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Kjay
06-13-2010, 10:24
Okay, I thought I'd ask a question of the experts.

I have been around some divers that have a very high BMI, somewhere in the neighborhood of 40-60 or higher perhaps. Seriously, probably more than 100 + pounds past the obese mark.

1. What does all the extra weight (fat) do to a diver?
2. weight requirements? (is more or less weight required, fat floats?
3. Health concerns at depth? (well yeah I know at the surface too).

Has there been any studies of obese people and issues with diving.

I thought staying physically fit was one of the primary tenants of dive safety, then why do I see so many overweight divers? Is it just one more product of our American Health Association Diet that has all of America fatter than ever before.


What are you: Calculate your BMI - Standard BMI Calculator (http://www.nhlbisupport.com/bmi/)
And just so you know, I'm 5'9" 210. BMI 31, 20% Body Fat, And i don't consider myself obese (but the standards folks do), and I can still beat most of those kids in the PT Test, lol.

K

FoxHound
06-13-2010, 10:58
Personally, BMI is a horrible way to judge whether someone is fit or not. In the army we have many people who go to the gym, workout constantly, lift lots of weights and run for great distances. However since they have more muscle mass, their BMI usually puts them in the overweight to obese range when they are the most fit people around. BMI does not take into conseration muscle mass compared to just straight body fat. Worse way to judge physical fitness.

However yes there are some overweight and out of shape divers out there. They only need to be cleared by their doc and pass a swim test, if they can do this, apparently they are ok to dive.

nitrogen disolves into all body tissues. It is extremely soluble in fat. If a person has a high body fat percentage, their nitrogen loading is going to be higher then that of someone without as high body fat content. This means that in reality obese divers should possibly consider shortening their NDL.

intersting read here:
Obesity and DCS (http://scuba-doc.com/obesity.html)

Lulubelle
06-13-2010, 11:13
You know, there is a very long chicken and egg conversation which could be had here.

The jury is still out a bit on whether or not it is the fat itself, or the comorbid health issues associated with obesity that lead to higher risks of DCS. Check out the DAN guidance.

Agreed that BMI is a horrible way to measure fitness.

I got some extra bioprene last fall due to some meds I had to take. I still have the bioprene. I went to see a dive doc at Duke to ask about how I should adjust my diving and to look at my CV fitness. He wasn't concerned about my CV fitness (all measures look great) or my weight gain. He said that most of the bent divers they see at Duke are thin. So who knows.

From what I have read though, there is the possibility of impaired gas exchange if you have extra bioprene. That would explain why women get bent more than men. So I have adjusted my diving on deep dives to include a safety stop at 40 feet or so, and a longer one at 15 feet.

Don't assume that someone's body habitus has anything to do with their fitness level. It may, it may not.

LeeParrish
06-13-2010, 12:34
Last time I scanned over the DAN stats on diver injuries it seemed that a lot of the accidents that were listed had "high BMI" as one of the characteristics. Now these aren't only fatalities due to DCS, but any reported fatality that was in-water during scuba or free diving, so it may be just that people with extremely high BMI (due to being overweight, not due to being extremely fit) also have higher cardiac disease occurence and those accidents (heart attack while in water) end up listed in their stats.

I'll also agree that BMI isn't a perfect way to measure physical health, let's face it, here in the US at least, there are probably 99 people with a high BMI due to being overweight for every 1 that is there because they are extremely fit and carrying around more than normal muscle mass. And I'm probably being generous on those numbers.

PTAaron
06-13-2010, 14:17
I don't have answers as to relationship to DCS, but I need to comment on BMI.

BMI is a horrible way to measure bodyfat/fitness level. As an example my BMI is 35 (6'1" 265lbs) - which puts me well beyond the "obese" category. I'm not all that concerned though because even if I were at 5-10% bodyfat I would still be almost in the "obese" range! Most of my friends have the same issue since we are all bodybuilders or people that work out heavily with weights.

I would be less concerned about BMI and more concerned about bodyfat levels and cardiovascular fitness level.

Lulubelle
06-13-2010, 14:21
Last time I scanned over the DAN stats on diver injuries it seemed that a lot of the accidents that were listed had "high BMI" as one of the characteristics. Now these aren't only fatalities due to DCS, but any reported fatality that was in-water during scuba or free diving, so it may be just that people with extremely high BMI (due to being overweight, not due to being extremely fit) also have higher cardiac disease occurence and those accidents (heart attack while in water) end up listed in their stats.

I'll also agree that BMI isn't a perfect way to measure physical health, let's face it, here in the US at least, there are probably 99 people with a high BMI due to being overweight for every 1 that is there because they are extremely fit and carrying around more than normal muscle mass. And I'm probably being generous on those numbers.

You are probably right Lee, the doctor's comment about most of the divers who were bent being thin was in no way related to diver deaths.

