Exhale Diving for the "average" diver

[cdavis]

If you are going to be diving FRC, its really important to go to a minimal, shallow breath breathup. The extra C02 in your system kicks in dive reflex quicker, which is absolutely required for FRC to work. This should give you contractions early(but light at first). Getting them late and having a samba strongly suggests that your dive reflex was kicking in late rather than early, very likely some HV involved.

For me a 27 meter dive would look like this: very minimal shallow breathup, 2 half lung purges, inhale half way, surface dive, arm pull, two or three very soft kicks and sink from about 20 ft, slowly at first, 35 seconds to 27 meters, contractions start on the way down, pause until contractions are noticeable enough to be mildly uncomfortable, then come up. Hit the surface with a clear head and moderate to strong urge to breathe.

 

[VCO]

Wow
It was interesting to read a post stretching 10 years .

For those who practicing exhale diving . After doing it many years do yo have any updates on the techniques and training discussed in first few pages ?

Did you change anything or find any other useful tips ?


Second question is for a new starter having access to a 25 m pool with 1.6 m depth and sea with 5-6 m depth .
What kind of training routine do you recommend?

Thanks

 

[cdavis]

Still do and still think it is the best way to dive for serial diving in recreation depths.

Can't say I'm doing anything different than what's in the thread. One thing has changed, access to training pools, Both my depth and time have suffered from inability to train regularly. I've figured out how to maintain acceptable performace with dry exercises, but they are not as good as wet.

Reccommendations for a new diver:

Get a buddy and be very careful of squeeze. Exhale diving is different. Safer and longer bottom times once you know a bit about what you are doing, but tricky at first and fairly easy to screw up seriously.
Otherwise, follow the thread.

 

[Nathan Vinski]

Hopefully I can add a few things to this thread based of my recent experience.

In August 2017 I started primarily diving, although I had done quite a bit before, on FRC for probably similar reasons to Conor, early freefall, easy recreational diving with low risk of decompression illness, and also to play around with reduced narcosis in deeper dives as I was getting significantly narked quite early on inhale, around 50-55m although its noticeable at 35m. I've switched back to inhale 2 weeks ago.

In terms of approach what was previously mentioned here seems to be the best. Very minimal breathup to keep up the CO2, minimal warmups, and the first half of the dive should be as close to static as possible (STA+DYN in the pool, or Freefall + ascent in depth). with this approach, 45m CWT bi-fins is not an issue at all, as soon as I worked out a few kinks in my equalization, and I feel like 50-55 is possible without any hypoxia issues.

Recreational diving is actually more of a challenge for me as its harder to maintain the inactive descents as you sometimes want to cover distance while going down if the reef isn't vertical or there is current. The second issue with recreational diving is that my breath hold, on FRC, gets significantly worse the more dives I do in a session as my dive response gets weaker and weaker. I can start a session with 1-2 2:15+ dives and after that the safe limit goes down to 1:25(ish).

That being said, from a breath hold perspective, and assuming I'm weighted properly for both exhale and Inhale diving it is much easier and safer to perform the same dive on Inhale as it would be on Exhale. I can do 10 clean 30m recreational dives over 2 mins long on inhale but can only do that on exhale for 2 dives and surface clean, which shows that my inhale breath hold is much better than my exhale breath hold. On the line with hangs; 2:30 exhale dives to 20m are quite tough, but 3:15 inhale dives to 20m are very easy and end before the effort phase starts.

From a training perspective I wouldn't necessarily recommend FRC diving to train for inhale diving except for equalization work. on one hand it made inhale hangs feel really easy and 75m variable weight dives feel like nothing... the issues lie in loosing the ability to comfortably make effort to descend. I tried a 64m CWT (match my PB) and although the dive was clean it was super hard with loads of contractions and a trachea squeeze. I've had to take a huge step back and train 40m repeats without weights in in order to get used to finning down again. This took about 6 sessions to get used to and hopefully 60 won't feel so bad next time around.

A final issue is that exhale diving doesn't seem to be sustainable, after 3 weeks of consistent diving I started waking up extremely exhausted and needing more and more rest days, as soon as I switched back to inhale I felt normal again.

So while there are some benefits I would say that overall we aren't seals, and although our potential with Exhale diving is still very high, a human's best diving capabilities will come with full lungs.

 

[cdavis]

Fascinating stuff, Nathan, thanks.

You are doing much deeper diving than me, makes it a bit hard to compare, but there seems to be a major difference in dive reflex. Diving exhale, mine gets better and better as the dive session progresses, longer and longer dives, greater and greater depth. I would not be surprised if DR from the individual dive gets less over time( it should), but my blood shift is very cumulative, so that my effective DR becomes greater with time. Late in the session, I'll get tired,very quickly performance falls off(over one or two dives), and I just don't want to do it anymore. Changes in DR might be related, but I've always thought it was just getting tired.

EricF reported getting almost bloated with blood shift when doing full exhale dives, to the point of reducing his inhale. . Do you ever feel extremely blood shifted for a significant time after the dive session? When you surface do you breath deeply or try to keep it shallow? Do you think your results would be different if you were limiting your depth to 30 m or so?

 

[Nathan Vinski]

i never feel extremely bloated, even after a chain of RV dives doing 24,25,26,26,28. I didn't feel any type of heavy lungs or any other squeeze like symptoms. The only time I've ever felt heavy chested was after a lung squeeze (on inhale in cold water).

I always breath deeply after dives, inhale or exhale without any issues.

Most of my FRC sessions were limited to 25m on the line. I've also done wreck/reef diving in tenerife and dahab in the 15-30m range. My most promising results were in "deep" line diving, although 45 felt like 60 on inhale. In a recreational setting my worst dives are inhale (under weighted), then FRC are slightly better, but far beyond that (30-45 seconds longer active dives) is inhale with proper weighting, as on 30m dives I can set my neutral point at around 10m and still fin up easy.