Recovery breathing

[fishon]

Once you reach the surface, what is the ideal pattern of breathing to minimize the chance of blackout? For instance, I'm guessing you shouldn't come up and forcefully exhale and inhale deeply...

 

[Victor_]

My coach (Molchanova) proposes the following pattern: 1/2 exhale – inhale, 2/3 exhale – inhale, full exhale – inhale.

 

[strauss]

Why not inhale first if you can?

 

[Narsil]

If you're recovering from a breath hold, you'll generally need to exhale first - unless you've been doing a exhale / residual lung volume dive.

Victor_'s comments sound very sensible. Doing a hook breath to help with recovery is also a commonly used technique.

 

[lungfish]

The main issue isn't so much the inhale, 02 and breathing up, its reducing the C02 buildup and avoiding Nitrogen DCS. Returning from a dive you will have a large load of C02 so breathing it off is important. Additionally, one can oversaturate tissues with N over the course of several dives. A few hook breaths, or equal but somewhat accelerated or forceful inhale/exhales of equal duration before backing off to a more normal pattern to continue ventilating and normalizing gas balances is effective.

Of course, this leads into durations between dives and how long one should wait before diving again.

A standard rule is if the dive is above 25meters, then one should wait twice the duration of the previous dive before diving again. If it is below 25meters, then one should wait at least 8 minutes (See "The Attitude a Breath Hold Diver Should Take to Avoid Arterial Gas Embolism- a Study of 30 cases" Battle, John M. PhD, MD). Reasoning behind these durations involves normalizing gas imbalances before diving again with an emphasis on Nitrogen build up. Additional considerations include normalizing C02 balance before beginning breathing up....

Lungfish