Freediving myth #1 The dive response

Hey Connor - I could come down and throw M80s in the water for you if you like.

'Dive response' seems a reasonable name to summarize the particular set of adaptations which arise in response to freediving.

The response being reduced over time makes sense insofar as it is a stress reaction. It seems logical to conclude that the particular set of responses associate with stress, danger, fight or flight etc. would decline as you become more accustomed to and comfortable with the stimuli that evoke them. At the same time it also makes sense that you would continue to become more adapted to the activity - as in 'better at it'. So a tentative hypothesis might be we get an initial boost from the stress mechanisms - but that these decline over time and are replaced by intentional skill and more specific and specialized adaptations?

We could take martial arts as an example - there are schools of practicethat base themselves on the fight or flight response - using diet, herbs and all manner of stimuli to increase speed, reflexes etc. etc. Getting themselves as 'whipped up' as humanly possible in order to exploit the body's stress responses and instinctual aggression.

Yet other schools cultivate deep relaxation toward the ideal of no or very little change even in pulse during what most of us would regard as an acutely stressful interaction. Advanced practitioners of this demonstrate time as subjective.

Some schools go so far as to view these approaches as part of a triune evolutionary structure; animal, human and spiritual - with the development of a martial artist being a progression through them. So we have both the 'horizontal' view - wherein these are viewed as discreet entities with differing approaches - and a 'vertical view' wherein they are seen as strata in a progression.

Likewise in Yoga we have the essential model of a journey from gross to subtle. Why not so with freediving? Who's to say we don't come to points in our practice where we experience fundamental shifts in the way we adapt (law of octaves?) - and must adjust our methodologies accordingly if we wish to continue to progress - rather than labor under a set of rules that no longer fully apply.

I'm of the opinion the aquatic ape theory is unneeded (as well as unfounded). Our bodies and minds are generally adaptable to various activities that are likely to arise and, when we engage those activities consistently and in a reasonable way (not pushing ourselves to destruction) we get better at them. So much the better when we use understanding to optimize our training.

Water has been around for awhile - its not silly to recognize the fact that humans have developed some mechanisms for dealing with it - as in babies holding their breath when you plop 'em in - etc. That don't mean we're some kinda riped up seamonkeys.

thanks Fondueset, you say it so much more clearly than I do!

thats basically what i was trying to say that over time the stress is less the the dive response isnt so hard.

well i remember seb Murat saying he was laways trying to find new ways of stresssing himself more before the dive to kick his DR (or what ever we are calling it ) in more.

DD

The Dive Response is compiled of:

1. Blood shift, caused by:
a) peripheral vasoconstriction (sympathetic nervous system)
- due to cold (remember water conducts 20 x faster than air, so 24ºC water is like 10ºC air)
- due to hypercapnia (normally around the first contraction or sensation of urge to breathe)
b) haemocompensation (mechanical) - occurs only when lung volume drops below RV (around 20-30m into the dive).
(so effectively there is a shunting from the outside [vasonconstriction] during any apnea or cold-water immersion, and also a sucking from inside the lungs [haemocompensation] in deep dives)

2. Central hypertension: a mechanical result of central blood pooling (bloodshift), which causes bradycardia - the sympathetic nervous system's response in order to maintain constant cardiac output.

3. Splenic contraction (sympathetic nervous system)
- due to hypercapnia
- due to stress or anticipation of apnea (recent Swedish research suggests)

So it doesn't look like there is any nervous system response to actual diving (i.e. to the pressure). The only response is mechanical (haemocompensation) - everything else is determined by cold, CO2 or stress, all factors that don't depend on diving deep.
I don't think the mechanical reaction qualifies as an evolutionary adaptation: our lungs have adapted for life on land, and it just so happens that there is enough elasticity in the pulmonary blood vessels to allow a certain degree of pooling, but this is hardly efficient when you consider the rigid airways, sealed air chambers and the barotraumas that plague them.

This makes me think about the idea of 'relaxing into tension'.

One aspect of training being the elimination of static, mechanical tensions that impede the body's ability to cleanly and rapidly engage the above responses. A positive example being working with bandhas - etc. to increases the elasticity of the lungs, diaphragm and ribcage.

