[440634]

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<font color='#32CD32'>STOLEN QUOTE FROM ANOTHER THREAD...............

Have you ever seen a skinny marine mammal? Surely as divers we are all following the natural tendencies of mammalian species which maintain body heat by surrounding vital organs and muscle with a layer of blubber....   fat divers is nothing more than natural


Interestingly though, during a conversation with another diver that is involved with all agencies and regularly liaises with DDRC and similar I was told that most studies have shown that fat should not be thought to be a pre-disposing factor to DCI in fact almost the opposite, that it seems it's the skinny people that tend to get bent - possibly due to coldness affecting their off-gassing.

What's your view?

Been bent?

Know soneone that has?

Juz

 

[Kate R]

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<font color='#000080'>depends whether fat equates to unfit.....

which it normally does with us, unlike marine mammals!

 

[louigi]

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<font color='#FF0000'>I saw in one of my books an advert for a club for bent divers dorothy divers or am I getting it wrong some where.

 

[BSH]

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<font color='#0000FF'>Louigi

Definitely getting it wrong  

FB

 

[Chardy]

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<font color='#FF0000'>I am normal on the BMI scale, I do feel the cold, low body fat - sub 10%, and I have been bent. I was'nt cold dive, it was a summer dive, relevant factors were dehydration - hot day and previous days' activities, pushing computer to limit without hitting deco and increased activity underwater result two days at the DDRC. The cold issue does concern me as I have moved onto to Trimix and extended deco is something to deal with, don't want to get fat to deal with the issue so I am thinking about a new 03 RI drysuit and a weezle extreme, depends on my tax rebate !

 

[Dr Stevil]

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I'm assuming the original poster was being pretty much tongue-in-cheek,  it's not possible to seriously compare an overweight land mammal with a marine mammal who's exibiting the natural processes necessary for it's extensive adaptation.

Although I'd be interested to see facts and figures from the DDRC on weight and DCI correlations, it's too simplistic to merely assess by relative BMIs as this measure does not account for which tissues make up the body mass, plus some overweight people may have better CV fitness than a thinner person and I'd reckon that's more likely to be a factor than a few pounds of lard.

As for divers temperature and off-gassing, the core temperature of the diver is still going to be around 37 deg C (or they're in trouble!), but also, being thinner doesn't necessarily mean being colder, I've seen plenty of divers more "substantial" than me being cold in conditions I thought were fine
Chee-az
Steve, BMI 25.8, never been bent, rarely cold in the water

 

[bang-on]

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<font color='#0000FF'>diver early last year cv fit,young,capable,experinced o/c trimix got a bend on a conservative profile in good coditions??
dont figure!!  
result 3 months,no diving.
cheers
barrie

 

[Mark Powell]

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I'm definitely with Kate R on this one. I think fitness is a key issue.

If you are fit then your perfusion is better and this is a key factor in offgassing.

When you exercise regularly your body increases the flow of blood to your tissue by 'growing' additional blood vessels. Forgive the non-medical explanation, I think the technical term is something like angiogenesis.

On the other hand if you are cold then the body shuts down blood supply to non-essential areas which will then limit offgassing in these areas.

However there are a number of theories that claim that being overweight is indeed a disposing factor to DCI. Fat is a 'slow' tissue as it is very poorly supplied with blood vessels and so can act as a reservoir of nitrogen which is just not present in a slimmer diver.

I also remember reading an article that claims that, as there were no nerves in fatty tissue, it was likely that bubbles could form in fatty tissue with no immediate effects and then only show up later if it get into the blood stream.

Like most deco theory most of this is conjecture. I would love to see any solid research that DDRC have carried out.

 

[440634]

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<font color='#32CD32'>I was suprised by the conversation.

I did not mean that any research had been done, just that people in the know were saying 'hearsay, third hand etc) that in cold water, being cold was a bigger factor in DCI than most people realised, and that fatter people tended to maintain body warmth more than skinny people.

 

[Mark Powell]

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Yeah I can see that bit makes sense.

Swings and roundabouts I supose.

I'm going to carry on going to the gym AND wear extra thermals.

 

[Chardy]

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<font color='#FF0000'>I take the point about the fitness thing and I do a lot of training - 10K sub 36 minutes, low resting pulse etc so CV wise I'm fit, so when finning into heavy currents I can deal with the extra CV load placed upon me but part of the problem from my bend was the extra nitrogen loading from increased workload and that's where I got caught out.

The other bonus from being fit is that I feel that my air consumption reduces the fitter I get from being more efficient.

 

[Mark Powell]

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DCI is definitely a complex subject. There are just so many factors that can contribute. I always teach that you should try and reduce as many of the predisposing factors as possible. This includes amongst other things

- Dehydration
- Unfit
- Overweight
- Cold
- Workrate
- Ascent rate
- Repetitive diving
- Stress
- Dive profiles
- etc, etc, etc

It's difficult to focus on just one or two of them. The fittest diver in warm water can still get bent if they are dehydrated or in your case working hard.

 

[Dr Stevil]

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Getting back to the DDRC, it's unfortunate that the Diving Diseases Research Centre doesn't actually possess any funds to support research into diving diseases! I know because I spoke to them a couple of years ago to investigate the possibility of working in this area. Therefore their research is pretty much limited to questionairres, surveys and collation of data garnered by the technicians who run the various chambers around the world. This is a pity because there's bound to be a selection of biochemical and genetic predisposing factors which could be examined. I'd be particulalry interested to look at the formation of free-radicals in recreational diving as all the factors which predispose to DCI are all linked to increased free-radical formation.