Perfect ascents - your view

[*Helen*]

Hi all,

Having spent a few days reading this board, I'm shocked at how little of this wisdom and research has filtered down to training. I'm currently on a PADI o/w course and there was no mention of
(a) the role of exercise, either before or after diving, or gentle (beneficial) vs. vigorous (harmful) post-diving.
(b) the slow-ascent curve (slower nearer the surface)
(c) the fact that dive tables are essentially PROBABILISTIC.
All of these seem important, given the knowledgable posters on this board.

We have our open water dives (10m & 18m I believe) coming up soon. I would like to know what you believe is the perfect ascent from these depths. (Current PADI wisdom is a safety stop at 5m/16ft and ascending at an 18m/60ft per minute rate all the way.) I have noticed that some of you put in more than one safety stop, even for relatively shallow dives. Would your perfect ascent profile include this, even at an 18m or 10m dive?


(The reason I'm concerned is that we did 4 padi modules at the bottom of a pool in a row, with several ascents but no surface interval to speak of. This followed fairly vigourous exercise (ie plenty of equipment hefts) and was followed by the same. I'm well aware that the likelihood of DCI is remote at this depth (4m) but about 2hrs later, there was slow onset of shoulder pain, until I felt like I had been hit in my shoulder by a sock full of lead weights. Pain increased to level of nausea & near-retching by 6hrs later. Was not a muscle issue - at least, it certainly didn't appear to be as it did not increase on any particular movements, and there was no sudden onset as there is if you pull a muscle or it goes into spasm, and there was no muscle tenderness at any time. Also, I was very thirsty due to being in a rush to get there on time and not taking any water since I woke up (oops).

Ok, I know it is still unlikely, but whether it was a bend or not I'd still be interested in your individual views on the perfect ascent from 10m and 18m (?33ft & 60ft).

I would like to practise good ascents from the start of my diving history - and maybe discuss alternative thinking with my PADI ow instructor & group....

Helen

 

[GeekDiver]

The 60ft per min is the max rate of assent. It is recomended not to exceed this established rate, not to actualy assend at this rate. Slower is better. Most dive computers actualy have assent rates much slower (30ft per min Max) and would error out if you assend at 60 ft per min. I almost always make a safety stop no matter the depth. I use this time to practice skills such as reg exchanges, hovering etc. I try to asend the last 15 ft at very slow rate. Remember that it should take at least 15 seconds or more even under the 60 ft per min rule which is 1 ft per second. If you pop up to the surface in say 5 seconds then your asent would rate would equal 180 ft per min which is in violation of established training.

If your concerned about your pool session you can always ask the experts at DAN or check with your Doctor. I would also encourage to ask your instr about this as well.

 

[Saturation]

Hi all,

Having spent a few days reading this board, I'm shocked at how little of this wisdom and research has filtered down to training. I'm currently on a PADI o/w course and there was no mention of
(a) the role of exercise, either before or after diving, or gentle (beneficial) vs. vigorous (harmful) post-diving.
(b) the slow-ascent curve (slower nearer the surface)
(c) the fact that dive tables are essentially PROBABILISTIC.
All of these seem important, given the knowledgable posters on this board.

We have our open water dives (10m & 18m I believe) coming up soon. I would like to know what you believe is the perfect ascent from these depths. (Current PADI wisdom is a safety stop at 5m/16ft and ascending at an 18m/60ft per minute rate all the way.) I have noticed that some of you put in more than one safety stop, even for relatively shallow dives. Would your perfect ascent profile include this, even at an 18m or 10m dive?


(The reason I'm concerned is that we did 4 padi modules at the bottom of a pool in a row, with several ascents but no surface interval to speak of. This followed fairly vigourous exercise (ie plenty of equipment hefts) and was followed by the same. I'm well aware that the likelihood of DCI is remote at this depth (4m) but about 2hrs later, there was slow onset of shoulder pain, until I felt like I had been hit in my shoulder by a sock full of lead weights. Pain increased to level of nausea & near-retching by 6hrs later. Was not a muscle issue - at least, it certainly didn't appear to be as it did not increase on any particular movements, and there was no sudden onset as there is if you pull a muscle or it goes into spasm, and there was no muscle tenderness at any time. Also, I was very thirsty due to being in a rush to get there on time and not taking any water since I woke up (oops).