BRsnow
06-13-2010, 18:54
According to charts my BMI is at the high part of normal, but I have about 12% percent body fat, so the weight/age/height thing does not really work for me. I realize there are many over weight people out there, but heck diving is a bit of a workout I suppose...so more the better. The more activity the better a person is off in the long run...BR

bigman241
06-13-2010, 21:44
I was going to a gym as a kid. They did all kinds of test to find a persons bmi. I think the norm is a tub of water. You mark the water level empty insert the "fat" person and mark the water. Then with some long math that would make a person's head spin. They come up with your bmi. I am a 6'4 488 pound diver. Yes I said 488, with that my bmi shows up as 59.3 with the site you gave. I have bad knees a bad back, I messed up my shoulder slipping on ice and landing on my shoulder. My doctor who did a few dives, instructor and shop owner all said I was clear for diving. I checked and found out about the risk of dcs. Am I at higher risk for a heart attack, stroke, and dcs when diving sure. I would rather die under 60 feet of water. Then die in a chair. Since Getting my cert I am started down the healthy road. Lost 20 pounds in 10 days and still going down. Seems I have been told over and over alot fo overweight people dive because it has reduce affects on joints and such. IE no knee or back pain. It does with me I can swim a mile with my fins on with no trouble. Walk 1/4 mile down the sidewalk of around the park and my knees and back kill me.

tfd86
06-14-2010, 05:42
I'd seriously think that diver mortality rate from high BMI come from undue stresses on the cardiovascular system then from DCS from Nitrogen Load. Take any out of shape person add 75 lbs of weight to them put them in a atmosphere where they can't use the bodies natural cooling and make them do more work. All this equals heat stress with major increased cardiac workload, all where in the dangerous confines of underwater environment equals catastrophy.

DMWiz
06-14-2010, 08:59
Okay, I thought I'd ask a question of the experts.

I have been around some divers that have a very high BMI, somewhere in the neighborhood of 40-60 or higher perhaps. Seriously, probably more than 100 + pounds past the obese mark.

I thought staying physically fit was one of the primary tenants of dive safety, then why do I see so many overweight divers? Is it just one more product of our American Health Association Diet that has all of America fatter than ever before.


I think what you observed is not limited to diving. It's just magnified <no pun intended> by the fact that you see divers usually wearing less clothing than normal.

BTW, do you really mean American Hearth Association diet (http://www.americanheart.org/presenter.jhtml?identifier=3071616) or American Health Association (http://www.ahahealth.com/index.cfm) diet? Cause neither one of those entities promotes bad eating habits. Most americas consume well over 2000 calories a day.


I'd seriously think that diver mortality rate from high BMI come from undue stresses on the cardiovascular system then from DCS from Nitrogen Load.

I agree with you... although I don't have any hard evidence to back it up!
Scuba diving is hardly a strenuous activity. Heck I get more of a workout playing softball than diving. However, when something goes wrong a diver can easily get exhausted and panic. That IMO is when being overweight or not physically fit as a diver can be dangerous.

cyclone3565
06-14-2010, 09:11
I would certainly agree about BMI being a horrible way to judge fitness, however, I believe noone that weighs 400 pounds or even 300 can be in good shape. We just got back from Cozumel last night, and some of the divers I saw on boats had to clock in at that range. I can't imagine anyone in that range being fit or even thinking they are fit.

dburg30
06-14-2010, 10:41
No doubt that is one thing that I have to do as I go thru my certification. I am overweight, probably borderline obese. I know I need to loose weight and get in better shape to be a safer more efficient diver. I'm hoping that since i want to do this so badly, it'll give me the kick in the butt to get that done!

tfd86
06-14-2010, 12:18
Okay, I thought I'd ask a question of the experts.

I have been around some divers that have a very high BMI, somewhere in the neighborhood of 40-60 or higher perhaps. Seriously, probably more than 100 + pounds past the obese mark.

I thought staying physically fit was one of the primary tenants of dive safety, then why do I see so many overweight divers? Is it just one more product of our American Health Association Diet that has all of America fatter than ever before.


I think what you observed is not limited to diving. It's just magnified <no pun intended> by the fact that you see divers usually wearing less clothing than normal.

BTW, do you really mean American Hearth Association diet (http://www.americanheart.org/presenter.jhtml?identifier=3071616) or American Health Association (http://www.ahahealth.com/index.cfm) diet? Cause neither one of those entities promotes bad eating habits. Most americas consume well over 2000 calories a day.


I'd seriously think that diver mortality rate from high BMI come from undue stresses on the cardiovascular system then from DCS from Nitrogen Load.

I agree with you... although I don't have any hard evidence to back it up!
Scuba diving is hardly a strenuous activity. Heck I get more of a workout playing softball than diving. However, when something goes wrong a diver can easily get exhausted and panic. That IMO is when being overweight or not physically fit as a diver can be dangerous.


Fine if someone carries your gear to the dive site and drops you in the water right over the wreck then drives the boat over to you and usues a lift system to extract you from the water. Just think about the last time you visualized a out of shape person trying to climb a boat ladder with all their gear on:smiley5:

DMWiz
06-14-2010, 12:49
Just because someone may have difficulty getting in and out of the water does not make the activity difficult. Sure if I have to climb a steep cliff in California to shore dive or hike a mile fully geared to get into a cave in Mexico that would require a great deal of effort, but the diving itself would not.

Kjay
06-15-2010, 01:13
@DMWiz, yes American Heart Association - et al, no I donít' agree that BMI is the only standard, but, but, but, it is a good place to start and I realize that Iím not an Olympic athlete, I do my part and itís not enough, but I try to make sure Iím not the guy who couldnít perform at depth when my dive buddy needed me.

Gang, my issue is what the experts have been telling American's for 40 years is not necessarily in their best interests. We as a society have become to accustom to 'fast food' which is killing us one pound at a time. I'm no expert, as stated in my original post.

First I would like to offer up this chart comparison http://www.disabled-world.com/artman/publish/food_pyramid.shtml (http://www.disabled-world.com/artman/publish/food_pyramid.shtml) of the old diet that most of us over the age of say 25 learned vs the new one they teach today.

