thanks. Actually, Kris the Fish turned eleven a few months back. he is doing well. We are planning to dive today. It's good to hear from you. Your information was helpful in making the decision to allow Kris to dive as well as considering what restrictions and precautions to impose on his dives.
    Thanks again!
    (here's a pic for you of the little fish on his way to the wate.)
  10. DocVikingo

    DocVikingo Senior Member Staff Member

    He looks hardier than I.

    Best regards.


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