Over time it gets easier to let the body fall into alignment, as it were, with conditions - hence easier and more economical.

Same of the mind.

When I first started approaching RV I was stopped by anxiety. The sensation in the center of the chest is very similar the physical part of an anxiety attack. For me it took an understanding of what was going on and diving in a very conducive and safe environment to fall through this point and let the psychological patterns associated with the sensation evaporate.

Muscles are muscles and Sebastian is Sebastian.

Old words of wisdom from the Jungle.

Very interesting thread, it went from April Fools to some serious discussion of stuff that isn't very well understood.

I've been dutifully training my "dive response" for years, working on longer times in serial frc diving. Something is sure working, but it doesn't appear to be blood shift/bradycardia. I've tried the no warm up approach. Sure enough I can get a strong blood shift and bradycardia, but it feels HORRIBLE. No way do I want to dive like that. Max dives aren't my thing anyway. If you don't start getting blood shift until either co2 gets high or you get near RV, then what I thought I understood about the theoretical basis of frc diving doesn't make much sense. Since frc obviously works, what is going on? Are we chasing the wrong thing? If we get there anyway, what are we really doing right, in either frc or full lung. Bottom line: should serial divers even think about "dive response," or should we focus our attention on something else.

Anybody what to take a crack at this?

Connor

from an amature!

i think that dive response and dive comfort get confuses alot, most of the sesations associated with the dive response in my training are not enjoyable as such but we learn to search for these changes and in that they become beneficial and wanted but never enjoyable.

FRC diving amplifies pressure compared to inhale diving so reachinjf RV comes sooner and this will help with blood shift coming on earlier.

however the relaxed state accociated with exhale diving i think puts the body and more importantly the MIND in a sgtate that is more conducive to diving than inhale or packing (again a learned response moren than anything else)

i'd say that most serial "recreational divers" are better off looking for and training towards comfort in the water and particular aspects of the "Dive response"... or what ever we are calling it. many aspects of the response still come simply from being in the water itself so these are still achievable for recreeational diving, but i dont believe that major bloodshift need be sought.

many spearfishers have an average couple of dives then feel good and bottom times/depths increase after this, i think this is more to do with die comfort than anything else, because spleen contraction will only happen once and blood shift will not be a strong on repetitive dives, so there diving is moe explained by comfort and the other smaller aspects of blood shift.

your right this is a very interesting subject that hasnt been cemented in training or any other techkings yet, proably because we are not 100% sure exactly what causes what and how it works exactly.

DD

There is a relatively new study comparing the diving response at freedivers and non-divers. It may be of an interest:

Circulatory effects of apnoea in elite breath-hold... [Acta Physiol (Oxf). 2009] - PubMed result

AIM: Voluntary apnoea induces several physiological adaptations, including bradycardia, arterial hypertension and redistribution of regional blood flows. Elite breath-hold divers (BHDs) are able to maintain very long apnoea, inducing severe hypoxaemia without brain injury or black-out. It has thus been hypothesized that they develop protection mechanisms against hypoxia, as well as a decrease in overall oxygen uptake. METHODS: To test this hypothesis, the apnoea response was studied in BHDs and non-divers (NDs) during static and dynamic apnoeas (SA, DA). Heart rate, arterial oxygen saturation (SaO(2)), and popliteal artery blood flow were recorded to investigate the oxygen-conserving effect of apnoea response, and the internal carotid artery blood flow was used to examine the mechanisms of cerebral protection. RESULTS: The bradycardia and peripheral vasoconstriction were accentuated in BHDs compared with NDs (P < 0.01), in association with a smaller SaO(2) decrease (-2.7% vs. -4.9% during SA, P < 0.01 and -6% vs. -11.3% during DA, P < 0.01). Greater increase in carotid artery blood flow was also measured during apnoea in BHDs than in controls. CONCLUSION: These results confirm that elite divers present a potentiation of the well-known apnoea response in both SA and DA conditions. This response is associated with higher brain perfusion which may partly explain the high levels of world apnoea records.

Click to expand...

