So what do we think about hydration and DCS now...?

[danvolker]

If a person gets dehydrated, they will typically begin cramping ( one of the symptoms).
If you begin cramping on ascent, your bloodflow is massively interfered with in the cramped muscles, allowing the potential for bubbling to change a great deal----which I would suggest is a real multiplier for the threat of DCS.

For most divers, where any real exercise is practically a joke ( meaning little if any), the need is for pure water, not a sports drink.
However, a good sports drink would have potassium and half as much sodium plus magnesium ( electrolytes), and it would have no sugar--so this is not going to hurt anyone, and it may help some divers that did push their muscles a lot, via the magnesium which helps relax the muscles after each contraction--avoiding cramps.

Sugar, as found in high concentrations in tasty but near poisonous drinks like Coke ( which divers have a tendency to favor--almost cultural), promotes Advanced Glycation End Products ( A.G.E.) -- which means an "inflammation response" where sugar globules form on muscle, tendon, and even linings of blood-vessels, and create inflammation sites. Long term, this creates such obvious complications as Arthritis and Heart Disease--and is probably involved in causing more illnesses on the American population than any other single cause...this cause being Sugar....Coke just happens to be a great example of a "sugar Delivery vehicle" that the population is easily compelled to consume, and then is addicted to.

As cost is far less than for healthy sports drinks, the ignorant and addicted have a great love for this drink.....and so Dive boats tend to buy it in mass quantity, and they assist with the delivery mechanism, and Dopamine addiction---ultimately the Coke adds to the potential for increasing the chances of DCS via the inflammation response.

 

[tajkd]

If a person gets dehydrated, they will typically begin cramping ( one of the symptoms).
If you begin cramping on ascent, your bloodflow is massively interfered with in the cramped muscles, allowing the potential for bubbling to change a great deal----which I would suggest is a real multiplier for the threat of DCS.

For most divers, where any real exercise is practically a joke ( meaning little if any), the need is for pure water, not a sports drink.
However, a good sports drink would have potassium and half as much sodium plus magnesium ( electrolytes), and it would have no sugar--so this is not going to hurt anyone, and it may help some divers that did push their muscles a lot, via the magnesium which helps relax the muscles after each contraction--avoiding cramps.

Sugar, as found in high concentrations in tasty but near poisonous drinks like Coke ( which divers have a tendency to favor--almost cultural), promotes Advanced Glycation End Products ( A.G.E.) -- which means an "inflammation response" where sugar globules form on muscle, tendon, and even linings of blood-vessels, and create inflammation sites. Long term, this creates such obvious complications as Arthritis and Heart Disease--and is probably involved in causing more illnesses on the American population than any other single cause...this cause being Sugar....Coke just happens to be a great example of a "sugar Delivery vehicle" that the population is easily compelled to consume, and then is addicted to.

As cost is far less than for healthy sports drinks, the ignorant and addicted have a great love for this drink.....and so Dive boats tend to buy it in mass quantity, and they assist with the delivery mechanism, and Dopamine addiction---ultimately the Coke adds to the potential for increasing the chances of DCS via the inflammation response.

I apologize in advance. As a researcher, I'm confounded by unsupported claims in diving, especially regarding DCS or other diving ailments. I'm sure there are studies relating cramps and DCS, sugar and DCS, etc. Perhaps you can share the studies so I can become better informed.

 

[danvolker]

I apologize in advance. As a researcher, I'm confounded by unsupported claims in diving, especially regarding DCS or other diving ailments. I'm sure there are studies relating cramps and DCS, sugar and DCS, etc. Perhaps you can share the studies so I can become better informed.

Not to be argumentative....but the Research system, peer Review, and utility of the Journals "used to " function nicely with the implications you just noted.

However, in the last decade, the big corporations have been essentially "Buying" studies to PROVE whatever is good for their products and services----Misinformation is so chronic it has even badly infected the system once so revered by the scientific community. Big Pharma has made trillions by warping the peer review process, and the desperate need for FUNDING has led a great many researchers to work and support projects they know to be functionally and morally defective, and that many paths that are clearly good for the masses--would be bad for most corporations and so economically such research is unsupported, and harder and harder to find.

Coke likes to say that " a Calorie is a Calorie", even though the good research ( the fraction in Nutrition and supplement industry) proves quite conclusively that a fructose calorie is very different in the metabolic response than a protein or a fat calorie. The cigarette / tobacco industry spent a fortune in the 50's, 60's and 70's on RESEARCH that would create DOUBT that a real correlation existed between lung cancer and smoking....this may well have become the "Playbook" by which most major corporations selling profitable but harmful products today, live by, in assigning large scientific grants to create misinformation, and disinformation, that will protect their profitability in the present and future.

