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Negative Pressure Dives

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
Aug 9, 2002
Hey good people, me again. I was wondering, I do some ultra shallow negative pressure dives(3 feet) when im with my wife, but swimming alone. I go to a pool on most Thursdays with a depth of 12 feet, and I can dive that negative also. My questions are as follows:

1.) What am I doing down there? Just hitting the bottom and coming up, shooting for time or what?

2.) Is it cool to swim around on bottom, or should I just lie there?

3.) Is it a personal choice to exhale on the way down or exhale completely on the surface? Which do you think is best?

I can do 12 feet for about 30 seconds or so(give or take 10 to 15). Is this where I want to be on average? need help.

Hi TMcKee.
-What you are trying to achieve with the negative pressure dive is to bring your body into "the diving reflex" mode faster than having to do many dives to get that "I feel invinsible" feeling...It is the bottom time that you are going for not just bouncing and coming back...I do two negative pressure dives before my deep dives (never during pool training), one to 15m with a bottom time of 30-45 seconds total dive time between 1:45 and 2:00, then a second to 18m for the same time.

- It's not cool to swim around...sitting still is the only way you can concentrate on slowing down your pulse and bringing on the diving reflex...so sitting still is what you wanna do.

- it is never a good idea to exhale everything...general rule I follow is to exhale until you hit residual volume in your lungs (the point where you would have to make an effort to exhale)...exhaling on the way down makes it a bit easier...especially if you exhale slowly...

this technique is dangerous and should be approached with caution and a spotter / safety diver...YES even if you are just doing 12ft in the pool...
Pardon Me, but are Invard dives the same as Negative dives_
I'm interesting in this, because I use apnoe after full expiring as a warm-up for my static apnoe records.
My pulse drops to some 35 Bpm (compared with 70 Bpm during inpiring static). It spares the time and I feel much comfortable.

One thing I don't understand. What is reverse packing?
Never heard of an Invard Dive

Although I do not use reverse packing my understanding of it is when you exhale fully and then using your diaphragm to push air up while your mouth is closed...with the mouth close you are trying to pull every drop of air from your lungs with a sucking motion of your cheeks...it's a bit hard to explain...

Wouldn't recommend doing a negative pressure dive after reverse packing...other divers have experience coughing of blood after doing this...

reverse packing (with apnea) and negative pressure dives can be dangerous and should be approached with caution and never without a spotter.
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