How to know when to ascend before SWB

[dom12]

I fully understand that all free divers are different and have different lung capacities/ bottom times.
But how do you tell when your body has gone through too many contractions and is finally signalling for an ascent.

From training, i have found that contractions come later and later as my body adapts.
From this is know that my body is better at dealing with the CO2 and is using less O2, but how do i know when its too many contractions and my O2 levels are actually low or at their lowest before SWB.

This is very important to me as i am now training for better bottom times at my usual depths for spearfishing techniques.

I dive with a buddy, but still don't want to experience a black out. lets say if i dive to 18m and stay there for 1:30, within that time lets say i go through 5 contractions in a row and they subside again. Do i come up at the next contraction even if i feel good (which is what i have been doing) or can i still stay longer until i get a different feeling..what feeling?

 

[Bill McIntyre]

If there was a reliable "feeling" then it would be widely known and we wouldn't have so many SWB deaths.

I suggest that you buy a Freedive Recovery Vest.

http://oceanicss.com/frv/

 

[dom12]

Thanks for the link for the vest, will also check videos of them as still don't believe they are that safe ( e.g float up but face down).

I know there's no distinct feeling to go through. But is there a general rule as to how many contractions to go through, come up at the 1st set? Come up at the 2nd set? Etc... Ge

 

[Bill McIntyre]

I have the vest. I guarantee that it leaves you floating face up, looking at the sky. If you leave your snorkel in your mouth, the tip of the snorkel is even out of the water. Its very difficult to roll over even if you try. Click on the link to the training chapters and see videos of it in action.

As to the question- I don't think there is a general rule. It varies from person to person, and from time to time in the same person.

 

[esom]

Yes. So it´s personal. The important (personal) question then becomes "how to find out?" This question is crucial for freedivers of all kinds, i think.

 

[Bill McIntyre]

I think we're going in circles. I hope some of the real experts will join this discussion, but its my impression that it not only varies from person to person, but from one day (or hour) to another in the same person. There is no reliable warning, so the question is what to do about that uncertainty.

One option is to always have a buddy, but he should be better than you are so that he can handle recovering you even though he is not at his best because he is excited and maybe not able to breath up properly. But of course if he is better than you are, then you are worse than he is, so you aren't the perfect buddy for him. The teenage son of Terry Mass, the inventor of the FRV, died off Kona while his buddy could see him from the surface, but the buddy couldn't reach him. I don't think that its a coincidence that Terry developed this vest. Also, Terry is a word record holding spear fisherman and a former member of the National Spearfishing Team. If he thinks he needs to wear this vest, maybe I do too.

Another option is to avoid ever pushing your limits. Your posts give the impression that you want to push the edge. If you push the edge all the time, you may step over the edge. Is the possible reward- maybe a fish or two more- worth the risk? Ask your wife or loved ones what they think. I've been diving for over 60 years and I'm not very good at it, but I always try to leave myself a comfortable margin. So far its working for me. In all that time I've never felt a contraction, even on a couple of dives when I definitely exceeded my limits, felt my legs burning, and then saw stars after I hit the surface. If I don't feel contractions, what am I supposed to use as a warning?

And of course a third option is to buy a FRV, even if you always dive with a buddy and always try to stay within your limits.

 

[dom12]

Yes i fully understand what you mean Bill.

I get contractions one minute or sometimes 1:20 into the dive and they come back around 2 minutes into the dive if i am doing my max of 3:20.
I still feel good after my 1st and second sets of contractions, but i want to better my time and depth.
So it is worrying to me that i can't tell how far to push it… is my 3rd set a definite sign of really needing air and my limit or is it further? Do i really only know by pushing it and then seeing if i black out or do i just not go that far and never find out. I mean i can do dry statics and see if i pass the 3rd set and see how many more come after..but its not the same as in the water and at depth.

As most know contractions will come earlier when diving than dry statics, as co2 builds up quicker and although still the same lung full of air, O2 is used up quicker also.. Thats why i am so keen to see what experience divers say on what goes on in their mind and body when they feel and know they should turn around and surface. As i am only going off of fear of blacking out to discontinue going deeper. Are the signs when the bodies contractions get extremely violent etc..?

 

[Bill McIntyre]

http://forums.deeperblue.com/threads/video-of-a-shallow-water-blackout-by-a-spear-fisherman.101776/

A quote from the victim

And remember, every day id vastly different. Be aware of your overall health. Did you get good sleep? Big leg workout or run the day before? These things can make your body operate differently. And the scary thing is your brain/mind does not bear these factors. It tends to be conditioned to know what you "normally do." In diving, there is no such thing as a "normal" day. Consider all factors, and be safe so you can have fun again tomorrow

 

[cdavis]

BO is a funny thing. I've seen a diver BO on a dive well withing his capacity. He wasn't uncomfortable, had done similar dives a zillion times, no warning at all. I've seen two others where the diver was clearly exceeding capacity. I've exceeded my capacity far too many times and never had a BO.

There is no general rule or reliable pattern. All you can do is get to know your capacity, don't exceed it, have a tight buddy system and a FRV is still a good idea.

On another note, I own an FRV and, if it goes off, you are going to the surface, fast, face up. You don't have any choice. One of the best quality pieces of equipment I've ever seen.

 

[esom]

Are the signs when the bodies contractions get extremely violent etc..?

The idea of "body reactions" is often misleading, i think this is partly why your question is rejected repeatedly.

This idea can seperate thought, and feel and body, although no human being can describe the borders, without easily being disproven (for example by a freediver). Interestingly even if one tried he or she had to integrate feel and thought and body to do so.

Thanks for the great video and qoute, Bill

 

[growingupninja]

A spearfishing environment is a horrible place to experiment with limits or diving to failure (BO or samba) because it puts both you and other divers at serious risk. If you are really interested in exploring all that, work in a controlled environment with safety divers--dry, pool, dry, competition, line diving. An O2 sat meter and HR meter can be very useful, but you have to do a lot of self experimentation, research, and regular training to get anything out of biometrics. My experience is that contractions are a very, very poor indicator of remaining O2; typically they just mean dive response is kicking in, which can be triggered by a variety of factors.

Long days of spearing also fatigue the body differently than other types of apnea. By the end of the day your metabolism can shift and the body can be in strong ketosis. Perception of fatigue, CO2 generation, and O2 consumption all change in ways that increase comfort but put you closer to the edge.