My point is.....YOU as a researcher, will run into far more SUPPORTED CLAIMS that are in fact, mis-informational in effect, the moment your researching turns away from a "win" for everyone, and begins relating to an outcome that could be effecting trillions of dollars.....There SHOULD be a massive amount of research showing A.G.E is a culprit in a vast number of ailments today--however, this acceptance would lead to simple Nutritional CURES....which would cost Big Pharma Trillions in symptomatic Treatment of illnesses....not to mention the billions it would cost companies like Coke, and whole industries like Fast Food. This is an industry that should have been absolutely destroyed by Research and Science, but the system was perverted, and now science has become it's henchman.

You can research A.G.E. and Diabetes, and find reams of material that would explain the obvious complications and paths to move in....but the MONEY spent by Big Pharma speaks to keeping this as discarded and largely irrelevant.
YOU can do the research on the effects of poor bloodflow --poor perfusion, as it related to DCS....you should not require me to do this for you, and you should not require me to PROVE the OBVIOUS CONNECTIONS WHEN YOU should be very capable of doing this YOURSELF.
I read research publications frequently.....but not for a living. If this IS your job, you should have come across so many more than I, that really it should be YOU offering the cites here, rather than asking me for them!!!

P.S.
I am absolutely NOT trying to be antagonistic to you on this.....this is not against you or Research.. I love Research....this is a NECESSARY "Tilt against the Windmill " .... one I would hope you and others would take interest in as well !!!

 

[tajkd]

Not to be argumentative....but the Research system, peer Review, and utility of the Journals "used to " function nicely with the implications you just noted.

However, in the last decade, the big corporations have been essentially "Buying" studies to PROVE whatever is good for their products and services----Misinformation is so chronic it has even badly infected the system once so revered by the scientific community. Big Pharma has made trillions by warping the peer review process, and the desperate need for FUNDING has led a great many researchers to work and support projects they know to be functionally and morally defective, and that many paths that are clearly good for the masses--would be bad for most corporations and so economically such research is unsupported, and harder and harder to find.

Coke likes to say that " a Calorie is a Calorie", even though the good research ( the fraction in Nutrition and supplement industry) proves quite conclusively that a fructose calorie is very different in the metabolic response than a protein or a fat calorie. The cigarette / tobacco industry spent a fortune in the 50's, 60's and 70's on RESEARCH that would create DOUBT that a real correlation existed between lung cancer and smoking....this may well have become the "Playbook" by which most major corporations selling profitable but harmful products today, live by, in assigning large scientific grants to create misinformation, and disinformation, that will protect their profitability in the present and future.

My point is.....YOU as a researcher, will run into far more SUPPORTED CLAIMS that are in fact, mis-informational in effect, the moment your researching turns away from a "win" for everyone, and begins relating to an outcome that could be effecting trillions of dollars.....There SHOULD be a massive amount of research showing A.G.E is a culprit in a vast number of ailments today--however, this acceptance would lead to simple Nutritional CURES....which would cost Big Pharma Trillions in symptomatic Treatment of illnesses....not to mention the billions it would cost companies like Coke, and whole industries like Fast Food. This is an industry that should have been absolutely destroyed by Research and Science, but the system was perverted, and now science has become it's henchman.

You can research A.G.E. and Diabetes, and find reams of material that would explain the obvious complications and paths to move in....but the MONEY spent by Big Pharma speaks to keeping this as discarded and largely irrelevant.
YOU can do the research on the effects of poor bloodflow --poor perfusion, as it related to DCS....you should not require me to do this for you, and you should not require me to PROVE the OBVIOUS CONNECTIONS WHEN YOU should be very capable of doing this YOURSELF.
I read research publications frequently.....but not for a living. If this IS your job, you should have come across so many more than I, that really it should be YOU offering the cites here, rather than asking me for them!!!

P.S.
I am absolutely NOT trying to be antagonistic to you on this.....this is not against you or Research.. I love Research....this is a NECESSARY "Tilt against the Windmill " .... one I would hope you and others would take interest in as well !!!

exactly as I thought. You are correct, I do normally read the actual research when available. Often it is difficult to get, as many folks just print their (or the authors) opinion of the data. In this case, it appears that there are no studies linking sugar intake and DCS (many implications for diabetes though) nor are there studies linking cramps and DCS. The obvious connection is a little hard to prove, eh?

 

[danvolker]

More on the whole issue of people here making claims that are "supported" or not....and the need for common sense to be utilized--sometimes even more than the current research...