It occurs to me that there may be a lot of physiological things going on in answer to connor's question. To really answer "how to train" it may be necessary to really delve into biochemistry. It seems that the dive reflex is less intense as the diver increases in ability. There are so many possible hormone changes that may control or assist this that it boggles the mind. Just one of the options is genetics. The stress from training may change the location of, or remove, methyl-groups that are used to block off unused genes, so we may be producing hormones that change the way cells respond to the stress. Even within this we could ask whether the additional hormones are assisting with controlling free radicals or assisting with the transfer of fuel and oxygen into the mitochondria, or removing metabolic wastes, or ???. And this is only one example of where what may be going on. As training continues aditional changes may occur, causing complex results that boggle the mind.
Short of spending a lifetime or two doing the biochemistry (instead of freediving) my guess is that the best we can do is to contribute to these threads and interact over what does and what doesn't work, and make guesses and extravagant claims about which is the best technique.
Howard

Maybe the alleged DR is, in fact, a somewhat more generic stress response.
As we train properly we naturally extend the envelope - the edge of which marks the point where it engages.

Where's Sebastian Murat when you need him? :t

So far, we are mostly talking about physical reactions relating to DR. Physical reactions are easier to quantify, they're measurable, and somewhat predictable.

Enter the harder to quantify, but IMO just as vital to successful dives:

How about mental states and psychological adaptations over time? It's harder to hook your brain up to a pulse oximeter or HR monitor.

For example, does your attitude and pre-dive feelings affect your performance? Beyond just being stressed or nervous, I mean are you feeling positively motivated and excited about doing the dive? Can't wait to do it? Or, are you diving because you don't really WANT to, but you MUST, because it's a comp or a record performance or you have something to prove.

Can you weave FUN into a maximum dive?

Mental states and attitudes could explain why there is a gap between training and comp performances and why some people do well at comps and others don't. Please don't tell me this has anything to do with the body.

Let's tap the mind folks.

Maybe I got a strange body.

With normal inhale dives doing dynamics I don't get (noticeable) vasoconstriction, even when I swim to samba.

I used to have a decent amount of vasoconstriction during static, and when I was reaching the 6' level I programmed my body in such way vasoconstriction started before the max static dive.

Nowadays I get the very distinct feeling of vasoconstriction when after surfacing from negative dives to the 3m deep pool end.

Also I get it during dynamics and when diving FRC or less.

You can feel strong vasoconstriction like a tightening in the limbs, and most profoundly when you surface and breath you'll notice the relaxation and your blood flowing back from the core to the limbs. - Very nice feeling for me

My question revolves around my 'poor' dynamics.
I seem to get hardly any vasoconstriction going. I would like to change this into having plenty after 50m, so my muscles go anaerobic and my heart and brain get to use the rest of the O2.

What is it that triggers vasoconstriction?

Any insights / tips from you guys would be very welcome!

Kars i think if you turn the first 50m into a "static" so VERY slow with little effort that your "DR" will kick in more effectivly and you will find that the vasoconstriction will be more complete, i know a couple of higher end divers doing this and it works well, i find for myself that it also works however i struggle on the mentle side when taking this approch.

Demasoni i also think that there is a STRONG link between mentle sate and maximum performance (for me anyway) i always try to weave some "FUN" or enjoyment into every dive i do including max, otherwise i just dont do them!

i really believe that if the mind is prepared for the dive and you really believe that you are ready to do that dive then basically you have already done it.

as long as your physical training and preperation are strong then once the mental side is done then the dive is in the bag.

again i can think of a couple of divers that spend the day before the dive and the orning leading up to the dive stressing and going through all the difficult mental emotions which i generally get DURING the dive. but when they get in the water, they are as relaxed as cam be and just swim the swim they have planned and visualised. it islike they have dealt with all the mental challanges before ever getting in the water. so in his mind the hard part is done and now all he has to do is swim.

its very interesting and ALWAYS seems to work.... still cant quite get my head around it though.

my best dives both for max attempts and enjoyment are when i am in a positive head space and really WANT to do the dive, the days when i dont fel well and dont really want to go to training i may do a good number but the dive feels terrible.

DD