Undercurrent--"Why Divers Die"

[MikeFerrara]

I would say that you are wrong Mike. In Australia they limit divers with a need to be certified medically. Some sort of certification to indicate you are fit to dive would not be a bad idea in this country, certainly pilots have to submit to this.

If we can demonstrate that even the fit divers can't dive well, why would be need to certify that they are fit?

Now you're advocating government regulation. ok, lets give everybody a GOOD test. Health, fitness and dive skills and the government can decide who dives and who doesn't. That'll fix it.

Pilots are required to have a license. There are no diving licenses in recreational diving in the US. Pilots carry passengers and can fly through someones house. I don't carry any passengers when I dive. I did try to dive through a house once but I got hung up on the carpet.

 

[cfelliot]

An earlier section of this article is available in part for free:
http://www.undercurrent.org/UCnow/articles/die200509.shtml

 

[DivePartner1]

Most of the articles from Undercurrent can be seen at undercurrent.org but may require subscription to the online journal. Let me quote the first line here though, "Obesity has long been considered a risk factor for decompression sickness, but Divers Alert Network (DAN) also considers it a top reason for dive fatalities."

Going on to say that "45% of dead divers had a body mass index of 30 or above".

And , "Therefore, physically unfit buddies can't always be relied upon to come to the rescue in times of need."

This from Undercurrent January 2007.

If this is so, DAN seems to be falling into the error of mistaking correlation for causation. This is bad science. One could just as accurately say "scuba diving is the leading cause of all diving deaths."

Something beyond obesity is at play, whether it is poor training, bad habits or reletive risk of heart disease that varies among all divers -- even the 'obese.'

What is going on at Duke? And what does "obesity" mean anyway?

Targeting obesity is stylishly used by everyone from health insurers -- to pass the buck on medical inflation while down- playing other causes -- to universities -- particularly if the results match the funder's expectations -- to interest groups such as the so-called the Center for Science in the Public Interest, which has said it “is proud about finding something wrong with practically everything.”

And, of course, there is an opposing point of view:

http://www.obesitymyths.com/

The truth likely lies between the extremes.

I agree with Mike that diver deaths are more likely attributable to training but depend on the unique circumstances individual to each case. Deaths are likely more preventable by training and exercise than by embarcing less meaningful health cliches or the latest political fashion de jure.

Remember how we all once worried more about starvation and the crisis of national undernourishment? What will it be next year?

 

[MikeFerrara]

Let's just throw a wrench in this one, shall we?

I'm going to speak in generalities, I'll stipulate that there are exceptions.

We can all agree that poor buoyancy control can create diving situations that are less safe, but not often fatal.

Weighting issues often lead to problems with buoyancy control, especially in newer divers.

A diver that has more body fat needs more lead to compensate for the relative 'lightness' of fat tissue over muscle.

If you add neoprene to the equation there needs to be more neoprene to cover a larger person.

Neoprene itself needs lead to offset it's inherent buoyancy.

Therefore, the more neoprene needed to cover a diver, the more lead needed for the offset.

Neoprene also compresses at depth to become less buoyant and needs more air in the BC to compensate.

The swing between the inherent buoyancy of neoprene at the surface vs. at depth becomes a greater factor the more neoprene is involved.

I don't think there is no relationship between getting a larger diver weighted properly given the relationship between the inherent buoyancy of a fully kitted diver and the neoprene compression at depth PLUS the difficulty in weighting divers with a higher percentage of body fat.

Anyone who has worked with significant numbers of divers will tell you that leaner individuals seem to have an easier time achieving proper weighting and good buoyancy control seems to come faster than dealing with bigger divers.

All speculation, of course.

Rachel

Interesting idea.

I think I've worked with a significant number of divers but I haven't noticed larger divers having more trouble with weighting. The only problem that I have noticed is that divers with no hips have trouble keeping a weight belt from sliding down around their ankles and they need more total weight.

I'll tell you what I'll do when the weather warms. I have wet suits in the garage of all sizes....I have some 3x and maybe bigger. And no, I don't wear a suit that big. They're left over from when I had a dive shop. The question is, what percentage of total balast needed is due to the suit? I'll try to get numbers but I sustpect that a very large diver may have a lower percentage of buoyancy in their suit than a skinny diver and therefor a smaller shift with depth (as a percentage) and possibly an easier (or no harder) time...when heavy suits are needed. Yes there is more neoprene but there is a lot more diver. I suspect that the net effect either way isn't much...certainly not as much as we get by just using larger tanks.

Another problem that I've noticed large people having is that they have trouble kneeling on the bottom. My answer was to stop asking them to do that.

 

[TxHockeyGuy]

I would say that you are wrong Mike. In Australia they limit divers with a need to be certified medically. Some sort of certification to indicate you are fit to dive would not be a bad idea in this country, certainly pilots have to submit to this.