[h=2]Research Funded by the Beverage Industry Often Finds No Connection Between Sugary Beverages and Obesity[/h]

Researchers reviewed 17 papers (with 18 conclusions) and found that 11 of them supported a significant link between sugar-sweetened beverages and weight gain or obesity. They then reviewed them based on whether or not the authors reported any conflicts of interest… and here's where things got interesting.
Among studies with no conflict of interest, 10 out of 12 supported the association between sugar-sweetened beverages and obesity or weight gain. Among studies with industry support, 5 out of 6 found no association.
In other words, in studies without industry support, 83 percent linked sugary beverages with weight gain. But in studies with industry support, 83 percent found no link at all.
It's a striking disparity and a likely reason why some research seems to fly in the face of common sense and show no connection between such drinks and obesity. Researchers noted:

"Those reviews with conflicts of interest were five times more likely to present a conclusion of no positive association than those without them.
​

…Our results confirm the hypothesis that authors of systematic reviews may draw their conclusions in ways consistent with their sponsors' interests."
​

 

[bvanant]

My understanding is based on a few published papers (Br J Sports Med. 2009 Mar;43(3):224-8. doi: 10.1136/bjsm.2007.043240. Epub 2008 Feb 28.[h=1]Preventive effect of pre-dive hydration on bubble formation in divers. Gempp E1, Blatteau JE, Pontier JM, Balestra C, Louge P.), suggesting that a 340 mOsm drink led to "Pre-dive oral hydration decreases circulatory bubbles, thus offering a relatively easy means of reducing decompression sickness risk. The prehydration condition allowed attenuation of dehydration and prevention of hypovolaemia induced by the diving session.Hydration and diving did not change plasma surface tension in this study."[/h]This was a drink that contained glucose as well as salts (I don't have full access at home), but this is an interesting paper with little mechanism support that I can find.

As for obesity and sugary drinks, there are at least 200 peer reviewed papers in the PUBMED literature and all but a few suggest that the link is indeed true. From the AGE standpoint, I don't think it is clear yet on the relative rates and relative "badness" of glucose vs. fructose glycation products and in fact it it just becoming possible to distinguish the two different forms of glycated proteins.
Bill

 

[The Kraken]

Personally, I think many divers have a tendency to "over hydrate". I'm not saying this is a bad thing, more than necessary water is not a bad thing compared to too little. It's just that I see people CONSTANTLY "hydrating".

The body can use only so much water, the rest is discharged as perspiratin and urine.

My philosophy is to stay properly hydrated, that is consume the amount of water that the medecial sciences recommend for your particular age, weight, activity, etc.

Safe dives . . . . . .
. . . , safer ascents!

the K

 

[dreamdive]

For those interested, I put additional reference on here on the topic of hydration. At the end of the list, I posted the link on the article on Immersion Pulmonary Edema that I wrote. The excerpt related to hydration is posted here for convenience.

A summary note on hydration and DCS is given at the very end.

DCS - Hydration
Blatteau JE, et al – Hemodynamic changes induced by submaximal exercise before a dive and itsconsequences on bubble formation
Br. J. Sport Med 2007, 41:375-9
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://bjsportmed.com/content/41/6/375.short[/COLOR]
Blatteau JE, [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Gempp E[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Balestra C[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Mets T[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Germonpre P [/COLOR]– Predive sauna and venous gas bubbles
upon decompression from 400 kPa
Aviat Space Environ Med 2008; 79: 1100-5
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://www.ingentaconnect.com/content/asma/asem/2008/00000079/00000012/art00005[/COLOR]
[COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Gempp E[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Blatteau JE[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Pontier JM[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Balestra C[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Louge P [/COLOR]– Preventive effect of pre-dive hydration onbubble formation in divers
Br. J. Sport Med 2009; 43:224-228
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://bjsm.bmj.com/content/43/3/224.short[/COLOR]
Castagna O, [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Brisswalter J[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Vallee N[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Blatteau JE [/COLOR]- Endurance exercise immediately before sea divingdecreases bubble formation
Eur J Appl Physiol 2011; 111: 1047-54
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://link.springer.com/article/10.1007%2Fs00421-010-1723-0[/COLOR]
ConkinJ, et al – Effect of hydration on nitrogen washout in human subjects.Houston, TX: NASA, Johnson Space Center; 1983: 1-20
Fahlman A, Dromsky DM – Dehydration effects on the risk of severe decompression sickness in a
swine model
Aviat Space Environ Med 2006; 77:No 2
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://www.ingentaconnect.com/content/asma/asem/2006/00000077/00000002/art00002[/COLOR]
Gempp E, [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Blatteau JE[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Pontier JM[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Balestra C[/COLOR], [COLOR=rgb(14.901960%, 14.901960%, 14.901960%)]Louge P [/COLOR]- Preventive Effect of Pre-Dive Hydration onbubble Formation in divers.
British Journal of Sports Medicine 2009; 43: 224-228
[COLOR=rgb(0.000000%, 0.000000%, 100.000000%)]http://bjsm.bmj.com/content/43/3/224.short



