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NEDU response to Sleepiness after diving

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New Member
Aug 9, 2002
I wrote the Navy Experimental Diving Unit again concerning the sleepiness some of us seem to get after diving. I told him that the deepest i've been since I started freediving was 12 feet. I also mentioned that I was a commercial diver and after every dive, I felt sleepy. Here is Capt. Southerlands response:

Off the top of my head, I think that your fatigue may be due more to
the effects of repeated exposure of the body tissues to low oxygen
(hypoxia), and high CO2 (hypercarboxia).

I'm not aware of a mammalian diving reflex exhibiting fatigue as a
predominant symptom. What's you heart rate on the surface? A diving reflex
should cause a really low heart rate.

If you were diving deeper, I'd consider DCS, but with a depth of 12
fsw, it tain't so. On the other hand, it would be extremely interesting if
it was, since it would blow everyone's theory of decompression sickness out
of the water (so to speak).

I'm off to a dive brief right now, but I'll think about it a bit
more and see if we have anything in the library. (I still think it's an
O2/CO2 issue though.)


PS All of this also assumes that there's not anything in the air at the pool
that could cause this problem, (like being next to the laughing gas
manufacturing plant, refinery, or other way-out-in-left-field situations).

I will keep you posted with anything he comes up with, guys and gals.

I just attended the NAUI Deep Stops Conference last month. This partly came up then. One of the doctors made the observation that alot of people in the gen population exhibit the "classic" signs of DCS and have never dove.:confused: ie. fatigue, soreness in their limbs, sleepiness, ect. The problem w/ these symptoms are they are very subjective and therefore vary greatly from person to person. So are these really reliable indicators for bubble trouble?
Also divers were given tests they were told were to test for mechanical brain injury. They didn't know they were actually being tested for possible Type II DCS--which most actually gave evidence of.
So-you know how to tell if a diver is lieing? His lips are moving.:eek:
We think we're bent when we're not, and we are when we say we're not.
I personally think that just spending time in an enviroment so foreign will cause various maladies in our body either real or imagined no matter how "natural" it feels.
Just my .02cts worth.
Its just for knowledge man! When we were cavemen, we asked "Grok, why sky look same color as water?" Why is apple pie good on christmas day? Its one of those things at least I want to know about.

to quote Thomas Dolby


When dived over 30m for the first time, I got back to the house and slept from 2pm to 10am the next day.

I was woken by my buddy who was phoning to find out if I was sleepy after the dive. Apparently he crashed out too.

I honestly didn't understand from the other posts whether this is normal or if it indicates some hideous injury.


Post dive fatigue

This is not unusual & though many have wrcked there brains on the subject a clear pattern does not emerge.

Cold may be factor, though observed in warmer water as well.
Depth would B an obvious factor - subclinical DCS, though it is noted even when dives do not exceed 30-40 ft.

A combination of factors, including respiratory work, CO2 retention & even sub-clinical DCS may need to be invoked.

As to the paper presented @ the NAUI Workshop - of the top of your head do U recollect who presented it & was there any discussion after it?


I can't recall specifically who presented the paper and there wasn't much discussion afterward. Since the topic was so subjective. The bottom line is it's really hard to tell borderline DCS, subclinical DCS, and just plain exhaustion. I get up some mornings and half of the signs of DCS and I have'nt dove in a couple of weeks. Also some of the comments about treatment were interesting. If a person shows up w/ these borderline symptoms and is treated they go away. Does that mean they're bent? Not necessarily. It's more the placebo effect. Everyone will feel better on 100% 02. Add a little pressure and they're cured. Divers w/ hangovers have known this for years.:duh That leads to the divers mental status. Were they worried about the dive, did they talk themselves into the symptoms?
My personal opinion is that the symptoms we use to determine DCS are in a gray area. I think a high percentage of divers today aren't prepared physically or mentally for the stresses of diving. That's why we see alot of these mysterious symptoms showing up. There also may be underlying medical problems not known that could be causing some of this. Since there is such a large diving population outside factors are surely being brought in to play. Unlike for example the Navy that has a set age bracket, through medical exams and a rigorous physical regieme. We have divers from 8-80 and every size and shape. Is this a good thing, I don't think so but thats just my opinion. But I'm not being driven by money to get everyone and their grandmother certified. Sorry for the digression. Take it for what it's worth.
Originally posted by Jay Styron
I get up some mornings and half of the signs of DCS and I have'nt dove in a couple of weeks.

We have divers from 8-80 and every size and shape. Is this a good thing, I don't think so but thats just my opinion. But I'm not being driven by money to get everyone and their grandmother certified. Sorry for the digression. Take it for what it's worth.

Does this mean you're giving me a chance next month? :crutch

And that second paragraph pretty much sums it all up. Very smooth. :cool: I just spent the last few weekends helping with some classes with students that had the best intentions, or whatever :confused: and for the life of me, I don't wanna be around if they ever actually jump... :head Trouble was that I'd look over at the other classes and Instructors :hmm and see more of the same. Kinda makes me want to get a good grip for when the next shoe drops in the legal sysytem, ya know?

Has anyone actually done any doppler studies on freedivers? It would be intersting to see what kind of bubble count they had after reporting these symptoms.

As far as being too out of shape to dive, I think that is VERY true in the scuba biz. There are so many grossly overweight scuba instrcutors around here that it's amazing more of them DON'T get bent.

I am not sure if the same follows suit with freediving. Most, if not all, of the freedivers that I have met take their fitness a lot more seriously than almost any of the bubble blowers that I know of. I just haven't seen a whole lot of 300 pound freedivers out there pushing the envelope.;)

I also wonder how cold affects all of this. I know that a few hours of winter spearing will leave me feeling pretty darn tired compared to the deeper dives I do in the summer time.

Hydration must also play a role. I know that I have more stamina playing underwater hockey if I have a bottle of water on the side of the pool, and make sure to drink from it every so often. It amazes me how hot you can get while swimming around in a pool for an hour or so.

Yea,, it's like the saying I just heard, "money is a great servant, but a terrible master". Now they're certifying kids 10 yrs old. Gimme' a break. What next 12 yr old adv. divers, 15 yr old Trimix. Don't laugh, it could happen. And so what if the person has epilepsy, diabeties and maybe 100 or so pounds over weight and hasn't dove in 2 yrs, by God it's their legal right to dive and for a price someone will certify them or take them out. Sorry if this sounds harse but I've seen it happen and unfortunately the effects. :(
Hydration and temp are absolutly legit factors in DCS suseptability, Jon as is the waistline. 15 yr old trimix certs... I hope the kids don't hear about that. One person in the family with necrosis is plenty. :mute

15 year old trimix? does that work for 16 year olds too?

the trick isnt going to be passing the course, its gonna be getting my parents to sign on the dotted line:duh (next to impossible)
on a second note, i was talking to some kid with a c-card, we get on the subject of gear and i asked him if he had his own set of regs. he replies "no, my dad has a computer thing, we dont use that reg card anymore":confused:
turns out he thought "regs." were regulations (ie he thought they were the dive tables)
this kid was only a "jr diver" or whatever padi calls it (when your under 15, he was 14):ban

sven, does your oldest one dive?:D (shes about my age;) )
Yeah Sven? Does litte Svenena Dive? :blackeye

I have an article around here someplace on the adverse effects of pressure on developing tissue. basically a Dr.'s FIY on child divers. very interesting reading, especially the parts on tissuse growth rates and stunting. I'll see if I can dig it up

Hydration has always been a big deal with our divers. at 110F - 130F in the air with 90% humidex you sweat like a pig. we make them guzzle the water before every dive, they get pissy and don't like it, but the ocean water is 93F and makes for little or no relief.

Anyone know the age limits for PAID, sorry PADI... Tech Deep? I don't have the standards, but hear it's pretty young.

Naui might say different but I don't train divers younger then 15.

Would love to hear the Doppler results on Apnea/freedivers. Very curious....

heard from a PADI boardroom...

