Are very slow final ascents better?

[BigTuna]

Try it, you'll even feel better........if you are feeling tired after diving, you are ascending too fast.

I read this from time to time. What's happening under the skin, if this is true? Does "tired" result from excessive bubbling on the boat? Does it have something to do with the red cells loading up with nitrogen so they can't function properly? Is this related to "dive Nitrox and you'll feel better"? What gives, anyway?

 

[The Chairman]

It's referred to as subclinical DCS. No aches or pains, no tinglies or other phenomena, just a tired and lethargic feeling. I honestly believe that ANYTHING that reduces N2 in your system helps, and that includes NitrOx. When you feel this way, a half hour on O2 and monitor yourself for any additional signs of DCS. When in doubt, let a doctor determine your status or contact DAN (from their website: www.diversalertnetwork.org)

Using the DAN Emergency Hotline
+1-919-684-8111 or +1-919-684-4DAN (Collect)

Whenever you need help, DAN is there. DAN's medical staff is on call 24 hours a day, 365 days a year, to handle diving emergencies such as decompression sickness, arterial gas embolism, pulmonary barotrauma, or other serious diving-related injuries. Each year, DAN answers more than 2000 calls on the diving emergency hotline from its members and divers.

When you call the DAN Emergency Hotline:

The numbers +1-919-684-8111 and +1-919-684-4DAN (-4326) are answered at the switchboard of Duke University Medical Center. Tell the operator you have a diving emergency. The operator will either connect you directly with DAN or have someone call you back at the earliest possible moment.
DAN's medical staff may make an immediate recommendation or call you back after making arrangements with a local physician or the DAN Regional Coordinator. DAN Regional Coordinators are familiar with chamber facilities in their area, and because they're qualified in diving medicine, they can make recommendations about treatment.
DAN's medical staff or Regional Coordinator may ask you to wait by the phone while they make arrangements. These plans may take 30 minutes or longer, as several phone calls may be required. This delay should not place the diver in any greater danger. However, if the situation is life-threatening, arrange to transport the diver immediately to the nearest local medical facility for immediate stabilization and assessment of his or her condition. Call DAN TravelAssist at 1-800-326-3822 at this time for consultation with the local medical provider.

 

[Fish_Whisperer]

Interesting, Pete. I had no idea that the post-diving fatigue was DCS-related. Thank you very much. Time to slow my ascents WAY down!

 

[rawls]

and they DON'T teach chasing bubbles any more.

Doc...I think, and please correct me if I'm wrong, even though alot of research is being done to modify and establish new parameters for ascent rates and deco stops, that an ascent rate of 60 ft/minute is still used by "some" agencies as a maximum rate of ascent along with a 3 minute safety stop, even though this new research is indicating it is too fast. The phrase "don't ascend faster than your bubbles" is very cliche, but I believe it still has some degree of vaidity to it.

 

[The Chairman]

Rawls,

NAUI teaches 30fsw/min and so does PADI and SDI/TDI. I am unsure whether ANY agency still teaches to double that (except in an emergency). Like I said, no one that I know of teaches chasing bubbles anymore! They are WAY too fast!

 

[Cacia]

A few years back, there was an article in JAMA about the subtle microscopic changes in diver's brains similiar to Organic Brain Syndrome. It was a little sobering and i think about that when I do those nice long stops.

 

[BigTuna]

NAUI teaches 30fsw/min and so does PADI and SDI/TDI. I am unsure whether ANY agency still teaches to double that (except in an emergency).

When I took OW in late 2004, my PADI book and instructor said (and I'm quoting from the book): "Swim up slowly, at a rate no faster than 18 meters/60 feet per minute (slower is fine),...." (The book I'm looking at has a copyright date of 1999-2003.)

I was talking to a PADI instructor and friend about this just now, and he says PADI (unlike NAUI) still teaches what I quoted. But you seem to be saying that PADI has changed its recommendation to 30 fpm. Would you please clarify this?

If/when PADI changes technical advice like ascent rate, how can divers get or check for official updates?

 

[BigTuna]

A few years back, there was an article in JAMA about the subtle microscopic changes in diver's brains similiar to Organic Brain Syndrome.

Do you recall if there were any detectable health or behavioral effects, or what intensity of diving was thought to produce OBS?

Side Bar: What's Organic Brain Syndrome, anyway? My brain is organic (currently), so am I sick? Is it maybe like mad cow disease?

 

[BigTuna]

The phrase "don't ascend faster than your bubbles" is very cliche, but I believe it still has some degree of vaidity to it.

I think I'll time some different sized bubbles at my next stop and see what I think....

 

[Fish_Whisperer]

Someone had a sig on here, some time ago, that read, The smallest bubble shall beat me to the surface. That might be a nice philosophy/practice to adopt.