Freediving after scuba diving?

[Sickboy]

Hello all. I have a question regarding the dangers of freediving after scuba diving (the same day, perhaps after multiple dives).

I posted this question on rec.scuba some time ago, and we basically concluded that there is very little danger in increasing the nitrogen in your blood by freediving after scuba, but that the constant (rapid) decents and ascents would cause the nitrogen already in your blood to compress, pass out of the bloodstream, then re-expand and cause the bends.

This sounds logical to me, but I was wondering if anybody here has a different, plausible opinion. Also would there be a risk if you freedive after only 1 scuba dive? I know Decompression Sickness (DCS) is still largely a mystery, so it would be difficult to quantify the increasing risk with more scuba dives. Do any of you ever freedive after scuba?

I'm asking mainly because I am going on a trip to Redang in Malaysia in a couple of weeks with some friends for scuba diving. I have done some research and the dive profiles seem to max out at 20m and current is moderate. If this is the case, I would be keen to freedive while the others scuba. Chances are that I will end up scubadiving, because I would not be able to stay down at 15m for longer that 1min at a time. But I would like to freedive between scuba dives to improve my freediving.

Would it be reasonably safe to freedive between our 2 scuba dives a day? I know nobody will be able to give me a definate answer, but any advice wouldbe helpful.

Thanks in advance.
Terry

 

[Cliff Etzel]

Don't Mix Scuba and Freediving

If you understand anything about diving physiology and physics, you would realize that your chances for getting DCS will increase dramatically. Mixing freediving and scuba is a BIG NO NO!

Unless of course you want to get DCS, then please do - I may sound harsh in this response, but I am a certified PADI Rescue diver, so I have a basic understanding of what will occur if you choose to do this.

But this is your choice - this was one of the biggest reasons why I choose not to tank dive any longer - I just did not want the chances of DCS occuring any more than neccessary.

Bottom line - it is not safe to mix the two disciplines.

 

[freediver48]

Hi,

This really is an interesting question, and clearly freediving during your surface interval is for sure a bad idea. I wonder how a freedive/scuba computer would respond to this question. It would be interesting to create some simulations, given different diving scenarios. I'm sure we would get some very different answers given depth by time variations.

Thanks for the question,

Freediver48

 

[Erik]

DCS

Hi all, the common concensus is that you should wait until either your computer clears, or your tables clear you of nitrogen. Because DCS science falls somewhere between science and art, there is always the risk, even within the parameters of tables and computers.
Since I started freediving 3 years ago, I've use compressed air less and less. For the last 2 years, I've only used scuba twice for recreational diving, and that was for deep wrecks. I still use compressed air a lot, but only for commercial work and teaching scuba. My point is that I have become more scared of getting hit, the more I don't use scuba. I have 4 friends who have been hit while "inside" their computers,no deco, on liveaboard trips. Freediving is so much more pure and gentle, but I do remember the attraction to compressed gas diving and don't look down at anyone who likes it.
That said, the risk of DCS is too high when freediving is combined with scuba for me. The thought of spending the rest of my life in a wheelchair horrifies me to no end. No more diving, no running, no biking, no freedom, no making love to my wife. Does she deserve to have to take care of me for the rest of her life? She would do it, but I won't do that to her, or myself.
When I started fdiving, I used a scuba computer....it hated me, and actually started to load nitrogen on the graph, as a way to penalize me for the rapid ascents. Not that I cared about that; I just wanted a guage, but combining scuba and freediving profiles would not make any computer happy I think. I don't know what a Stinger or Mosquito would do in this situation, since you can go in and out of freedive mode. I wont be the one to strap one on and see.
Freediver mag has a very good article on this topic in the latest issue...very scientific, and the article boils down to "No Way".
Sickboy, I consider you a friend, if a cyber-friend. I would not like to read a post from you saying that you will have to live up to your Cyber-name for the rest of your life. The world is very small, maybe we might have an opportunity to dive together if you don't injure yourself? I'm being dramatic because the consequences of toying with the "art" of decompression theory can be dramatic. Have scuba days, and have freedive days on your trip. Drink lots of fluids, and enjoy the looks of disbelief from the scuba people when you tell them that you are happy to spend some days only freediving.
Sincerely,
Erik Young

 

[Cliff Etzel]

Re: DCS

Erik - Eloquently stated.

