Why not sleep during surface interval?

[Newhampster]

A 6 hour window between diving and heavy exercise is recommended to dramatically minimize any incremental risk.

[Not an expert, remember reading this from some detailed discussions of all the issues. Don't have the citation so I'm trusting my memory. At my age, I should know better...]

Caveat Emptor

 

[earl]

Can somebody be more specific about heavy exercise? I consider myself to be in decent shape (weights = 190/310/270 as a rep / I can run a 5:00 mile) -- so is it heartrate or what determines heavy? And how about aerobic vs lifting?

-earl-

Edit: remove accidental icon selection

 

[Ari]

Should one keep awake for a few hours after getting out of the water? If so, than what is the recommended NST (No Sleep Time)?

Ari

 

[DocVikingo]

Hi Ari,

One needs to exercise good sense about this advice. The relationship between sleeping/being sedentary following a dive and sustaining DCS is a not well-studied & seemingly weak one.

If staying awake for several hours after a night would result in dangerous fatigue for the next day's diving, then you'd probably be better off going to bed straight away. If you can remain awake & mildly active for a couple of hours after the night dive & still be rested & alert the following day, then it's best to do so.

Best regards.

DocVikingo

 

[pipedope]

I think you can also factor in the nature of the dive.
Example, 45 minutes at 30 FSW is way far from NDL so the risk of DCI is very low. In this case a shorter observation period should be fine.

If you are pushing the limits or doing any dive with a decompression obligation then you should stay awake. You can only notice the symptoms of DCI if you are awake.

Remember that dive planning includes the preparation and the recovery from the dive, not just the time under water. Build in the time needed for observation and things like cleaning and stowing gear when you plan a dive and it will all go more smoothly.

I have done lots of dives with excersize or sleep right after getting out of the water but they were on the order of 45 minutes at 20 feet or 30 minutes at 30 feet and DCI risk was nearly nonexistant.

michael

 

[Ari]

With all the activities post dive, it'll probably take some time before actually going to sleep.

Pipedope, you are also right by saying that a night dive will probably be far from the NDL, so the risk of DCS is relatively small.

I will have to revisit this problem when my night dives will get somewhat more challenging.

Thanks guys.

Ari

 

[Dr Deco]

Dear Readers:

With regards to not sleeping in the surface interval between dives, the simple fact is that heart rate and perfusion (= blood flow) will slow, and you will perform the next dive with more gas than you planned.

At night, naturally one needs to sleep. I would not expect one to make a strenuous dive that late. There was a time when the U.S. Navy did not continue with the decompression from saturation during the night sleep interval. I do not have a reference to this. I do not know if this is still current policy. ( I am mostly in the space business now.)

How “statistically significant” this is might be hard to say since the incidence of DCS in recreational scuba is very, very low. However, it is a very significant factor in test subjects at NASA when altitude decompression is concerned.

Dr Deco
:doctor: