Taravana??

[Lochmonster]

Was looking up info on www.scuba-doc.com when I saw an article on this type of DCS experienced by freedivers. Anyone know more about it? From the article and the links it has, seems to only affect divers doing dive in excess of 100 feet for 5 hours a day, like pearl divers. Also surface time of twice what your bottom time was seems to reduce the risk also (ie 1 min down, 2 min at the surface).

The article is here for anyone who wants more info:

http://www.scuba-doc.com/breathhold.html

[fpernett]

Hi,
Fred Bove published an article (I don't remember where) about it.
This word comes from symptoms that natives from Tuamotu archipielago in polynesia, suffer after freedives. They used to descent assisted by a weight and ascend pulling them selves in a rope thetered to their collection basket. The depths were from 30-40 meters and dive time around 1 and a half minute. The surface interval around 5 mins. The symptoms of Taravana are similar to that of decompression sickness (paralysis, visual changes, hearing loss, and even dead).
Dr. Paulev and Dr. Lanphier studied the nitrogen in tissues of freedivers, and the most important factors to avoid DCS is the ratio of surface interval to dive time and the rate of ascense.
The firts means that if you make freedives to some depth with low surface interval, is like you keep at a shallower depth but for all the time. For example a freedive to 30 meters of 90 seconds with a surface interval of 90 sec, is like a 15 meters continuous inmersion.
Of course all of this is theoretical and mathematical calculation, but there is many cases of DCS in freedivers. To my knowledge there is no well designed studies to document it

[peterk]

hi lochmonster, hi frank p,

I asked about the same thing under the title
'Was this Taravana, was I wrong to get drunk?'
a while ago.
please check my description of what happened,
Frank: would you give me an opinion?
I never went THAT deep, but my surface intervals were
short...


thanks!

...peter, www.juprowa.com/kittel

[fpernett]

Hi Peter,
I really don't know.
It's rare that you get recovered from DCS without Hyperbaric treatment. The Depleted Glycogen theory doesn't explain the sensorial disturbances.
The only thing that comes to my mind is something that people like Pelizzari has experienced, due to potent diving reflex.
When you are diving you shift the blood flow to the most important and low O2 reserve organs (brain and heart), so the blood flow in legs is very low, if any. After some deep immersions some freedivers can't move it's legs, that happen to No-limits freediving, too.
As I told you before, I don't know if it was that, but that's my explanation
Keep sailing

[shoutatthesky]

Where are the decompression table for freediving?

[fpernett]

nowhere!

This is a field with lot of things to know

[samdive]

in the AIDA 4 Star course there are now recommendations for preventing DCS from freediving. I don't have it with me right now but basically it involves longer surface intervals.

I've had a few DCS problems in the last few years and my docs have recommended 10 minute surface intervals between any freedives to 30m or more and between 5-10 for shallower than that.

[cdavis]

Sam,

I'd be real interested in AIDAs reccommendations for surface intervals for repetitive 25-35 m dives. What I heard through the grapevine was about 8 minutes for repetitive dives. How can I find AIDAs info?

Connor

[samdive]

You would learn it if you took an AIDA **** Course

here is the info:

As yet, no decompression tables have been constructed for freediving, but it is recommended to calculate the surface interval in relation to the depth.

SI in minutes = Depth in metres/5

30m - SI = 6min
40m - SI = 8min
50m - SI = 10min etc.

This should be applied not only to repetition at the same depth. For example, after a 50m dive the freediver should wait 10 minutes before he can safety dive for a buddy

[cdavis]

Thanks,

An AIDA couse would be fun, but not much available near here. I'm going to try and do a PFI refresher in the next year or two, or maybe Sebastion will give one of his courses near.

Thanks again,

Connor