Originally posted by Erik
Hi all, the common concensus is that you should wait until either your computer clears, or your tables clear you of nitrogen. Because DCS science falls somewhere between science and art, there is always the risk, even within the parameters of tables and computers.
Since I started freediving 3 years ago, I've use compressed air less and less. For the last 2 years, I've only used scuba twice for recreational diving, and that was for deep wrecks. I still use compressed air a lot, but only for commercial work and teaching scuba. My point is that I have become more scared of getting hit, the more I don't use scuba. I have 4 friends who have been hit while "inside" their computers,no deco, on liveaboard trips. Freediving is so much more pure and gentle, but I do remember the attraction to compressed gas diving and don't look down at anyone who likes it.
That said, the risk of DCS is too high when freediving is combined with scuba for me. The thought of spending the rest of my life in a wheelchair horrifies me to no end. No more diving, no running, no biking, no freedom, no making love to my wife. Does she deserve to have to take care of me for the rest of her life? She would do it, but I won't do that to her, or myself.
When I started fdiving, I used a scuba computer....it hated me, and actually started to load nitrogen on the graph, as a way to penalize me for the rapid ascents. Not that I cared about that; I just wanted a guage, but combining scuba and freediving profiles would not make any computer happy I think. I don't know what a Stinger or Mosquito would do in this situation, since you can go in and out of freedive mode. I wont be the one to strap one on and see.
Freediver mag has a very good article on this topic in the latest issue...very scientific, and the article boils down to "No Way".
Sickboy, I consider you a friend, if a cyber-friend. I would not like to read a post from you saying that you will have to live up to your Cyber-name for the rest of your life. The world is very small, maybe we might have an opportunity to dive together if you don't injure yourself? I'm being dramatic because the consequences of toying with the "art" of decompression theory can be dramatic. Have scuba days, and have freedive days on your trip. Drink lots of fluids, and enjoy the looks of disbelief from the scuba people when you tell them that you are happy to spend some days only freediving.
Sincerely,
Erik Young

 

[Jon]

Freedive first, scuba later.
Don't forget that you can also get bent freediving alone. THere are dive tables for freediving. They don't have deco stops built into them, but the do have surface interval requiremnts. The deeper you go, the longer you nedd to stay on the surface between dives. 2:1 is a good rule of thumb to start with. A 1 minute freedive menas a 2 minute surface interval.
If you want to snorkel after diving you should be OK. Max depth should be less than 10'. If you are thinking aout pushing it you should know that freediving DCS is a type II neurological hit. THat means it is a lot nastier than a type I pain only hit.
Hope that htis helps.

Jon

 

[freediver48]

Hi,

This is what the Suunto Stinger manual says about the question.

"WARNING

Freediving after scuba diving is not recommended. It is recommended to avoid freediving for at least two hours and not exceed five meters (16 ft) after scuba diving depending on your diving activity. Suunto also recommends you to be trained in freediving technique and physiology before conducting breath holding dives. No dive computer can replace the need for proper dive training. Insufficient or improper training may cause diver to commit errors that may lead to serious injury or death." (p. 7)

Best wishes,

Freediver48

 

[Sickboy]

Thanks everyone for your useful input, and I appreciate your concern for my health. I guess I was hoping for someone to say "actually freediving after 1 scuba dive is OK", but in fact I have seen so many arguements against it (not only in this thread) that it would be insane to ignore.

For me it's a real shame because most of my trips to nice dive places are for scuba, and since I have never met any other freedivers on trips, my freediving just gets left behind.