[/COLOR]IPE ? Immersion Pulmonary Edema | Add Helium


A possible explanation might be from over-hydration. When we immerse in water up to our necks, we shunt about 700 ml of blood from the periphery to the central core, i.e. the central vasculature. When blood gets shunted suddenly to the core, the heart and great vessels have to accommodate this additional volume. Usually, vessels will attempt to dilate. Increasing the diameter of a vessel will result in a decrease in pressure. Without this dilation, the pressure remains high.
Prior to an immersion, our vasculature might alreadybe “full” when well hydrated. Although adequately hydrated on the surface, with immersion we might suddenly become over-hydrated. Typically our hearts are sensing this excessive volume and will signal the kidneys to get rid of water and salt to decrease the volume. The signaling mechanism is via hormones of increased Atrionatiuretic Peptide (ANP) and decreased Vasopressin. The results are not immediate, as our kidneys need a little time to complete the task.

Considerations for the Prevention of DCS ?Do?s? and ?Dont?s? | Add Helium
Hydration

Do: Re-hydrate immediately after the dive. It is during the dive, where we lost a lot of our hydration and need to replenish!
Don’t: Aggressively hydrate before the dive. Overhydration puts a lot of strain on your heart and actually may put you at risk for developing pulmonary edema. Obviously, if you have a stomach bug and become dehydrated, you need to replenish until you get to euvolemia (normal body fluid volume) again. If you were binge drinking the night before, (another don’t, by the way), you need to replenish.
Don’t: Hit the bar and load up on alcoholic beverages after the dive. You need to re-hydrate your body first! Be responsible with your alcohol intake when diving! Too much alcohol will not only give you a hangover the next day, but will be dehydrating, as well. Your liver may not metabolize too much alcohol in time before jumping in the water the next day! You basically are diving while intoxicated!

 

[MaxBottomtime]

I've seen people on boat gulp water like it was air, telling me they don't want to get dehydrated. Until you've been out in the Sun and can no longer sweat or even get enough spit to moisten your lips you have not been dehydrated.
I've been doing a personal study by drinking way too much Diet Pepsi over the past two decades, including several in the hours leading up to a dive. In spite of my caffeine intake and several hundred deep air dives over the past 25 years I haven't been able to get bent. I'll let you know if I ever succeed.

 

[danvolker]

I've seen people on boat gulp water like it was air, telling me they don't want to get dehydrated. Until you've been out in the Sun and can no longer sweat or even get enough spit to moisten your lips you have not been dehydrated.
I've been doing a personal study by drinking way too much Diet Pepsi over the past two decades, including several in the hours leading up to a dive. In spite of my caffeine intake and several hundred deep air dives over the past 25 years I haven't been able to get bent. I'll let you know if I ever succeed.

I don't see hydration levels as hugely significant, in the ways that they vary from diver to diver on most charter boats...."Except" when the group finds itself in a un-planned, high exertion scenario--and this relates to whether or not they will cramp or come close to it. The cramping or shunting of blood, would most likely have a real effect on the potential for DCS to occur.

On the other hand, fitness will be far more important for the individuals in such a group, than how much water, or how much soda, or how much of the perfect sports drink they had prior to jumping in to the water---as with high fitness, those in the intact group will not be working that hard--and those with low fitness will have little headroom before the higher workload could cause cramping or bloodflow issues.

Even on an hour long anaerobic effort of a racing cyclist on a time trial bike ( running at around 90% or max heart rate) , it makes little or no difference whether you use water or the best sports drink ( as a racer).....this would relate to exertion levels far beyond anything we could imagine on any kind of dive.....Switch to a century ride--one hundred miles, in 4 or 5 hours, and the optimal sports drinks become massively significant in the 2nd hour and thereafter ( now you are talking low aerobic Heart rate levels, more like 70% of max).

I see this being relevant to a group on a liveaboard, doing 5 or 6 dives in a day--and potentially exposed to lots of heat while on the surface, and less than optimal nutrition for the dive day----the typical divers with have enough stored glycogen for the first or second dive, and then for the 3rd to 6th dives, how well their muscles feel and function, will be impacted by good or bad choices in food and drink....High Sugar choices will work against them and help to cause inflammation and impair uptake of necessary nutrients by muscles that have been depleted of glycogen -- by multiple dive workloads.......Diet Soda will not be helping nearly as much as an ideal sports drink ( with complex carb, protein, ideal electrolyte mix and no or very low sugar)......
As to heart rates during dives, the dive groups would rarely be over 65% of their max heart rates on any parts of the dives, but the issue is what exertion there is on the dives, depletes muscle glycogen, and if not replenished prior to later dives, this can cause cramping.

And....instead of Sports Drinks, Ideal healthy food between dives and plenty of water to restore what they lost would work just as well as sports drinks for the liveaboard group....( not over-hydration).