There has been some very good discussion here on BMI vs Fat Percentages; I would like to offer up http://www.nwhealth.edu/healthyU/keepLean/bmi.html (http://www.nwhealth.edu/healthyU/keepLean/bmi.html) as a good comparison, which I agree with. BMI is not a good indicator, but its a good place to start, and if you have a BMI of 40 and have yourself checked and have a BFP of 12%, then BMI isn't for you. But awareness is the key.

Statistics are hard to ignore, please take a look at what we are doing to ourselves http://www.cdc.gov/obesity/data/trends.html (http://www.cdc.gov/obesity/data/trends.html).

If I've offended you, I'm sorry, if you feel insulted, I'm Sorry. If you should do something to get off the bad boy list, thank me later.

K

DivingCRNA
06-15-2010, 07:10
Everyone thinks the are "in good shape". It is part of the immortality we all have. No one admits they are getting slower or that they have a paunch. But we are a country that sits on out butts and thinks a nice after dinner walk is exercise.

While BMI may not be a great way to judge fitness if people of close to normal weight, a 40+ BMI cannot possibly be good. Really, lets be honest, if the weight is muscle or fat, it is going to wear joints out faster at the very least.

I really would say body fat percentage, adjusted slightly for gender, is a good measure of fitness.

Here is the real dive issue with lots of body fat: Fat is not very vascular (it does not have a lot of blood flow). In anesthesia, fat people will wake up slower. Why?

It takes longer for that fat to load up with anesthesia gas because of the reduced blood flow, but once it is saturated with anesthesia gas it also off gasses slowly. The very same thing happens with nitrogen and other inert gasses when we SCUBA dive. So, logically, fat people should be at a much higher risk of DCS than thin people. The fat stores nitrogen for a longer time.

To explain the Duke dive doc's observation: I would guess that the bent folks he sees are the young, full of piss and vinegar, guys that are pushing the limits of the tables and computers that have not realized they can get hurt.

TwistedSister209
06-15-2010, 19:26
I have lots of bioprene, and I don't claim to 'be fit,' yet I'm out exercising-walking, ranch work, DM interning OW classes, and dirt track racing.

IF I ask a younger guy to carry my tanks from the car to the shore, or am assisted with my gear in and out of the water, that doesn't make me weak. Makes me smart as I can realize some of my limitations--being fat isn't one of them--a torn ACL, bruised hip and moderate arthritis.
I think I proved that my bulk didn't get in the way with the DM skills as I swam with a triathlete who had a hard time treadding water, and only finished 45 seconds before I did in the 800 m swim.
If I have to rescue someone whose a bit bigger than normal, I won't be alone...or worry about his/her weight.

scubaman450
06-15-2010, 22:42
I know how people on the "big side" feel, for years I was always on the big side myself....5'9" 215 and never needed anyone to help me with my work in anyway shape or from I have been a biulder from the time I got out of the Navy and that IS work.
Now at 52 I felt myself start to huff and puff up the hills and no longer would be able to work those long hard days without hurting and I also no longer was turning the heads of the girls.....
6 months ago I turned all that around I started a wieghtlifting workout routin and sick with it, at first I lost almost 40bls then it started to go up to end up at 188lbs But now I'm buffed out and run up those hills my arms are 18inch and I can pack all my diving gear in one trip over rocks and sand.
I have never felt this good.....I use to say I'm not fat I'm just big. Well NOW I'm big and before I was FAT.
It's a hard pill to take but do yourself a big Hess....Take that pill now before you die of something you where able to do somthing about and didn't.
If your 5'9" and come in at 210 ask yourself this Can you do 10 chin-up 20 push-up run for 2 miles and swim for 2 hours? I'm 52 I can, However be that as it may, before I got down to takeing care of myself I was unable to do these things.
We live in the Strongest nations in the world yet we are the most flaby by far.
Like I said it's a bitter pill to take, and yea It's just my way at seeing it and my way will not be the same as many, But I was there in your fins and I didn't like it.

DivingCRNA
06-16-2010, 07:54
I have lots of bioprene, and I don't claim to 'be fit,' yet I'm out exercising-walking, ranch work, DM interning OW classes, and dirt track racing.

IF I ask a younger guy to carry my tanks from the car to the shore, or am assisted with my gear in and out of the water, that doesn't make me weak. Makes me smart as I can realize some of my limitations--being fat isn't one of them--a torn ACL, bruised hip and moderate arthritis.
I think I proved that my bulk didn't get in the way with the DM skills as I swam with a triathlete who had a hard time treadding water, and only finished 45 seconds before I did in the 800 m swim.
If I have to rescue someone whose a bit bigger than normal, I won't be alone...or worry about his/her weight.

I was talking with a DMC with a lot of bioprene about the swims and she did the "tread" without a problem because she floats. I struggled a lot. I can tread water and swim, but my body fat was around 13-14% when I did it. I do NOT float.

Another thing to consider-if a diver is not obese, then you do not have to wear all that much lead just to sink. I do not wear any lead in my recreational set-up when I am in a 3 ml shorty. I put 16 pounds on a fat kid during discover scuba last weekend, and he did not have on a wetsuit!

People complain about lead weights when diving all the time. One way to rid yourself of some of that is to actually lose weight.

scubaman450
06-16-2010, 09:43
I have lots of bioprene, and I don't claim to 'be fit,' yet I'm out exercising-walking, ranch work, DM interning OW classes, and dirt track racing.

