frequent divers need less weight?

[BrentAF]

Hello,
Im looking for an article, I think it was by SSI,SDI, or NAUI. It pertained to a frequent diver requiring less weight as you rack up your dive numbers (while using the same gear) because your natural respiration is smaller since you regularly dive and your body has become used to relaxing under water, not to mention mammalian reflex, ect.

If anyone could help me find it, I've tried scouring the net but everything i find it "how to weight yourself tutorials" It may not be by one of those teaching agencies, or if you know where the actual research is located that would help to.

Thank you in advance

 

[jadairiii]

Some of that is the reality that most basic scuba classes overweight the new diver to keep them on the bottom for their "skill" work. As you dive more you begin to take some of that extra weight off, by doing that the new diver has less gas in their BC, it is easier to balance that "bubble", more streamlined and therefore, less work to move thru the water. At that point you, the new diver, will use less gas, and lower breathing rate....respiration becomes more relaxed. Sort of a Chicken/egg discussion.

 

[Doc]

+1 to jadairiii

Searching to find this “in print” somehow lends validation? I really don’t think it will, as in- you cannot know what you do not know. This all becomes clear in time, not because of some esoteric writing.

but...If you must, feel free to quote jadairiii.

 

[BlueTrin]

My personal experience is that my OW and AOW instructors had overweighted me.

Also, I had a tendency to breathe in and keep more air when task loaded.

(Only my personally experience though)


From SDI/TDI website
“Achieving proper weighting is an evolving process, and one that you will probably adapt and change many times over your dive life. More diving experience and becoming more relaxed as a diver may even result in a change of weight, as your SAC rate goes down over time. ”

The Importance of Proper Weighting - SDI | TDI | ERDI | PFI

“The last factor that can affect your buoyancy is experience. As you begin to dive more, you will notice that you start to need less weight. Often times, inexperienced divers have trouble getting all of the air out of their BC as they start their descent. Becoming more familiar with your gear and more comfortable underwater produces a more relaxed breathing cycle. Just by going out and diving, you will soon notice that you need less weight than you thought.”
How Much Weight Do I Need to be Neutrally Buoyant? - SDI | TDI | ERDI | PFI

 

[BrentAF]

The article was mostly focused on respiration and physiology, not trim and removing air from BC.

If I wasn't clear enough, the article was about the physiology mostly of instructors and DMs, or anyone that is diving 10+ a month, someone that is always in the water. Not someone trying to figure out how to weight themselves when they start diving or come back to diving. It was an article about how over time a diver that FREQUENTLY is underwater will eventually require less and less weight because their natural point between inhale and exhale becomes smaller, (since their body and mind go into "dive mode") making them less buoyant requiring less weight.

Its closer to what BlueTrin found, but more in depth.

Thank you for posting so quickly. (Sorry if this comes off in harsh tone, not trying to do that, just looking for this specific study or reference )

 

[boulderjohn]

I agree with those who say that students are usually overweighted, frequently grossly so, and it takes time to overcome that. I also agree, though, that relaxed breathing has a lot to do with it.

Like many people, I noticed the change in my first years of diving, but I had a much later revelation as well. I was a very experienced diver in general, but a relatively new technical diver, when I noticed something. On a technical dive, it would take a while to reach depth, switch gases, etc. before getting into the cruising portion of the dive. In comparison to NDL divers, technical divers must carry extra weight because of the extra gas, so there is a fair amount of air in the wing and the drysuit that needs to be balanced as you seek neutral buoyancy. As I went along at depth, I would get myself neutral. When I was satisfied with that, I would try to enter a zen state of relaxation as I swam along. As soon as I did that, I would sink and have to re-establish the buoyancy.

 

[Diving Dubai]

The primary reason is relaxation. The fight or flight reflex triggers when you’re stressed or anxious. Your diaphragm drops increasing lung volume. The second part is the adrenaline kick


Hence why on a weight check a new diver slightly stressed or anxious will need more weight Than they will when they’re more experienced

Combine this with new divers breathing in the top half or bottom half of their lungs which causes large buoyancy swings especially when coupled with large adjustments in BCD gas volume...

 

[davehicks]

The article was mostly focused on respiration and physiology, not trim and removing air from BC.

If I wasn't clear enough, the article was about the physiology mostly of instructors and DMs, or anyone that is diving 10+ a month, someone that is always in the water. Not someone trying to figure out how to weight themselves when they start diving or come back to diving. It was an article about how over time a diver that FREQUENTLY is underwater will eventually require less and less weight because their natural point between inhale and exhale becomes smaller, (since their body and mind go into "dive mode") making them less buoyant requiring less weight.

Its closer to what BlueTrin found, but more in depth.

Thank you for posting so quickly. (Sorry if this comes off in harsh tone, not trying to do that, just looking for this specific study or reference )

I'm not sold on this hypothesis about inhale/exhale. Deep breathing and breath control is what you start to do more naturally as you gain experience. You don't breath less deeply in a way that make your less buoyant. If anything you get more buoyant as you take long deep slow breaths.

You also get very accustomed to your dive gear and can adjust to minimal weighting for your dive plan. Newer divers frequently get stressed trying to descend, retain air in their lungs and BC, and over weigh themselves as a result. Instructors just bypass the stress by over weighting at the start.

 

[boulderjohn]

Here is a story that indicates the issue.

It was my very first time doing OW checkout dives as an instructor, and I had not had the students for the pool sessions. As required, the dives were shallow. This was before I knew what I learned about teaching trim, so the students had all their weight on weight belts and were not in trim. Also back then, I was still doing the skill work as I had been trained to do it, on the knees. I had the students settle to the sand for a skill session. One of them had trouble and was floating about 15 feet above us, fumbling around to find the inflator hose so he could dump air and descend. We watched intently as he finally found--not the inflator hose, but his snorkel. He held the snorkel high and pressed the bottom of it to release air from what he thought was the inflator hose. He immediately sank back down to us. The rest of the students looked at each other in wide-eyed amazement.

It made for an interesting discussion after the class, as I explained that he had let loose a sigh of relief when he found what he thought was the inflator hose, and that was all it took for him to sink to the bottom.

 

[BlueTrin]

...

Thank you for posting so quickly. (Sorry if this comes off in harsh tone, not trying to do that, just looking for this specific study or reference )

Don’t worry, this didn’t come as harsh to me.