Ok, I know it is still unlikely, but whether it was a bend or not I'd still be interested in your individual views on the perfect ascent from 10m and 18m (?33ft & 60ft).

I would like to practise good ascents from the start of my diving history - and maybe discuss alternative thinking with my PADI ow instructor & group....

Helen

Hi Helen:

You a-c points are right on. Kudos to your readings and sifting signals from the noise.

You describe the current OW diving curricula which is accepted, but dated.

Reflecting only on recreational diving, your ascent rate should not be more than 30fpm across the whole dive, this is established to be a 'safer' ascent rate. Stick to this rate as best you can.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8574124

From 20-0', is controversial. There is suggestion than slower is better due to percentage change in bubble size in this region but no data to support it. In general, when doing the safety stop at 20', the longer the stop the more reduced the surfacing bubbling becomes, that is 5 min is better than 3, and 10 is even better. Bubbles are reduced the most at 5 min for the time spent, and are less reduced between 5-10min, so it terms of spending time here, its a trade off between offgassing and a need to surface.

A simple plan is do 3 minutes at 20', then ascend at 10fpm to the surface. This distributes the 5 min safety across the ascent.

Yes, luckily DCI at 4m is nearly impossible so maybe the pain and discomfort was a combination of muscle sinus barotrauma or minor ear infection.

A deep safety stop is beneficial. Current data suggest it be 5min, further testing is needed to see if 2-3min here alone suffices. However, any stop here is better than none at all. Its easiest to calculate as half your maximum depth, so it makes sense to do such stops >= 60'.

 

[jbd]

Hi all,

Having spent a few days reading this board, I'm shocked at how little of this wisdom and research has filtered down to training. I'm currently on a PADI o/w course and there was no mention of
(a) the role of exercise, either before or after diving, or gentle (beneficial) vs. vigorous (harmful) post-diving.
(b) the slow-ascent curve (slower nearer the surface)
(c) the fact that dive tables are essentially PROBABILISTIC.
All of these seem important, given the knowledgable posters on this board.

We have our open water dives (10m & 18m I believe) coming up soon. I would like to know what you believe is the perfect ascent from these depths. (Current PADI wisdom is a safety stop at 5m/16ft and ascending at an 18m/60ft per minute rate all the way.) I have noticed that some of you put in more than one safety stop, even for relatively shallow dives. Would your perfect ascent profile include this, even at an 18m or 10m dive?


(The reason I'm concerned is that we did 4 padi modules at the bottom of a pool in a row, with several ascents but no surface interval to speak of. This followed fairly vigourous exercise (ie plenty of equipment hefts) and was followed by the same. I'm well aware that the likelihood of DCI is remote at this depth (4m) but about 2hrs later, there was slow onset of shoulder pain, until I felt like I had been hit in my shoulder by a sock full of lead weights. Pain increased to level of nausea & near-retching by 6hrs later. Was not a muscle issue - at least, it certainly didn't appear to be as it did not increase on any particular movements, and there was no sudden onset as there is if you pull a muscle or it goes into spasm, and there was no muscle tenderness at any time. Also, I was very thirsty due to being in a rush to get there on time and not taking any water since I woke up (oops).

Ok, I know it is still unlikely, but whether it was a bend or not I'd still be interested in your individual views on the perfect ascent from 10m and 18m (?33ft & 60ft).

I would like to practise good ascents from the start of my diving history - and maybe discuss alternative thinking with my PADI ow instructor & group....

Helen

I teach 30 feet per minute or slower with 3 minute safety stop at 15 feet. From 15 feet try to go very slow as noted by GeekDiver.

NAUI has introduced at stop at half the max depth of the dive(I think for dives greater than 40 feet) for one minute and then 2 minutes at 15 feet with a 30 fpm ascent rate. This goes along with dual phase gas models.

 

[*Helen*]

Hi,

Thanks for your input. I think I understand the theory & am interested in how you guys put your understanding into practice. So it looks like your *ideals* for a shallow dive (10 - 18m) are:

Everyone max. ascent rate 30 ft / 9m per min.