IF I ask a younger guy to carry my tanks from the car to the shore, or am assisted with my gear in and out of the water, that doesn't make me weak. Makes me smart as I can realize some of my limitations--being fat isn't one of them--a torn ACL, bruised hip and moderate arthritis.
I think I proved that my bulk didn't get in the way with the DM skills as I swam with a triathlete who had a hard time treadding water, and only finished 45 seconds before I did in the 800 m swim.
If I have to rescue someone whose a bit bigger than normal, I won't be alone...or worry about his/her weight.

I was talking with a DMC with a lot of bioprene about the swims and she did the "tread" without a problem because she floats. I struggled a lot. I can tread water and swim, but my body fat was around 13-14% when I did it. I do NOT float.

Another thing to consider-if a diver is not obese, then you do not have to wear all that much lead just to sink. I do not wear any lead in my recreational set-up when I am in a 3 ml shorty. I put 16 pounds on a fat kid during discover scuba last weekend, and he did not have on a wetsuit!

People complain about lead weights when diving all the time. One way to rid yourself of some of that is to actually lose weight.


Good point...after loseing wieght and toning up I put on my 7mm and was amazed at how much better it fit and I dropped 6bls of lead.....at one time I was useing 28bls of lead to cold water dive.
Floating is nice and then so is not huffing and puffing on the beach. Believe me get in shape and you will feel better, look better and your loved one's will not have that "look" when you come in the room. You know what I'm talking about,,,,I seen it for years. You don't have to give up on your life,just change some of it. It's not even that hard, hey it's not as hard as it is to make a bow out of your shoelaseis standing up. Poeple that have seen me go from Fat to fit all and I mean all of them ask ME how they can do it. I tell them all the same thing.....eat 5 or 6 fist size meals a day,one every 2 or 3 hours No bad fats,no suger,nothing out of a fast food joint (Mc upchucks) and just start to get your heart rate up By funning or joging or what ever. As you feel better you will start to look for the work out that really works for you! Believe me Good food only seems to have no flavor, thats just for a little bit of time......You will see just how good things that grow out of the earth REALLY are once you stop putting MAN-MADE junk into mouth. If the food you eat has more then 4 things in it don't eat it.
There is ton's of FREE work outs on Youtube and "used"fittness gear is down right cheep, heck half of what I have was given to me by folk's that told me for one reson on the other that they CAN'T work out==BS== anyone that wishess to be fit can be.

bigman241
06-16-2010, 14:13
I am right here no need to visualize. 6'4 478 pounds 495 when I did my cert. I went in with a steel 120 about the heaviest tank out there, 50 pounds of lead, ranger ltd, huge wetsuit and i was fine. I carried all my gear on the boat, loaded all my weights in the bc, put my bc on the tanks and off, put my bc on stood up by myself and got in the water with no help but to make sure I did not fall over from the boat rolling. Everyone had the same help more of I am here in case you start to fall. Though not sure how a 5'6 blond would stop me from falling :smiley36:. I had no trouble getting up and in the water. I found diving to be rather easy and not near has much work as my common mile plus hikes in the woods carrying any where from 40 to 75 pounds of hunting gear. When we were done diving I had no trouble getting up the ladder and in the water. In fact I had less trouble then most veteran divers. One guy and his wife had to remove their weights and bc before getting up and they where both skinny.

Here is why I see I had no trouble. I hike hunt fish work everyday with 475 pounds on my legs back and feet. Though I have a bad knee bad back and have trouble with my feet. My leg muscles are rock hard. In middle school I could leg press 800 pounds. About double the highschool kids. In fact I am 90% my name is still on the record board at the highschool for leg press. The record before we started going down their one day a week for gym was 500 pounds.
My body and legs deal with the weight every day. SO adding the 100 pounds or so had little effect if any on my legs. I think I could have went down with doubles or twice the lead and had no issue. The other day I walked up a gravel boat ramp with my gear, an al80, and 40 pounds of lead on. walked12 or so feet to the truck and sat down on the tailgate to take it off.
Though I differ from most fat people. I hike miles into the woods to hunt. I have swam 1.5 miles twice in the last two weeks snorkeling, I tend to got hike and swim alot of skinny people. SO I am alittle in shape better then most people who weigh 100 or even 200 pounds less then I do.

Sure I would like to be 250 pounds and I am working on it. Though i have seen no issue that would keep me from diving safe. Though I tend to question how even 3 or 4 people could lift me out of the water into a boat or on shore. :smiley9:


Okay, I thought I'd ask a question of the experts.

I have been around some divers that have a very high BMI, somewhere in the neighborhood of 40-60 or higher perhaps. Seriously, probably more than 100 + pounds past the obese mark.

I thought staying physically fit was one of the primary tenants of dive safety, then why do I see so many overweight divers? Is it just one more product of our American Health Association Diet that has all of America fatter than ever before.


I think what you observed is not limited to diving. It's just magnified <no pun intended> by the fact that you see divers usually wearing less clothing than normal.

BTW, do you really mean American Hearth Association diet (http://www.americanheart.org/presenter.jhtml?identifier=3071616) or American Health Association (http://www.ahahealth.com/index.cfm) diet? Cause neither one of those entities promotes bad eating habits. Most americas consume well over 2000 calories a day.


I'd seriously think that diver mortality rate from high BMI come from undue stresses on the cardiovascular system then from DCS from Nitrogen Load.

I agree with you... although I don't have any hard evidence to back it up!
Scuba diving is hardly a strenuous activity. Heck I get more of a workout playing softball than diving. However, when something goes wrong a diver can easily get exhausted and panic. That IMO is when being overweight or not physically fit as a diver can be dangerous.