What I'll do is try to freedive while my friends scubadive for the first day, and see how it goes. At worst I can scuba for the rest of the trip (5 days).

What has been everyone's experiences when going on a scuba boat and just freediving? I have a feeling the divemaster will not be very happy, and would be worried about liability issues, buddies, etc. Also if the first day is current diving, I would be reluctant to freedive. At worst I can just skip the first day of diving and just freedive at the reef infront of the resort.

Anyone have some advice about freediving with a bunch of bubble blowers? I guess the obvious would be not to dive too close, so that their racket doesn't scare the animals away from me. Also getting into the water first would be good, so that I can get the dive reflex going sooner and have almost an hours good freediving.

I would just love it if in the middle of the dive a giant manta or whale shark appears to check us out, but the scubans can't get to it in time cos they have to ascend slowly and their bubbles scare the poor beast away. The dream of the ultimate freedive continues!!

Dive deep...

Terry

 

[Jon]

I have always left most of my freediving until the last day. You really can't scuba on the last day if you are flying out, so freediving seems to be a good choice.
I have gone out with boat loads of scuba divers. I had to pay the same price, but I was allowed to drift along and freedive with them.

Jon

 

[freediver48]

Hi,

Jon has a good point, time to fly is a problem one the last day
of a trip, and is a good time to freedive.

I recieved the following from the Diver Alert Network (D.A.N.).

" In regards to snorkeling after diving, there are reported cases of divers experiencing DCS symptoms after doing surface dives while snorkeling to depths of 80 feet or more. There is no real evidence that this would cause you to be more susceptible to DCS because the amount of nitrogen taken up by the tissues is small. Breath hold diving DOES however; stop your surface interval time and nitrogen off-gassing. This effect is probably minimal, and provided surface interval times are appropriately extended, the risk of DCS is probably small. There is some concern also regarding vigorous exercise causing bubble formation and possibly causing DCS. There is simply not enough research or information available to make a clear cut, scientific statement concerning the safety of breath hold diving during a surface interval." FD48


"

 

[Angus]

The subtle effects

Dear Folks, I am throwing my two bits into this very fine discussion to talk about the more subtle effects. There is real potential for an accumulation of minor and for the most part transient "bubbles" to form in brain tissues if compression and gas build ups are not well managed that only start showing up over the course of years for the most part. This was first discovered in offshore oilrig divers who working at great depths for long periods. The neuropsychological damage ranged from mild memory and cognitive problems to severe Alzheimer's like problems and occassional Parkinsonial like tremors and gate disorders. These are permanent and untreatable. These types of cerebral traumas are asymptomatic but it is thought that they occur, at some level, in 100% of people who have DCS and also occur in at an unknown frequency in people who have no overt symptoms or signs DCS or any other problems. If they occur very infrequently you will probably go through your entire life and never know, nor will anyone else. It seems that they have an accumulative effect. At this time no knows how a person will be effected over the lifespan with these subclinical levels. Personally, I would be very careful about this.

Another area of concern I have in freediving is going to depth shortly after flying. Don't let the term "pressurized cabin" fool you into thinking that you were at sea level. They pressurize for somewhere below 10,000 feet - still way to high. I take at least a day after flying before I dive deep and I only freedive. I'll shallow dive but that's it. The reverse can also create problems. It is not a good idea to do intensive freediving and then jump on a plane. As the pressure goes down the gases in the system ..... something to do with conservation of volume. Just another one of those pesky unbreakable laws of physics.

Octo and I have been looking for freediving tables on this. We have heard completely unsubstantiate rumors of tables developed in Spain that are reputed to be topnotch. Anyone know of this, them, or the source? Thanks, Angus

 

[Angus]

Here's to you

I wanted to post this separetly. I think Terry's willingness to ask his question is spot on and very important. It not only shows the value of being willing to ask a question openly which can be hard to do because the very nature of such questions is a declaration of ignorance. In a sport mared by ego and guy mythologies; admitting ones level of ignorance can be very hard to do. So here's to you Terry and your willingness to put it out there and get what you need.

