Hospital of St John & St Elizabeth WHATISBOBO

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Hello, I wonder if you can help. Our son is 15 and we want him to take up diving. He is a shy boy, not sporty at all, and very into his computer games (we think unhealthily so). He doesn't do any physical activity and due to his predominantly indoor lifestyle has recently been diagnosed with vitamin D deficiency - we were shocked to learn that rickets still exists in the UK! This has been a wake-up call for all of us so we are trying to encourage any form of outdoor pastime, and Jonny has expressed an interest in diving before. He is on replacement supplements now but does his diagnosis pose any risks as far as diving goes? Thank you for your advice.

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The rise of rickets in the UK is indeed concerning and unfortunate. Once the scourge of Victorian Britain, the disease was virtually eradicated in the 1950s, but has returned for a number of reasons, principally that which your son typifies - increasingly long periods spent indoors, and correspondingly little exposure to natural light. Vitamin D (which is actually a group of steroid hormones) is crucial to the normal formation and growth of bones, by enhancing calcium absorption from the gut; and its activity depends on sunlight (specifically UVB radiation). Hence the other main factor in the increasing incidence of rickets - suncreams, which block UVB so effectively that vitamin D synthesis is impaired. The resulting symptoms include curvature of the spine, muscle weakness, increased bone fragility, and the characteristic bow legs and deformed chest.

Happily the condition can be corrected simply by vitamin D supplementation and sunlight; so a diet rich in fish oils and some outdoor activities are all that is usually required. None of this should preclude diving, so if Jonny is keen then I would be doing anything you can to encourage him.

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I am going to Thailand for 3 weeks in February and I am planning to do a 7 days detox fasting (no solid food just fruit juices twice a day) at a spa in Koh Samui. I am a 35 years old healthy female, 170cm height, 60kg. I am also quite keen on doing some scuba diving while I am doing the fasting, at least the first few days and if of course I have the energy. Do you think this is dangerous?

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My theory is that you can tell how good a nation’s food is by the amount of restaurants in London. No Chilean, some Brazilian, but a hell of a lot of Thai. Good luck in the culinary capital of the world, starving yourself. But I have to say, if you dive and starve, you’re gonna risk a fine blend of DCS and cramps. Fruit juice twice a day, is not enough fluids in a hot climate. If you dive dehydrated, then there is an issue that you wont be able to off-gas your nitrogen as easily. Likewise, not enough carbos, then a difficult energetic dive, and you could cramp up.

So as you have a 3 week trip there, detox merrily away, but do not dive. There’s plenty of time in the other 2 weeks to do that when you are eating and drinking healthily. Spend your time in that week, helping the C-list celebs examine the results of their colonic irrigation. Aaah, isn’t that duck pate from the Groucho.

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I am a 26 year old female with anorexia nervosa. Been diving since I was 14. Just got an ECG test back that said my heart rate was slower than normal (in the 50's). Does this put me at increased risk for diving? I am going away for the next two weeks and was hoping to dive - is it safe?

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Anorexia nervosa is not a new illness. “Fasting girls”, a Victorian term for non-eating pre-adolescents, have been around since the Middle Ages, and were often claimed to have miraculous or magical powers, usually by exploitative museums. Sadly, whenever these claims were tested, the girls in question starved. Today the condition is a formal psychiatric diagnosis, an eating disorder that causes low body weight, body image distortion and an obsessive fear of gaining weight. In general terms, the problems that this would cause for diving are several. Reduced strength and exercise tolerance are common, meaning kit-carrying and hard finning may produce early fatigue. Psychological issues might jeopardise safety, with panic and phobic behaviours a prominent feature. Any medication taken for the disorder might have repercussions also.

As far as your specific heart rate query goes, a slow pulse can be a sign of a very fit heart. If the ECG is otherwise normal then the rate itself would not put you at any increased risk of diving problems. Nevertheless, I would suggest you are cleared by a diving doc, for the reasons outlined. The fact that you have been diving for 12 years should be in your favour though.

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