Fine if someone carries your gear to the dive site and drops you in the water right over the wreck then drives the boat over to you and usues a lift system to extract you from the water. Just think about the last time you visualized a out of shape person trying to climb a boat ladder with all their gear on:smiley5:

scubaman450
06-16-2010, 15:00
Big,
Right now your young, that will not last and as you get older you will suffer far and away wose then a "skiny" person if you don't trim it off.

Kjay
06-17-2010, 01:06
Gang, I really appreciate the discussion that is taking place here. Some very interesting comments. If nothing else this thread has forced me to research more on this subject, and look for qualitative answers to some of the 'myths' I thought were truths. So much so that I want to add a little 'surfing' that I did.

Pound for pound Fat and muscle are the same.
Muscle Weighs More Than Fat Myth (http://www.onemorebite-weightloss.com/muscle-to-fat.html)

So then, I had to do some math. Muscle density is 1.06 g/ml and fat density is (about) 0.9 g/ml. So help me out, my math sucks.

So, Muscle will be 17% smaller and weigh the same amount as fat.

Found what I believe is the answer to 'fat floats': The density of fat mass and fat-free mass are constant, and lean tissue is more dense than water and fat tissue is less dense than water, therefore a person with more body fat will weigh less underwater and be more buoyant.

Jolie Bookspan's "The 36 Most Common Diving Physiology Myths" I quote her work on DCS here: "Fat is a slow tissue due to gas solubility. Because of high gas solubility, fat holds much nitrogen and takes time to uptake and offgas it all. This is a property of fat and is true even for fatty areas with the same degree of blood supply as leaner tissue."
https://www.msu.edu/user/manns/myths.html

My Question of the day:

I have lots of bioprene Could someone help me out, I'm assuming this means fat but I can't find a definition for it.

Fat used as an adjective meaning overweight: beefy, big, blimp, bovine, brawny, broad, bulging, bulky, bull, burly, butterball, chunky, corpulent, distended, dumpy, elephantine, fleshy, gargantuan, gross, heavy, heavyset, hefty, husky, inflated, jelly-belly, lard, large, meaty, obese, oversize, paunchy, plump, plumpish, ponderous, porcine, portly, potbellied, pudgy, roly-poly, rotund, solid, stout, swollen, thickset, weighty, whalelike

Fat used as an adjective meaning containing an oily substance: adipose, fatlike, fatty, greasy, oleaginous, suety, unctuous

Fat used as an noun meaning overweight, adipose tissue: blubber, bulk, cellulite, corpulence, excess, fatness, flab, flesh, grease, lard, obesity, overabundance, overflow, paunch, plethora, suet, superfluity, surfeit, surplus, tallow

I'm thinking some would like this definition best:

Fat used as an noun meaning productive, rich: affluent, cushy, fertile, flourishing, fruitful, good, lucrative, lush, profitable, prosperous, remunerative, thriving.

Lulubelle
06-17-2010, 05:46
My Question of the day:

I have lots of bioprene Could someone help me out, I'm assuming this means fat but I can't find a definition for it.



Diver slang kjay, skinny people may have to use more neoprene for thermal protection making them more buoyant. Folks with some extra "bioprene" may not and are more naturally buoyant.

There are a lot of assumptions here about why people who are overweight are overweight and what it means to their overall fitness level and fitness to dive. The bottom line is that overweight people are not known to be at any greater risk for DCI than people at normal weight. But no doubt, they are more likely to have other comorbid issues which could lead to other problems while diving.

Here's the bottom line, from DAN:

Consider two questions:
(1) Will an overweight individual suffer any ill health effects by diving? and
(2) Will this individual be able to perform all of the necessary skills to dive successfully?



I hope people will get back to this being the essential question. Skinny is not always healthy (I am thinking of one chain smoking substance using instructor whom I knew and saw diving), fat is not always as unhealthy as you think (the overweight person who exercises regularly) within limits of course. I had a friend who would not take the steroids necessary for her condition because of the associated weight gain. So she chose skinny and sick as crap. That's certainly not healthy. Were she a diver, I would rather dive with her if she was overweight and her condition was in good control.

LeeParrish
06-17-2010, 06:08
Pound for pound Fat and muscle are the same.
Muscle Weighs More Than Fat Myth (http://www.onemorebite-weightloss.com/muscle-to-fat.html)


Though this is nothing but stating the old joke, "What weighs more, a pound of feathers or a pound of lead?". Weight isn't the issue, it's density.



So then, I had to do some math. Muscle density is 1.06 g/ml and fat density is (about) 0.9 g/ml. So help me out, my math sucks.

So, Muscle will be 17% smaller and weigh the same amount as fat.

Found what I believe is the answer to 'fat floats': The density of fat mass and fat-free mass are constant, and lean tissue is more dense than water and fat tissue is less dense than water, therefore a person with more body fat will weigh less underwater and be more buoyant.



Right, this is exactly why fat floats, and muscle sinks. Fresh water is 1.0 g/ml so if you put something that is less than 1 g/ml in water it will displace more water than it's own weight and tend to float. Now, that is fresh water, salt water actually weighs more at 1.025 (average) g/ml from the dissolved salts.

LeeParrish
06-17-2010, 06:27
I hope people will get back to this being the essential question. Skinny is not always healthy (I am thinking of one chain smoking substance using instructor whom I knew and saw diving), fat is not always as unhealthy as you think (the overweight person who exercises regularly) within limits of course. I had a friend who would not take the steroids necessary for her condition because of the associated weight gain. So she chose skinny and sick as crap. That's certainly not healthy. Were she a diver, I would rather dive with her if she was overweight and her condition was in good control.

