+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 11 to 16 of 16

Thread: Decompression and body composition

  1. #11
    Andy Pitkin apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin is just really nice apitkin's Avatar
    Join Date
    Feb 2005
    Location
    Gainesville, FL, USA
    Posts
    317
    Prism 1

    various

    Re: Decompression and body composition

    The big confounder in relating body fat to decompression risk is exercise. There is quite a lot of evidence now pointing to a protective effect of exercise. Jon Broome showed this effect elegantly in a porcine model of severe spinal DCS where he found that sedentary animals had nearly twice the risk of suffering severe DCS than those that exercised (IIRC) to 60% of max predicted heart rate once a day for about 30 minutes. The neat thing was that he showed that there was no difference in body fat between the two groups.

    Alf Brubak has shown similar results in rats, although it's not a new observation in rodents:

    Cross-adaptive effects of cold, hypoxia, or physical training on decompression sickness in mice

    How long, how much and what kind of exercise you need to get the protective effect (which can be significant) is not exactly clear. Doing regular exercise and including a session within the 48 hours before the dive is probably the best currently available advice.

    I think it's safe to say that there is not a simple relationship between body fat percentage and DCS risk.


    Andy

  2. #12
    RBW Member jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk has a reputation beyond repute jkaterenchuk's Avatar
    Join Date
    May 2006
    Location
    PA
    Posts
    2,942
    HammerMeg

    Kiss Classic, Inspiration

    Re: Decompression and body composition

    Quote Originally Posted by aainslie  View Original Post
    John,

    Why did you increase the deep gf from 20 to 30?
    Andrew

    Nothing scientific. There was another diver on the trip that had been in the study earlier in Grand Cayman and had exactly the same result as I did on deep dives. He was also using 20/85. He decided to change to 30/85 and the post dive results improved in a similar fashion to mine. So I decided to do that also. There was not enough time to try different combinations. If I get to participate in the study again I would try some others.

    I think I know why your asking and I quess all this flys in the face of deep stops since the change from 20 to 30 eliminates a deep stop or two depending upon depth so it gets you shallower quicker and then the 85-75 keeps you there a little longer. All I can say is the screen showed the results and anyone looking at it would be as surprized at the magnitude of the impact as I was.

    John

  3. #13
    Dave Tomblin wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc's Avatar
    Join Date
    Feb 2005
    Location
    Vancouver Island BC Canada
    Posts
    3,785
    Hollis Prism 2, Megalodon

    CCR Instructor Trainer

    Re: Decompression and body composition

    Quote Originally Posted by aainslie  View Original Post
    John,

    Why did you increase the deep gf from 20 to 30?
    wouldn't that follow the same logic as your fast ascent on deep dives.Reduce ongassing slow compts at depth.
    Cheers,

    Dave....

    www.wedivebc.com

  4. #14
    TRITON Dive Team, Serbia danijeladir is an unknown quantity at this point danijeladir's Avatar
    Join Date
    Dec 2009
    Location
    Belgrade, Serbia
    Posts
    28
    pSCR Satori

    Ispiration

    Re: Decompression and body composition

    Quote Originally Posted by jkaterenchuk  View Original Post
    In general terms it would always be better to have all the known/suspected factors aligned in your favour for the best decompression results. The problem comes when you try to do that in reality and want to make a decision like should I reduce from 15% body fat to 10% body fat. And if I go thru that long term reduction and effort how much of payout do I get with decompression efficiency. And how does that improvement in efficiency compare to a simpler more immediate result like changing my VPM or GF to be more conservative.

    Last time I had a body fat analysis I was around 16% so I know it would take several months and alot of time/effort to get down to 10%. But I know immediately I can get a significant improvement by changing from 20/85 to 30/75 and it only adds a little additional time to my decompression time in the water.

    John
    John you are right of course. changing the dive plan will have greater (and imidiate) impact on your deco. Also going from 16 to 10% of BF is hard. You can reach that goal in many, more or less healty ways. Training, diet, "chemicaly assisted" etc. But this should not be the main goal. A good training and food plan can bring you a long way, and at the end if you reach that 10 or whatever BF% I am positive you will be more efficient during deco. Not only because of your BF but because you have a more efficient and healty body. It is just a peace of a puzzle and it should not be overrated.

    Mirko

  5. #15
    RBW Member gsk3 is on a distinguished road gsk3 is on a distinguished road gsk3's Avatar
    Join Date
    Jul 2010
    Location
    Philadelphia, PA
    Posts
    27

    Re: Decompression and body composition

    Quote Originally Posted by jkaterenchuk  View Original Post
    Now I believe that the major risk with DCS is dive profile. Hydration, Fat %, age etc are all smaller contributing factors.
    Hard to see how you can come to this conclusion from your anecdote.... Everyone else on the boat was presumably diving similar profiles. So individual variability clearly matters. But does obesity matter above and beyond individual variability?

    Here's a chunk of evidence on that question:
    Search

  6. #16
    Markku Diedrich Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure is a glorious beacon of light Fun Under Pressure's Avatar
    Join Date
    Nov 2006
    Location
    Switzerland
    Posts
    3,220
    Megalodon Apeks 2.5

    Classic Inspiration

    Re: Decompression and body composition

    My buddy and me we where in south france for wreck diving, JP Imbert come with a second dr to do some examination of the divers, after every dive we had a bubble detection via a thoracic ultrasonic examantion, my buddy is 195 cm high und he weight arround 140 kg, i am 175cm high and i weight 86 kg, after the second dive ( 100m ; 20 min bt, 3 hours dt) i have had a few small bubbles and my buddy have nothing,.... since then i am not sure if fat means you are more in the risk of getting dcs,....after the third dive, same profil, we both have nothing...

+ Reply to Thread
Page 2 of 2 FirstFirst 1 2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts