flying question

[tigercrane]

hello-

I'm planning a trip to Belize for next month. The second half of my trip will be 7 days of diving.
I plan to do 7 dives. 2 days of 2 tanks dives. 1 day of 3 dives.
I was advancved PADI certified about 3 years ago and don't really remember how to determine when it's safe to fly. I never had to worry about it.
I will definitely not dive the last day but will probably snorkel.
Is that enough time to equalize? I knwo this is a lame question and I should know better but are there genral rules of thumb?

Thanks

 

[UWSojourner]

Here's what I do: let 24 hrs elapse. I'm assuming you're doing standard diving - no deco stuff. I think that's the current rule of thumb.

Snorkeling shouldn't be a problem if you stay on surface; if you're free diving I'm not sure whether that counts as diving (I would assume so).

 

[H2Andy]

yup...

24 hours from the last time you inhaled gas under pressure is a very safe margin,
and highly recommended. if you do the calculations yourself, however, you'll see
that 12 hours just about clears out all the residual nitrogen in your system.

i still like multiplying that by two. that's the Mr. Murphy in me.

by the way, not to be picky, but you don't mean "equalize."
that's what you do to your ears and sinuses to bring them on par
with the outside (water) pressure.

 

[DandyDon]

Divers Alert Network suggests a minimum of 12 hours, preferably 18 after multiple dives. From their site:

Current DAN FAD Recommendations

DAN's original recommendations for flying after diving based on maximum altitude exposure of 8,000 feet / 2,440 meters (the cabin pressure of commercial airliners) are:

A minimum surface interval of 12 hours is required before ascent to altitude in a commercial jet airliner (altitude up to 8,000 feet).

Divers who plan to make daily, multiple dives for several days or make dives that require decompression stops should take special precautions and wait for an extended surface interval beyond 12 hours before flight. The greater the duration before flight the less likely decompression sickness is to occur.

Current Research

Realizing that just about all current recommendations for flying after diving are based mostly on "best guess" and not hard data, Dr. Richard Vann and Dr. Wayne Gerth launched DAN's Flying After Diving study in 1993 at F.G. Hall Hypo/Hyperbaric Laboratory at Duke University Medical Center. The data so far suggest that the original recommendation of waiting 12 hours or more after making single no-decompression dives is reasonable.

In addition, current research suggests that it may be wise to wait 17 hours or more after making repetitive dives. However, the research is as yet incomplete and further work is continuing. More specific data on DAN's FAD recommendations are scheduled for a future issue of Alert Diver. The one unshakable truth is that the longer the surface interval after diving, the less the risk of DCS when flying afterward. Remember chamber trials are conducted within a relaxed, dry environment unlike the open water, where the multiple stresses of diving conditions may adversely affect the rate of inert gas uptake and elimination.

For more details: http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=54

If you do not have current Divers Insurance, this would be a good time to sign up. As I was loading a young newbie diver into an ambulance two weeks ago, I asked if he had DAN insurance? "Signed up two days ago!" That saved him a fortune on his two chamber treatments, and he learned to be a safer divers.

Snorkeling shouldn't be a problem if you stay on surface; if you're free diving I'm not sure whether that counts as diving (I would assume so).

Snorkeling on the surface is indeed no problem, however, Free Diving certainly can be! Such activities are strongly discouraged for the same period, just as strenous exercies is.

Besides, it takes 18 hours or more to dry my gear and pack it...

Have fun! don

 

[H2Andy]

hmmm... well, i can see how freediving doesn't help because since you're holding
your breath for 1-2 minutes at a time, the regular "off-gasing" is slowed down.

makes sense.

but why strenous excercise? would think that anything that makes you
breathe "faster" and "deeper" would probably help?

just shooting off the cuff; this is the first time i think about this.

(and by the way, i meant to say this in my earlier post, this is not a
lame question at all. in fact, it's a very good question)

 

[DandyDon]

hmmm... well, i can see how freediving doesn't help because since you're holding your breath for 1-2 minutes at a time, the regular "off-gasing" is slowed down.

makes sense.

No, not all - if I understand what I've learned here from Dr Deco about this. I think a good analogy can be made by viewing a can of hot beer - with CO2 disolved. Drop the can in the parking lot, then open it, and it's going to make a mess.

If you're still off-gassing disolved N2 from your blood & tissues, you want to do it slowly. Do some Free Diving and it's like banging around, then removing back pressure: The N2 is going to off-gas too quickly.

but why strenous excercise? would think that anything that makes you breathe "faster" and "deeper" would probably help?

just shooting off the cuff; this is the first time i think about this.

(and by the way, i meant to say this in my earlier post, this is not a
lame question at all. in fact, it's a very good question)

Again, it'll kick the N2 out of solution too quickly.

Run some searches on this forum for those phrases, and you should find better explantions from The Doc himself...

 

[H2Andy]

ah yes... it's sort of like doing a bounce dive, or a reverse profile dive.

now i see.

 

[Dr Deco]

Hello Scuba Board Readers:

Fly/Dive and Activity

I find it very interesting that the answers received from the readers indicates that there is an awareness of the problem of creating tissue micronuclei from physical activity. It warms the “cockles of my heart.” :54:

Curiously, there is not a set “bends/no bends” limit for a given diver. This depends on the activity level of the individual. It was very clearly evident from our NASA studies for decompression of astronauts prior to “spacewalks.” This effect was also noted by researchers during WW II (work from 1942-1945).

Therefore the NDLs used to make dive tables (and computers) are depended on the workloads of the test subjects both during the dive and following the dive. Since work is not customarily performed following a dive in a laboratory test series, such activity (if strenuous) would weight against you if performed during your actual surface interval.

Mild activity is good, however, since it promotes the flow of blood through the tissues.

Dr Deco :doctor:

 

[DandyDon]

I find it very interesting that the answers received from the readers indicates that there is an awareness of the problem of creating tissue micronuclei from physical activity. It warms the “cockles of my heart.” :54:

Yes, Sir! I've tried to pay attention when you share with us, try to remember it correctly, and then - try to explain it to others correctly.

don

 

[tigercrane]

thanks everone for your responses.
It's exactly what I was looking for.

I'm in pretty good shape and train martial arts everyday. would something like Tai-chi which is exercise but promotes great blood and energy flow be somethign to avoid as well after a dive.Or rather in the morning before a dive? It's a different kind of exercise than running. Would riding a bike from the dive shop to my cabana be concidered avoided exercise after a dive?
I'm trying to cover all my bases.

thanks again.