Agreed, but in your example the "skinny" person wasn't in poor health due to their weight, but chain smoking. In general though a thin person will be healthier than a fat people of the same fitness level just from the fact that there are many health issues related to excess weight. Now we aren't talking the difference between say a man 6' tall and 170 lbs versus 180 lbs, we are talking 170 lbs versus say 220+ lbs. Many diseases are proven to be linked to being overweight; diabetes, coronary disease, increased wear on joints, etc. So yes, while carrying a few pounds extra around doesn't necessarily mean you are in poor health and that you can't be physically fit; you can't say someone is in better general health due to having extra fat.

Lulubelle
06-17-2010, 07:04
Agreed, but in your example the "skinny" person wasn't in poor health due to their weight, but chain smoking. In general though a thin person will be healthier than a fat people of the same fitness level just from the fact that there are many health issues related to excess weight. Now we aren't talking the difference between say a man 6' tall and 170 lbs versus 180 lbs, we are talking 170 lbs versus say 220+ lbs. Many diseases are proven to be linked to being overweight; diabetes, coronary disease, increased wear on joints, etc. So yes, while carrying a few pounds extra around doesn't necessarily mean you are in poor health and that you can't be physically fit; you can't say someone is in better general health due to having extra fat.

But to the casual observer, that skinny substance using instructor would have likely "appeared" to have been healthier than someone who was overweight. As would my slim sick as crap friend.

I didn't say that people in general were healthier if they had extra fat, of course they aren't. But I most certainly CAN say that there are circumstances where someone would be in better general health with extra fat if there was not a choice to be healthy without it. My friend who would not take her prescribed steroids was very debilitated from her illness. She would have been in FAR better health by taking the steroids and gaining a few pounds, rather than forgoing them, staying skinny, and being sick as crap. But such is our culture.

My point, and my last one, is that no one argues that a healthy body weight is optimal for most people. But NOT if it comes at the expense that it has come for these two people. They would be healthier if they were a bit pudgier. The smoker/substance abuser probably has the choice to be healthy AND slim. My friend, perhaps over the long haul, does too.

I measure health in dive buddies by strength, fitness, lifestyle, eating habits, etc. Body habitus is just a small piece of that assessment. And I darn well expect them to own up to any underlying issues that I cannot see.

LeeParrish
06-17-2010, 07:30
Agreed, but in your example the "skinny" person wasn't in poor health due to their weight, but chain smoking. In general though a thin person will be healthier than a fat people of the same fitness level just from the fact that there are many health issues related to excess weight. Now we aren't talking the difference between say a man 6' tall and 170 lbs versus 180 lbs, we are talking 170 lbs versus say 220+ lbs. Many diseases are proven to be linked to being overweight; diabetes, coronary disease, increased wear on joints, etc. So yes, while carrying a few pounds extra around doesn't necessarily mean you are in poor health and that you can't be physically fit; you can't say someone is in better general health due to having extra fat.

But to the casual observer, that skinny substance using instructor would have likely "appeared" to have been healthier than someone who was overweight. As would my slim sick as crap friend.

I didn't say that people in general were healthier if they had extra fat, of course they aren't. But I most certainly CAN say that there are circumstances where someone would be in better general health with extra fat if there was not a choice to be healthy without it. My friend who would not take her prescribed steroids was very debilitated from her illness. She would have been in FAR better health by taking the steroids and gaining a few pounds, rather than forgoing them, staying skinny, and being sick as crap. But such is our culture.

My point, and my last one, is that no one argues that a healthy body weight is optimal for most people. But NOT if it comes at the expense that it has come for these two people. They would be healthier if they were a bit pudgier. The smoker/substance abuser probably has the choice to be healthy AND slim. My friend, perhaps over the long haul, does too.

I measure health in dive buddies by strength, fitness, lifestyle, eating habits, etc. Body habitus is just a small piece of that assessment. And I darn well expect them to own up to any underlying issues that I cannot see.

Couldn't agree more :smiley20:. I've had good and not so good dive buddies of all shapes and sizes. And I've never observed myself there really being any correlation between size/weight and their ability to be a good diver/buddy.

Lulubelle
06-17-2010, 07:36
Really, at the end of the day, everyone should look at their lives, and the lives of others, and focus on HEALTH. The skinny chain smoker would be well advised to quit. If he gains a FEW pounds in the process, it is probably still a net positive, although ideally, he won't gain. My friend would be well advised to take the steroids, control her condition, and get strong enough to exercise and eat well (she has a gi condition which when uncontrolled, severely restricts her intake of vegetables, fruits, grains, and nuts). She may gain a few pounds in the process, but again, it will be a net positive.

As for the overweight who eat too much crap and don't exercise enough, get busy.

Bigman, you are young and strong now. Getting your weight down, if you can, will keep you that way. Trust me, over time, it will have a negative impact. And it is far easier to lose it while you are young. And you make a good point about it being possibly difficult for your buddy to tow you if you are in distress. But if they can get you to the surface and get your head above water, they should be able to help you. Probably not a good idea to dive with an 80 pound girl though.