By asking his question, Terry not only saved himself from potential health risks, he most likely has helped others avoid similar fates when they read this thread. Just notice how many people have read this thread the short time it was posted, something like 130 - 140. I learned a lot from this discussion. This alone shows the value of this forum and the beneficial use of this technology. I am pleased to be part of a community that cares for its members as well as this one does. Thanks to all, Angus

 

[freediver48]

Hi Angus,

If there are surface interval tables from Spain, the picasso people will likely know about them, you might try Roger at Picasso America, also Pelizzari's site was listing a lot of course materials, that might include the tables. It to would be good to post the results of this search.

Freediver48

 

[Angus]

Good idea

Thanks FD48, Good idea. I'll keep you informed of what I find out. Angus

 

[Cliff Etzel]

But what's the real issue here?

:naughty I am going to take a perspective on this that I hope won't be taken the wrong way...

So what is the real issue here? Someone wants to mix freediving with tank diving. With the mountain of evidence (and the lack thereof) regarding DCS, why would you want to try and do both? Is your life worth risking for a sport? I am going to rant again and say do one or the other - you are risking not only your own life, but the lives of others who care about you should you become seriously injured or die due to making a bad judgement call.

Diving is a great sport - I love it. But I also know that it isn't my life. I have a wife of 20 years and 2 great kids that I would rather see grow older than be 6 feet under. I have read of many divers who left behind a wife and several children because they wanted to go that much deeper, or made a poor judgement call on their dive.

For me, it just isn't worth the potential of doing that kind of physical damage to myself and the emotional damage that my actions would inflict upon those whom I care about the most.

From a Certified PADI Rescue Divers POV - if I knew that someone had been tank diving and then went freediving and got bent or SWB - I wouldn't risk my life to rescue that person - you have all the information, and from a legality standpoint, according to PADI, I have the legal right not to risk my own life to save that persons.

Sound harsh - Probably, but I am not willing to become a casualty due to someone elses carelessness...

Happy Monday...

 

[Angus]

The bigger picture

Cliff, I appreciate you articulating the bigger picture. Our decisions effect more than ourselves and that needed to be factored into this. Your point about us needing to be responsible and that our level of responsibility can affect the level of how others may respond to us is also valuable. The number of times I have walked away from people doing foolish things - things they knew were foolish and dangerous is numerous. We are not the keeper of others and they have the right to screw up. They don't have the right to screw up and put others at risk however. Thanks, Angus

 

[Sickboy]

Cliff, thanks again for your reply, and for emphasising how horrible DCS is, not only for the sufferer, but also fro those around him/her. It is not something to mess around with.

I'm not trying to say you're wrong, I just want clarification on this subject. As far as I can see, it is ok to mix free diving with scuba IF you freedive BEFORE you scuba, and not after.

For recreational freedivers (say, max depth 100ft/30m), I cannot see nitrogen loading being that much of a problem as to increase the risk of DCS on later scuba dives, especially if you keep a safety margin from your NDLs. The nitrogen loading during the freediveing should be minimal. Perhaps if one spent more than 3 hours freediving, it would be harder to tell. In a way it's like drink driving. It's ok to drive and then drink, but not to drink and then drive.

Does this sound logical? Or am I missing something?

Regarding diving after a flight, I read somewhere that because aircraft cabins have a lower pressure than sea level during flights, your body will actually have a *lower* level of Nitrogen after the flight, which should resuce the risk fo underserved DCS if you follow a normal dive plan.

Of course this only relates to nitrogen loading and DCS. Are there any other problems that could arise from diving after having been in a low-pressure enviroment?

Terry

 

[Sickboy]

Angus, I'm glad you are finding this discussion useful. I am sure this is a very common occurence, mixing freediving (or snorkelling) with scuba, and yet I have searched the net and have found very little information directly related to it.