And no, the article says obesity is the chief cause of death.

Why is it that so many people today think the government is responsible for their personal safety? What happened to personal responsibility?

I also think your comparison of a diver to an airline pilots is like comparing apples and oranges. Assuming you are talking about a commercial airline pilot, which I believe are the only ones who need to submit to such tests, you are talking about someone who is responsible for many more lives than a diving partner. I also have the ability to choose my dive buddy, I do not have the ability to choose my pilot. Ignoring all of that I also think that a pilot dieing during a flight greatly increases my risk level vs my buddy dieing during a dive. If my pilot dies on final approach or take off he may put the plane into an uncorrectable condition before the co-pilot can take over. If my dive buddy dies I am still 100% in control of my dive. I will do whatever I can safely do to help my buddy but I still control what happens. Granted I am probably going to be stressed and have just lost resources that could potentially help me out of a situation but I still control my own fate.

I personally do not want to see any government or agency start to require physical examinations for recreational sports. If it starts with diving how long until we need to start carrying medical examination cards before we are allowed to use public swim parks, tennis parks, jogging trails, or whatever else people start to worry about.

 

[Fish_Whisperer]

Yea, that's what I got out of the article.

I don't think you need to legislate or govern people out of diving though. As it's been stated here, people know they're overweight, know what might happen, and dive anyway. It's their choice and they should continue to be able to make it.

If you start excluding divers who display some risk factor in their behavior or physical makeup, the water will be pretty empty.

I agree: Everyone who flies, off-roads, dives, or skydives, has to sign a waiver. It's basically a form that says, "I am accepting personal, individual responsibility for my choice to participate in this activity that carries an element of risk." If someone is unwilling to accept that level of responsibility, then they have no business participating. Whether or not they are able to perform their skills to a proficient level, is something else all together.

 

[Rick Murchison]

Hmmm.... I love all this intuitively obvious stuff.
Like the inherent "badness" of body fat and being a successful aquatic mammal. How's that again?
Or like those with inherent buoyancy are more likely to drown than those who sink easier... play that by me, one more time?
Gotta love it.
Rick

 

[DivePartner1]

Hmmm.... I love all this intuitively obvious stuff.
Like the inherent "badness" of body fat and being a successful aquatic mammal. How's that again?
Or like those with inherent buoyancy are more likely to drown than those who sink easier... play that by me, one more time?
Gotta love it.
Rick

The time honoured and proven tradition of trial by ordeal established that if they sink, they're innocent; if they float, they're witches.

 

[Charlie59]

Where is the personal responsibility that will help me if I am on a dive trip with someone who is has a medical problem that they don't report and who is my buddy who needs saving at 100 ft? Again, if you risk diving with poor health and fitness and do it solo, fire away. The problem might be that unfit divers could hurt innocent divers.

What is wrong with the thought that if you love diving so much that you could use some personal responsibility to exercise, diet, and take care of your health? I would think diving could motivate some people to improve their health to extend their diving career.

Instead, we just damn the messenger and the message that we all know at some level is correct.

 

[TxHockeyGuy]

Interesting idea.

I think I've worked with a significant number of divers but I haven't noticed larger divers having more trouble with weighting. The only problem that I have noticed is that divers with no hips have trouble keeping a weight belt from sliding down around their ankles and they need more total weight.

I'll tell you what I'll do when the weather warms. I have wet suits in the garage of all sizes....I have some 3x and maybe bigger. And no, I don't wear a suit that big. They're left over from when I had a dive shop. The question is, what percentage of total balast needed is due to the suit? I'll try to get numbers but I sustpect that a very large diver may have a lower percentage of buoyancy in their suit than a skinny diver and therefor a smaller shift with depth (as a percentage) and possibly an easier (or no harder) time...when heavy suits are needed. Yes there is more neoprene but there is a lot more diver. I suspect that the net effect either way isn't much...certainly not as much as we get by just using larger tanks.

Another problem that I've noticed large people having is that they have trouble kneeling on the bottom. My answer was to stop asking them to do that.

This is speculation on my part but I don't think percentages are going to play as big a role in this experiment as you might think. If you are 2 lbs heavy you won't sink as fast being a bigger person because of the drag of the water but it still means you go down. Because the neoprene will compress more with depth I expect the bigger suit to have a much bigger buoyancy swing and cause more problems for the larger diver.

As for the inherent buoyancy of a suit I can tell you I have a 3x 7mm farmers john (and yes, I do wear a suit that big) that has 29 lbs of inherent buoyancy. I hate this suit as buoyancy is a real pain. And for those oh so worried about my health and the health of my buddy, I can probably out swim most on this board. I fully admit, I'm big, I'm fat, but I am in better shape than most.