Now who wants to go for a leisurely 16 mile walk with me this weekend? :smiley2:

LeeParrish
06-17-2010, 07:47
Best thing I ever did for my own health/fitness was my wife/daughter bought a dog 5 years ago that was pretty high energy. So to satisfy it I have had to take it on a couple mile walk every day, rain or shine, hot or cold. Which is a problem now, since the dog had ACL surgery 5 weeks ago and isn't able to go on long walks (yet). And I can't go without the dog, he just sits at the front door and looks at me sad when I come back. So I have to resort to sneaking out in the car, parking down the street, and then driving back home when I'm done. It would be easier if I didn't work out of my house and could just do it before/after work. I feel so ashamed cheating on my dog...

cyclone3565
06-17-2010, 08:36
I still contend that 6'5" and 400 some pounds cannot be healthy. The viscral (spelling?) fat that must surrond all organs, the fat in the veins, everywhere. Do instructors have an obligation to get medical releases for someone that big. What if something happens, should boats be required to keep engine hoists handy so there is not another lawsuit like there was a year or so ago, where it took (5) people to hoist someone back on the boat. I think one must stand back and say " I am not fit" "I can't be fit and in good health" at some point.

PTAaron
06-17-2010, 08:43
I just want to interject one more thing: the term "overfat" would be more appropriate to the discussion at hand, rather than "overweight". I personally have been much heavier than other people my same height, with lower bodyfat and much higher level of fitness. Based on the discussion related to fat storing nitrogen longer - it really points to the fact that bodyfat levels are much more important.

I only bring this up because of some of the comments relating to "appropriate" bodyweight. I know for me personally at 6'1" my lean body mass (using bodyfat percentage and subtracting the fat mass) is still over 200lbs - going by weight alone some of you would still believe that to be "overweight" and unhealthy - even though that is the weight with no fat at all. In bigman's case: being that he has been so heavy for so long, and that he is 6'4" I would not be surprised if he go to 10% bodyfat and was still over 250lbs. Still "overweight" but certainly not "overfat".

I know this isn't the point of the discussion really, but it is a pet peeve of mine when I see generalizations about health based on factors that may or may not be accurate. I get it a lot when patients hear how much I weigh and say (in a sympathetic tone) "oh, but you don't look that fat"! I know... I'm not fat ;)

anyway - back to the discussion :D

cyclone3565
06-17-2010, 08:49
I could not agree more, overfat is the discussion. I am 5'10 and at 170 would look like a match.

DivingCRNA
06-17-2010, 09:30
"Jolie Bookspan's "The 36 Most Common Diving Physiology Myths" I quote her work on DCS here: "Fat is a slow tissue due to gas solubility. Because of high gas solubility, fat holds much nitrogen and takes time to uptake and offgas it all. This is a property of fat and is true even for fatty areas with the same degree of blood supply as leaner tissue."
https://www.msu.edu/user/manns/myths.html"

This is the physiologic/scientific basis for my comments. I did not comment in any way on HOW a person got fat or WHY they got fat. Adipose tissue is slow at releasing dissolved gasses. Period. The end.

It is not personal. It does not label the adipose rich person. It does not say if you are a good diver or a bad diver. It does not say if skinny people look better than fat people. It does not say "curvy" is better than "stick person". It does not say if you are a dug addict or not. It describes the physiology of what can lead to DCS.

If you really want to point fingers at what can hurt a diver that they do on purpose and can absolutely prevent, look at SMOKING.

bigman241
06-17-2010, 11:51
I am alittle surpised there is so much verying opinions on the subject. I think when we remove the fat thing. Like you said not how some got fat how they look weather we want to see a fat guy putting on a tight wetsuit.
It comes down to the fact that yes the fatter you are the more risk. Everyone I have talked to about this has said the same thing. It is the main reason I want to do nitrox and dive with normal padi tables. Diving nitrox when on padi air tables I reduce that risk. I remember a discussion in high school about how pot would stay in your system longer the more fat you have. Though I never had a to worry about that.
"Jolie Bookspan's "The 36 Most Common Diving Physiology Myths" I quote her work on DCS here: "Fat is a slow tissue due to gas solubility. Because of high gas solubility, fat holds much nitrogen and takes time to uptake and offgas it all. This is a property of fat and is true even for fatty areas with the same degree of blood supply as leaner tissue."
https://www.msu.edu/user/manns/myths.html"

This is the physiologic/scientific basis for my comments. I did not comment in any way on HOW a person got fat or WHY they got fat. Adipose tissue is slow at releasing dissolved gasses. Period. The end.

It is not personal. It does not label the adipose rich person. It does not say if you are a good diver or a bad diver. It does not say if skinny people look better than fat people. It does not say "curvy" is better than "stick person". It does not say if you are a dug addict or not. It describes the physiology of what can lead to DCS.

If you really want to point fingers at what can hurt a diver that they do on purpose and can absolutely prevent, look at SMOKING.

DMWiz
06-17-2010, 19:50
I just want to interject one more thing: the term "overfat" would be more appropriate to the discussion at hand, rather than "overweight". I personally have been much heavier than other people my same height, with lower bodyfat and much higher level of fitness. Based on the discussion related to fat storing nitrogen longer - it really points to the fact that bodyfat levels are much more important.

I only bring this up because of some of the comments relating to "appropriate" bodyweight. I know for me personally at 6'1" my lean body mass (using bodyfat percentage and subtracting the fat mass) is still over 200lbs - going by weight alone some of you would still believe that to be "overweight" and unhealthy - even though that is the weight with no fat at all. In bigman's case: being that he has been so heavy for so long, and that he is 6'4" I would not be surprised if he go to 10% bodyfat and was still over 250lbs. Still "overweight" but certainly not "overfat".

I know this isn't the point of the discussion really, but it is a pet peeve of mine when I see generalizations about health based on factors that may or may not be accurate. I get it a lot when patients hear how much I weigh and say (in a sympathetic tone) "oh, but you don't loom that fat"! I know... I'm not fat ;)

anyway - back to the discussion :D

I think it's very relevant to the discussion... That's why so many people believe BMI is a very inaccurate way to measure someone's fitness level. If your body type does not fit the BMI box then your number will be high. HOWEVER, as someone pointed out, it is a great guideline for a large number of people.