Saturation's ideal: 10min stop at 20ft / 6m, very slow ascent rate from there 10ft/3m per min. I think I understand you as saying ideally do a deep safety stop if you're going to 18m or below, >=60ft, in which case do it at half your depth, so in this case it would be at 9m/30ft. That's cool & thanks for your input which I found very helpful.

jbd & Geek: 3 min stop at 15ft /4.5m, very slow ascent thereafter. Jbd - short stop at half max. depth after 40ft / 12m?


Saturation - thanks for the link to the exercise/ascent rate rat paper. It's really great that research seems to be taking off in this area and that there are things to quote at people! I don't want to come across as the pushy one on my course, but to be honest I've not been impressed and we're talking about serious issues & research. Re. my symptoms - not sure how an ear infection can relate to shoulder pain??

Does anyone think the PADI o/w course should be updated soon? I'd like to know how often their trainers have to be updated with the latest research, or if they just have to know the current syllabus.

OK well we're diving off the UK coast this weekend - hope the gales have left us some visability.

Helen

 

[Saturation]

Hi,
Everyone max. ascent rate 30 ft / 9m per min.

Saturation's ideal: 10min stop at 20ft / 6m, very slow ascent rate from there 10ft/3m per min. I think I understand you as saying ideally do a deep safety stop if you're going to 18m or below, >=60ft, in which case do it at half your depth, so in this case it would be at 9m/30ft. That's cool & thanks for your input which I found very helpful.

Hi Helen:

You are welcome. You are an astute student and should make for a fine diver. The study for human studies on deep stops in recreational diving should be out soon, but a summarized report was published in DAN's Alert Diver early this year.

Saturation - thanks for the link to the exercise/ascent rate rat paper. It's really great that research seems to be taking off in this area and that there are things to quote at people! I don't want to come across as the pushy one on my course, but to be honest I've not been impressed and we're talking about serious issues & research. Re. my symptoms - not sure how an ear infection can relate to shoulder pain??

The paper I linked was not supposed to be authoritative, just one of many, if you click the Medline 'related articles' link it should take you to more current and human studies ... across a spectra of different hypothesis being tested but related to ascent rates.

As for shoulder pain and ear pain etc., I jumped the gun on that but essentially if you are a new diver, most divers get pains in their shoulders because of wearing the tanks for the first time ... over 90% of divers develop ear issues ... some of which can cause a 'dizzy' sensation and lead to vomiting. They are common reasons, not necessarily yours, but given a probability based diagnosis, the more common are apt to #1 on a list.

If you were injured enough to require a physician, your symptoms would not have subsided without professional help. That you didn't mention more of it suggests that after the episode, it waned over time ... thus unlikely to be DCI.

Does anyone think the PADI o/w course should be updated soon? I'd like to know how often their trainers have to be updated with the latest research, or if they just have to know the current syllabus.

If you are doing basic open water, PADI tends to limit knowledge to the absolute essentials and not make the course intimidating to those new to the water. Thereafter, in advanced OW, more material is given but I'm so removed from the curricula I leave a better answer to our good instructors herein. I do recall however, that 30fpm was hinted as a better idea when I took BOW ... my old computer was GREEN in ascent rates at 30fpm and RED at 60fpm. Nowadays, computers are RED when ascents are over 30fpm.

 

[Dr Deco]

Hello Helen:

Filtering Down

In practice, it does take some time before laboratory information is transferred to the realm of most individuals who would use that information. In truth, time reveals that some of it was not as useful as it first appeared, also.

To pass this info along, and to make interpretations of it for recreational divers, is the reason that I started this “Ask Dr Dec” forum in 2000. From the many comments, I know that it is helping. It would be better if more divers were aware of Scuba Board.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :1book:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[northcoast_diver]

Hi all,

Having spent a few days reading this board, I'm shocked at how little of this wisdom and research has filtered down to training. I'm currently on a PADI o/w course and there was no mention of
(a) the role of exercise, either before or after diving, or gentle (beneficial) vs. vigorous (harmful) post-diving.
(b) the slow-ascent curve (slower nearer the surface)
(c) the fact that dive tables are essentially PROBABILISTIC.
All of these seem important, given the knowledgable posters on this board.....

Helen

I am not a PADI instructor, so I cannot speak for them. But you may want to remember that Mr. Cronin of PADI recently passed away, and therefore right now the organization is probably more focused on succession, than on enhancing their basic open water procedures. They have also recently poured a lot of energy into their tech-rec diving program, and that is where their energy went.

