Drinking & Diving

[Napoleon_wrasse]

Routine caffeinated coffee contains ~0.71mg of caffeine per ml . Thus, every ml of coffee one drinks will result in the excretion of an extra ~0.71ml of urine. Given an average 8oz serving of coffee, the 240ml of caffeine one imbibes will cause an extra ~17ml of urine to be voided. Doing the math, that's a net gain of ~65ml of fluid.

I was unable to find the data that 0.71 mg of caffeine results in 0.71 ml of urine production from the references you cited. i was also unable to find any dose-response curve showing a linear response in urine output between 0.71 mg to 170 mg of caffeine (not 17mg --> 17ml, i presume it's a typo in your post). I'd be grateful if you could provide this data, thanks.

If you know of any data relating the time course of urine output to a bolus dose of caffeine iv (or intraportally? see http://www.ingentaconnect.com/content/nrc/cjpp/2010/00000088/00000011/art00012 ) I would be interested too. While it may bear some relationship to the caffeine serum half-life it will also be affected by effect site concentrations and time course of caffeine attachment to the adenosine receptor, IMO.

 

[Thalassamania]

Once again, intoxication is not the primary issue here, hydration is.

 

[scjoe]

The French Cocktail and hydration study referenced in post #135 both involved a large quantity of fluid (4-5 cups). How many people are regularly downing that much fruit juice, Gatorade or plain water before a dive?

 

[KWBuddy]

DAN Divers Alert Network : Psychological Issues in Diving III - Schizophrenia, Substance Abuse

From the article: "The American Medical Association (AMA) upper limit of the BAC for driving a vehicle in the United States is 0.05 percent. Surely diving with any alcohol on board would be foolish, considering the alien environment (water) and the complex skills required to follow no decompression procedures."

The statement above demonstrates the unmitigated bias in the article written by Dr. Ernest Campbell and published by DAN.

Aside from merely being poorly worded, it creates a false premise and goes on to base its argument on that falsehood.

The poorly worded part, "surely diving with any alcohol on board would be foolish," is extremely vague at best. Does he mean to say that if I am on an extended vacation on my boat and I have stocked three cases of beer for a month long trip with a crew of four that I would be foolish to scuba dive until that entire stock of alcohol is exhausted? Even if my dive buddy and I had consumed absolutely no alcohol in the previous week? Or does he mean a zero tolerance level for alcohol in the bloodstream? He does not make the statement clear. Anyhow, I'll give him the benefit of the doubt and assume that he is using a medical term "on board" to indicate BAC percentage instead of the nautical term.

However he makes the statement that the AMA's upper limit for driving a vehicle is 0.05 percent BAC, but then cites an "alien environment" and "complex skills" that are required for scuba diving as a basis for his zero tolerance stance. I'm sorry, but to me, the water is not some alien environment. In fact driving a car down an expressway with traffic merging and all the idiots on the road who seem at times to be out to get me, appears to be a much more difficult environment that would require superior reaction time and more complex skills that swimming around on a reef looking at the pretty fish. Seriously.

The complex skills he claims are required for no decompression procedures, make the man sound like he is afraid of diving specifically and the water in general. For a leisurely reef dive the no decompression procedure that I follow is to glance at my computer regularly and see that I have plenty of time left before I have to think about surfacing. It's really no more complex that watching the instrument cluster on your dashboard while driving. Really, Dr. Campbell.

Of course, my computer might fail. But then if I have been paying attention, I should know how much nitrogen I have in my system, how much air I have left and how deep I am. With that information along with my experience and training, I should have a good intuitive understanding how to safely decompress. Especially if I haven't been pushing my limits.

Compare that with the situation one might encounter on the road. Up ahead a hundred feet on the expressway a car in the right hand lane has a blowout and veers into your lane. At expressway speed, your gut reaction may make the difference between life and death. It's not just your life at stake. The lives of your passengers and even other drivers and the passengers in other cars depend on your response in the next second and a half or so.

So, which situation has the potential for greater impact to innocent lives of people around you? In my opinion, driving carries a much greater responsibility.

However, if I get schnockered, go diving and kill myself, I have done something stupid and paid the price for my folly. I really don't expect anyone to feel sorry for me.

--

Bud

 

[KWBuddy]

Once again, intoxication is not the primary issue here, hydration is.

Are we talking about one can of beer three hours before an afternoon dive?