BTW, at 6'5" and 10-12% body fat I'm 225-230. I'm 16 pounds away:smiley11: Which would put me in the very high range of my ideal BMI.

mitsuguy
06-18-2010, 04:40
I think it's very relevant to the discussion... That's why so many people believe BMI is a very inaccurate way to measure someone's fitness level. If your body type does not fit the BMI box then your number will be high. HOWEVER, as someone pointed out, it is a great guideline for a large number of people.

BTW, at 6'5" and 10-12% body fat I'm 225-230. I'm 16 pounds away:smiley11: Which would put me in the very high range of my ideal BMI.

BMI may work for some people, but definitely not for all of us... I recently had a physical to obtain my captains license. It comes in at 29, just one point under obese. I have a little bit of a gut, but not much at all... When the doctor did the calculation, she was even surprised...

When I first started working as a divemaster / instructor, I went down from 210 to 185, which would have put my BMI within 1 point of normal. I lost 2 inches around the waist. Now, I am still the same waist size, but back to 205ish, and hardly any fat. I gained all the weight back as muscle mass. I have extremely low air consumption underwater, and regularly move 30-40 tanks in and out of a truck, on and off a boat without getting winded or tired. When I stand next to other people my height, I am 2-4 inches wider than them at the shoulders. Also, when it comes to fitness, I kayak to and from our boat regularly, the days I don't kayak, I swim.

Although I haven't actually had it measured recently, I have less fat on my arms, legs, shoulders, and back than I did when I was measured with 12% body fat... My thighs are solid muscle and 25" around...

I feel much healthier than when I used to weigh 150 and this same height - I looked way too skinny, completely unhealthy and was weak, in comparison.

So, one last time BMI may work for some, but it is a horrible way to judge whether someone is underweight, normal, overweight or obese, which is what it was designed to do...

also, I don't require weight to dive... with an AL80, until it gets to less than 1500 psi, I am almost perfectly weighted in the water with a normal jacket BCD on, and with my 2 lb plate, I am fine until 500 psi in the same AL80... This is saltwater, no wetsuit (or a 1.5 mil surf top)...

DMWiz
06-18-2010, 10:39
That's why so many people believe BMI is a very inaccurate way to measure someone's fitness level. If your body type does not fit the BMI box then your number will be high.

BMI may work for some people, but definitely not for all of us...

So, one last time BMI may work for some, but it is a horrible way to judge whether someone is underweight, normal, overweight or obese, which is what it was designed to do...


Hum... are you agreeing or disagreeing with me?

If your body type fits the BMI box (Which IMO fits a very large number of people in America) then it is a great guideline to follow.

You and I may not fit that box, but I'm not going to throw out the baby with the bath water because it doesn't work for me, or athletes, or weightlifters and body builders.

I guess what I'm trying to say is this: "As bad as the BMI formula might be as a gauge for everyone, those whose body types it does apply to would greatly benefit from shooting to be in their ideal BMI range instead of clamoring that the formula is not good for everyone therefor no one should follow it!"

Kjay
06-20-2010, 11:33
@LuLu, Hey, I'll go Hiking with you, but a warning, Iraq gets a little warm this time of year.

@et al. hopefully we all learned a little here.

So all in all the answers to my questions:
1. What does all the extra weight (fat) do to a diver?
Answer = besides the health risks, overfat (see I learn quickly) adds bouyancy and associated heat and elevates DCI risks.

2. weight requirements? (is more or less weight required, fat floats?
answer = see number one, Yes, more fat = more lead

3. Health concerns at depth? (well yeah I know at the surface too).
answer = see number one, yes, increased risk for DCI as fat absorbs and off gases nitrogen slower.

@LuLu, i like your style. :)

LeeParrish
06-20-2010, 12:15
@LuLu, i like your style. :)

I would second that :smiley20:

mitsuguy
06-20-2010, 15:35
That's why so many people believe BMI is a very inaccurate way to measure someone's fitness level. If your body type does not fit the BMI box then your number will be high.

BMI may work for some people, but definitely not for all of us...

So, one last time BMI may work for some, but it is a horrible way to judge whether someone is underweight, normal, overweight or obese, which is what it was designed to do...


Hum... are you agreeing or disagreeing with me?

If your body type fits the BMI box (Which IMO fits a very large number of people in America) then it is a great guideline to follow.

You and I may not fit that box, but I'm not going to throw out the baby with the bath water because it doesn't work for me, or athletes, or weightlifters and body builders.

I guess what I'm trying to say is this: "As bad as the BMI formula might be as a gauge for everyone, those whose body types it does apply to would greatly benefit from shooting to be in their ideal BMI range instead of clamoring that the formula is not good for everyone therefor no one should follow it!"

it looks like I agree with you... I'm not sure how many decently built guys it fits though...

its just weird though I guess... a coworker only an inch or so shorter than I weighs a good 30 lbs less than I do, but physically looks fatter than I...

LeeParrish
06-20-2010, 15:45
A lot of appearance is due to body build and weight distribution. Even though someone is the same height/weight the weight can easily be distribute differently. I know with my height/weight I have fairly large legs, which makes me look much thinner than I really am. People will often underestimate my weight, so I must appear to weight less than I actually do. Some folks carry their weight fairly evenly distributed, some more in the middle. Broad shoulders, narrow shoulders, all can contribute to a difference in appearance even though you may have the same height/weight.