A friend of mine went to the Maldives for a scuba trip some time ago, and after a few days he displayed the symptoms of DCS, and had to go into the chamber for treatment. He made a full recovery fortunately, and is diving again now.

He was scuba diving with a computer, and was not doing decompression dives. But the problem was he was snorkelling between the scuba dives, and it turns out he was going pretty deep (around 20m I think), and so this seems to be the most likely cause of his DCS.

Soon after this I was in the Philippines to do my Advanced Open Water, and I specifically asked my instructor if there is a limit to how deep I should snorkel to if I have been scuba diving. He and another instructor in the room both replied "no, just make sure you have enough air to get back to the surface!".

On another scuba trip I was talking to an instructor and asked if he ever freedived. He said he loves it, but since he takes divers out every day, he can't freedive because he needs to give himself 24 hour to clear his scuba nitrogen.

On my most recent trip, I again asked the instructor if he freedived. He said he did and he had the fins and all. He said him and a few other instructors used to take a bunch of weight belts on a rope and drop down to 30m, then swim back up. He said he didn't do it anymore, and I asked if it was because he scuba dived every day. He said it wasn't because of that, it was because it was too tiring and he was too lazy.

It was this crazy inconsistency in peoples' attitudes that got me a bit worried, and got me looking into this matter. The fact that scuba instructors (of all people) could have such different perceptions on such a dangerous phenomenon just highlights the lack of knowledge we have about DCS, and even more so when mixing in freediving.

Obviously this risk pertains mainly to freedivers, since scuba divers who are not into freediving would only snorkel to depths that would not present much risk (less than 5m probably). That's why I'm glad we have this site and forum to discuss such matters, to try and prevent any accidents that may occur due to ignorance.

All the best,

Terry

 

[freediver48]

Hey Sickboy,

You are right on with your last statement, it sure is great to be able to communicate together. While we may not all agree on issues of risk management, and the like it sure is a great and illuminating hit, to visit Deeper Blue. By the way I p[osted your question on FDL and it got thumbes down, e.g.

"I would follow Terry Mass's recommendation. If these computers could follow and track your gas loading is not the issue. It really comes down to bubble physics. The worst thing you can do is freedive after scuba, whether it is deco diving or no-deco diving. To make a long story short, very short.

what happens is the micro bubbles that you get after any scuba dive grow as you come up, your lungs off gas these. unless you have a PFO the bubbles should stay on the veinous side and be eliminated by the lungs. if you compress them again, by diving, these growing bubbles and can compress and bypass the lungs and move over to the arterial side, this is bad. now as we
can not stay down very long we do not give our body time to handle this. as we start coming up these bubbles are growing on the wrong side of our lungs, the arterial side. so instead of using our lungs to filter them out we will now use things like our brain and other parts of our body we have grown to like. this can lead to a real bad hit.

This was the very short answer. If you need a longer one give a yell. If you must combine them, freedive before scuba only. Never between or after. But the best bet is to follow Terrys advise, do not combine them."

Alan Pelstring
S. Fl.

Will Rogers once said:
"If God didn't have a sense of humor, he wouldn't have made monkeys and some
people." Best wishes, FD48

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[Peter Sheard]

SCUBA and Freediving?!?

In a previous thread there was a brief reference to a relevant article in Freediver Magazine.

The complete reference follows:

Sheard, Peter (2001) A dangerous mix – SCUBA and freediving. Freediver 13: 18 - 19. ISSN 1466-089X

The article will be re-issued, by permission, on Deeper Blue sometime in September(?)

In the meantime, the DAN statement that there is not enough specific research to draw accurate conclusions is 'true' but slightly misleading -- there are some logical conclusions (from related research and basical physical processes) to be drawn that the combination is risky.

The risks lie not in added nitrogen but in 'migrating bubbles.'

Subscribe to Freediver Mag and find out more . . .

Pete