I'm still amazed that we don't have definitive data on dehydration and hydration ... and let's not forget negative pressure breathing diuresis.

I don't mean to belittle anyone's concerns about proper hydration, but I personally would be worried about the alcohol changing the smell of my sweat and attracting the Loch Ness Monster who would swallow me whole much more than the effect of a single beer at lunch on my hydration level.

Especially considering "that we don't have definitive data" on either outcome. On the other hand, if I have a single can of beer and take a hit, I won't blame you for laughing out loud at my sheer foolishness.

--

Bud

 

[Thalassamania]

We know that hydration is a critical factor in avoiding DCS.

We know that drinking alcohol compromises hydration for what is thought to be as long as 24 hours.

We are willing to accept draconian rules about flying after diving when we know better and are able to calculate altitude equivalent dives and notrogen wash out from pure oxygen breathing.

I like beer and rum as much as the next person, but I can not comprehend of why would anyone increase their risk of DCS, to an unknown degree, just to have a bottle of beer or a fruity run drink.

 

[KWBuddy]

We know that hydration is a critical factor in avoiding DCS.

I believe that the only "critical factor" in avoiding dysbarism or decompression illness of any kind is to avoid subjecting yourself to pressure changes too quickly. Anything else is merely a contributing factor.

Heck, I like diving as much as the next person, but I can't comprehend of why would anyone increase their risk of DCS, to a very well known degree, just to have a 190 foot card.

We know that drinking alcohol compromises hydration for what is thought to be as long as 24 hours.

I'm sorry but I don't know that. Could you please cite a reliable study that suggests that a single beer will significantly compromise hydration for a period of 24 hours. I thirst for that knowledge. (Sorry about the pun)

--

Bud

 

[Thalassamania]

I believe that the only "critical factor" in avoiding dysbarism or decompression illness of any kind is to avoid subjecting yourself to pressure changes too quickly. Anything else is merely a contributing factor.

Heck, I like diving as much as the next person, but I can't comprehend of why would anyone increase their risk of DCS, to a very well known degree, just to have a 190 foot card.

First of all you can't get a 190 ft card just because you want one. Second of all you can't make a 190 ft dive with dive by dive approval of the institution's Diving Control Board, and that approval includes not just the plan for the dive but the reason that it must be conducted.

I'm sorry but I don't know that. Could you please cite a reliable study that suggests that a single beer will significantly compromise hydration for a period of 24 hours. I thirst for that knowledge. (Sorry about the pun)

--

Bud

As I have repeatedly stated I know of no reliable studies on the subject. All I have to go on is a rather long ago dinner-time conversation with Chuck Shilling. Would one beer make DCS more likely 23:59 later? Probably not. How about 5 minutes later? How about 2 hours later? The point is that we just do not know. We know less about it than we do about flying after diving and yet we apply rather stringent (and I think unreasoning) rules to flying after diving but we put our head in the sand when it comes to the side effects of alcohol. Rather a strange pass, no?

 

[KWBuddy]

We know that drinking alcohol compromises hydration for what is thought to be as long as 24 hours.

Could you please cite a reliable study that suggests that a single beer will significantly compromise hydration for a period of 24 hours.

As I have repeatedly stated I know of no reliable studies on the subject.

Okay, I think we can agree on that. We really don't know.

My gut feeling is that if alcohol consumption were a critical factor in causing DCS, we would know about it. There are a lot of divers out there who drink and it seems someone would have made the connection by now. There would be reliable studies that documented the link. The evidence would be irrefutable.

For my part, I can't eliminate all risks from my life. I dive fairly conservative profiles to reduce my risks of DCS. If for some reason I feel the need to dive a more extreme profile, then of course I would take extra precautions. But I can always dive tomorrow, or next week so I really have no desire to push the limits and risk taking a hit.

But I'm not going to let fear of the unknown control my life.

Go ahead, Thalassamania, have the last word. . .

--

Bud

 

[Thalassamania]

OK, I'll try.

It is not fear of the unknown, it is being prepared for the unknown that may control the length of your life.

When stuff goes wrong a 30 foot walk in the park can turn into a 200 fsw dash after a rapidly sinking diver (most of the more experienced folks here have had it happen to them at least once). It is not the extreme profile that you planned and prepared for that's gonna hurt you, it's the one that you have to make (perhaps stupidly) on the spur of the millisecond.