Subclinical DCS and Deco Dives

[Wormil]

Greetings Dr Deco!

It would appear that on many many dives I have the possibility of getting subclinical DCS. A typical profile would be ~70' for 20-25 minutes, a slow ascent with a minimum of a half stop for 2 minutes, followed by a slow ascent and an epic safety stop (~10 minutes). Total run time is usually around 45-55 minutes. All dives are done on nitrox, with appropriate mixes.

After most dives (including beach dives), I get extremely tired, and more often than not, I sleep for long periods of time. I do wake up feeling awesome though, like it was a well needed rest.

I'm curious if I actually am suffering from subclinical DCS, and if so, how much conservatism should I use in deco plans? Would O2 on the surface (or at 20') help?

 

[bleeb]

Another possible factor: What are your ascent rates, particularly from safety to surface, but also from bottom to half, and half to safety?

 

[Wormil]

Another possible factor: What are your ascent rates, particularly from safety to surface, but also from bottom to half, and half to safety?

Extremely slow. It's fun to watch people pass me to the surface. Total run time from line to surface is about 20 minutes I'd say, including the 2 minute half stop and the 10 minute safety stop.

 

[knotical]

While sub-clinical DCS might be one possibility, could it be as simple as loss of thermal energy? Even in pretty warm water we are constantly losing heat. That energy drain could make you tired. Perhaps increasing your thermal protection might help. I noticed a dramatic improvement when I started wearing a hood, even in tropical waters.

 

[Wormil]

Hmm. Need some Dr love up in this thread.

 

[dkktsunami]

The most annoying avatar yet ............

 

[Dr Deco]

Hello Readers:

Lethargy following a dive has yet to be identified with a single cause. Some do refer to it as “subclinical DCS.” The belief is that it could result from gas bubble formation. What the bubbles would actually do is not specified.

I have been involved with experiments [at NASA] involving human test subjects with many decompression gas bubbles [Spencer–Johanson Grade IV to be exact]. Largely, none ever reported lethargy or tiredness. I hear the same from my colleagues at the US Air force Altitude Laboratory.

My guess, and that of others, is that it involves physical exertion, cold, and mental stress.


Dr Deco :doctor:

 

[Wormil]

Hello Readers:

Lethargy following a dive has yet to be identified with a single cause. Some do refer to it as “subclinical DCS.” The belief is that it could result from gas bubble formation. What the bubbles would actually do is not specified.

I have been involved with experiments [at NASA] involving human test subjects with many decompression gas bubbles [Spencer–Johanson Grade IV to be exact]. Largely, none ever reported lethargy or tiredness. I hear the same from my colleagues at the US Air force Altitude Laboratory.

My guess, and that of others, is that it involves physical exertion, cold, and mental stress.


Dr Deco :doctor:

Hrm. So realistically, I should just plan deco dives as normal (+3 vplanner) conservatism and be a happy camper?

 

[Dr Deco]

Yup. And be a happy camper.

PS. terrible atavar!

 

[Scubagolf]

The most annoying avatar yet ............

It could actually cause a seizure.