• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

How does dynamic apnea measure up to actually going down?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.


New Member
Jan 16, 2002
I was hanging out at a buddies condo and he happened to have an olympic pool. So I gave it a shot thinking I wouldnt even be able to cross it ( approx 100 ) well to my surprise I cross it the first time and actually did a there and back = 200ft. This was BARE foot and frog swimming. I figure I could do at 300 with my cressi's.

So with that in mind, what sort of judgment can I expect for going down? I mean if I can do 300 ft dynamic, what can I do with a free fall dive with a weight belt and my cressi's? I sure know I cant do 300 ft!!!!!!!!!!!!!!!!!!!

So whats a good scale to go by?????
Hi Mark,

Eric Fattah has given a formular once.

For those interested, I developed a formula to convert dynamic apnea to constant weight:
DYNAMIC = (4/3)*CW + 22

i.e. 60m CW->
DYN = (4/3)*60 + 22 = 102m dynamic (this formula does not take into account that last TURN at 100m!)

This formula is not 100% accurate; it depends on how thick your wetsuit is, how much weight you wear, what kind of fins, and how easy you can equalize, psychology etc.., but for good conditions c.w. it holds pretty close for most people.

Please don't ask how I got it; it has a lot to do with physics/gravity/metabolic rate, as well as fitting data to experience....

Eric Fattah
BC, Canada

Perhaps this can answer your question.


Without knowing the formula I always felt like a 75m dynamic feels like a 40m CW dive if I compare it.... and when I now use 40m in the formula it gives me 75.333m dynamic.:)

The truth is probably somewhere around this.
Rule of thumb

I have usually halved my dynamic and found that it was roughly equal to my CW depth.

But my CW has always lead my dynamic by some. I suppose thats because i reach depth in total comfort so going deeper is usually a matter of deciding to do so. On the way back you have no choice but to reach the surface.
With dynamic you can chicken out anytime and often one does.

With dynamic you can chicken out anytime and often one does.
or the opposite is true.
I heard that dynamic is the catagory that has the most b/o's and samba's since people consider it much safer and tend to go more easly above their limits.
I do agree though that CW is much more comfertable which really helps to get more distance done.

I think CW is far more dangerous, like skin said I too often ckicken out if I do a dynamic but with constant I often keep going to I get to the bottom and have little idea of the depth other than my lungs are crushed, then you cant chicken out :naughty

that's right

Right, Peter!
Same for me - 75 m. dynamic vs. 40 m. CW
CW is feeling more comfortable than pool exc., esp. at the bottom, right before the ascend, even want to prolong the moment before starting to struggle on the way up.
Who is 'ckicken out' how?
I do it in 25m intervals only, does anybody break the pool length?
DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


ISSN 1469-865X | Copyright © 1996 - 2024 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Ocean Advocacy and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.