"Lessee, by age 10, they'll have savings from a paper route... how can we get that revenue...?" :hmm

Scuba Rangers!!!!

this is how we get that revenue. I try not to compare apples to oranges most of the time, but when I was a commercial diver, I was looking for extra insurance, just in case. I called DAN. I told them I was a commercial diver, and got a big NOOOOO!

It didn't matter that I had to take a physical once a year, if not more (at the request of the customer), frequent urine tests, annual long bone x-rays, not to mention that you can be disqualified from commercial diving if you are overweight.

I ask you, how many scuba divers out there get annual "DIVING PHYSICALS" ? The diving physical is a totally different animal than the old blood pressure, questionairre, and cough test.
Originally posted by TMcKee
I ask you, how many scuba divers out there get annual "DIVING PHYSICALS" ?

Moi! and 2.5 hours after I entered the Dr.'s office I comeout and sleep for half a day.

I hate those things.......

Willer :hmm
I might get spanked for this.....

I started diving when I was 14- that was the age limit back then. I started my instrcutor training when I was 17 and the course finished a week after my 18th birthday- got in just under the wire. I never had a problem and my bones and joints seem to be just fine after 20+ years of diving. ;)

PADI allows discover scuba's with kids as young as 8 and certification for kids as young as 10- with, I believe, a 40' depth limit.

Since I AM a third grade teacher, I make sure to take my students scuba diving in the highschool pool every year when I get to the Titianic chapter of our reading book. I take the kids into the water 4 at a time, and keep them in less than 6' of water the whole time, per PADI standards. I have been doing this for about 4 years now, ever since they first allowed it. All of the kids do great and they really seem to enjoy the whole "experience". That's what it really is, an "experience".

I have had parent's come up and ask me afterwards about certification and I always decline. I feel more than comfortable letting them blow bubbles and talk to eachother in a 4' deep pool with me watching, but not one of them is mature enough for ME to sign off on their C-card. I have run close to 300 kids through this without a single problem; however, sending a kid out diving with their recently certified parent is just asking for trouble.

you want a laugh? Let me explain to you in horrid detail about the commercial divers physical.

Starts with the hearing test, which they tell you the same thing every time. "Diver has low to mid range hearing loss, he must wear ear plugs when around any machinery"

You get the old lung volume test to see if you can use a respirator. Which you must pass. If you don't, you are disqualified from diving.

Eye test, long bone x-rays, and not the good kind of long bone, the real long bones of your skeleton. Then you get a spine x-ray, and that damn machine sits right under the vent so when you press your chest up to that metal/plastic plate, you come out pointing your nips at everyone.

Blood, Urine tests, Blood Pressure test...so what.. Then you go to the exam room....:(

The doctor comes in, and you have to strip to your underwear. At this point he does a neurological exam to see if you are okay. After the largest portion of the neurological exam, you have to take off your underwear and lie down on the table, face up, I add.

The doctor then takes this pointy roller thing and says, "tell me when you dont feel this", and proceeds to roll this thing up and down your body. He will skip over parts and you have got to tell him that you didn't feel it, apparently, he has had divers lie to him.

When he gets to that most sensitive of areas, he grabs your boys and lifts them, and rolls that pointy thing under them in that area between...well... While your boys are in his gloved hands he will roll this pointy thing down your legs, which makes you wonder..."why does he still have my..." and as soon as you think it he moves back up and does the other leg. You turn over on to your stomach and he repeats the process, including a cheek spread.

If this isn't bad enough, then he takes a ticklish thing, like the end of a feather and runs this up and down in the same areas, and again, your boys are in his hands and he is using this tickling thing under there... This is the hardest part for me... I giggle like a little girl.

So as the humiliation sets in, you are instructed to get off of the table and bend over it. He goes for the KY and a new glove. You turn around slowly like a child about to get a spanking. He instructs you to spread em and with one hand on your shoulder, or was it two?.... PROSTATE TIME!!!!

Once the deed is done, wondering why his finger is so large, you are left to get dressed and then he comes in to talk to you about the results.

After my first physical, I wanted to go to the police and press charges.
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