The other agencies, like NAUI SSI and YMCA have always been totally focused on their recreational (non-tech-rec) program. And NAUI has Dr. BRW, who is the source of most of the new modern thinking, although credit also belongs to Jarrod Jablonski of GUE as well in the recreational area and cave diving, and to others (like Gary Gentile for wreck diving, and Curt Bowen for sidemount rigs) as well.

NAUI has officially begun to teach egression by halves, for every dive. It has only been official over the past year or so, and published in their instructor magazine. The concept has been developing over the past 5 to 10 years and comes from technical mixed-gas diving.

Some of the other ideas, such as restricting exercise before and after diving, come from technical mixed-gas diving as well.

Diving has changed over the past 50 years since the first training agencies were organized. And it continues to change, slowly.

Doc Saturation and Doc Deco keep us all honest as well. Welcome to scuba and to ScubaBoard!

 

[GreenDiverDown]

(The reason I'm concerned is that we did 4 padi modules at the bottom of a pool in a row, with several ascents but no surface interval to speak of. This followed fairly vigourous exercise (ie plenty of equipment hefts) and was followed by the same. I'm well aware that the likelihood of DCI is remote at this depth (4m) but about 2hrs later, there was slow onset of shoulder pain, until I felt like I had been hit in my shoulder by a sock full of lead weights. Pain increased to level of nausea & near-retching by 6hrs later. Was not a muscle issue - at least, it certainly didn't appear to be as it did not increase on any particular movements, and there was no sudden onset as there is if you pull a muscle or it goes into spasm, and there was no muscle tenderness at any time. Also, I was very thirsty due to being in a rush to get there on time and not taking any water since I woke up (oops).
Helen

Hi Helen,

I realize that this does not answer the question that you asked but ...

I think you should go see your doctor. The symptoms that you described really shouldn't be blown off.

How old are you? Do you smoke? Do you have hypertension, diabetes, or high choelesterol? Do you have a family history of heart disease? Do you exercise regularly?

I don't mean for you to answer any of these questions here on scubaboard but you can probably see what I'm suggesting. Pain to the point of "near-retching" is not something that one should experience after a pool session.

Go see your doctor....before your next pool session...or any other strenuous activity.

 

[Mrs Mares]

Hi all,

Having spent a few days reading this board, I'm shocked at how little of this wisdom and research has filtered down to training. I'm currently on a PADI o/w course and there was no mention of
(a) the role of exercise, either before or after diving, or gentle (beneficial) vs. vigorous (harmful) post-diving.
(b) the slow-ascent curve (slower nearer the surface)
(c) the fact that dive tables are essentially PROBABILISTIC.
All of these seem important, given the knowledgable posters on this board.

We have our open water dives (10m & 18m I believe) coming up soon. I would like to know what you believe is the perfect ascent from these depths. (Current PADI wisdom is a safety stop at 5m/16ft and ascending at an 18m/60ft per minute rate all the way.) I have noticed that some of you put in more than one safety stop, even for relatively shallow dives. Would your perfect ascent profile include this, even at an 18m or 10m dive?


(The reason I'm concerned is that we did 4 padi modules at the bottom of a pool in a row, with several ascents but no surface interval to speak of. This followed fairly vigourous exercise (ie plenty of equipment hefts) and was followed by the same. I'm well aware that the likelihood of DCI is remote at this depth (4m) but about 2hrs later, there was slow onset of shoulder pain, until I felt like I had been hit in my shoulder by a sock full of lead weights. Pain increased to level of nausea & near-retching by 6hrs later. Was not a muscle issue - at least, it certainly didn't appear to be as it did not increase on any particular movements, and there was no sudden onset as there is if you pull a muscle or it goes into spasm, and there was no muscle tenderness at any time. Also, I was very thirsty due to being in a rush to get there on time and not taking any water since I woke up (oops).

Ok, I know it is still unlikely, but whether it was a bend or not I'd still be interested in your individual views on the perfect ascent from 10m and 18m (?33ft & 60ft).

I would like to practise good ascents from the start of my diving history - and maybe discuss alternative thinking with my PADI ow instructor & group....

Helen

You don't state what part of the world you come from, but here in Britain our Padi O/W Manual clearly covered the 3 points you raised. :11: