Hydration Revisited – Myths Versus Facts

[Add Helium]

The matter of hydration and diving is certainly unresolved. Current practice stresses prehydration and completely ignores the importance of posthydration. Some scientific papers encourage mild to moderate dehydration prior to diving while others warn against it. Some dive experts counsel against drinking coffee or other caffeinated drinks, but there is scientific evidence to the contrary.

This article provides a review of scientific papers regarding the issue of hydration and diving supplying a platform for making educated decisions.

On almost every dive boat I go on, I see people chug water before their dive. However, afterward, they drastically reduce their water consumption. Considering the latest scientific studies, we need to ask ourselves if that is actually good practice. We also need to revisit what happens to our bodies when we are in the water and how immersion and the wearing of protective garments contribute to dehydration. Read more...

 

[dreamdive]

Please let me know if you have any questions. I will be checking in regularly.

Claudia

 

[Freewillow]

VERY interesting....................................

 

[BDSC]

I went to a presentation at the DAN headquarters this past summer and this topic was discussed. One of the things the guy presenting said was that anything you drink in the last 20 minutes or so before your dive does little to hydrate you. I know I always see folks talking a drink just before they suit up and go in thinking it helps.

 

[raftingtigger]

And does over hydrating increase risk for for Immersion Pulmonary Edema (IPE)? That is another important question.

 

[AdivingBel]

I don't expressly try to hydrate when I'm diving. I drink when I'm thirsty. I assume if I'm not ill or have another medical issue going on my body is sending the correct signals. Am I missing something?

 

[boulderjohn]

I don't expressly try to hydrate when I'm diving. I drink when I'm thirsty. I assume if I'm not ill or have another medical issue going on my body is sending the correct signals. Am I missing something?

I think the purpose of the article is to address a notion held by many that dehydration is a major cause of DCS and that divers need to be seriously hydrated prior to a dive. There are people who take that idea to an extreme.

 

[Lorenzoid]

I don't expressly try to hydrate when I'm diving. I drink when I'm thirsty. I assume if I'm not ill or have another medical issue going on my body is sending the correct signals. Am I missing something?

My understanding is that the sense of thirst lags behind the body's need for water, so by the time you feel thirsty you are already insufficiently hydrated. I don't know whether that's exaggeration/myth. I try to drink water a little at a time throughout the hours preceding a dive so that by the time I get in the water I don't feel thirsty. However, I suppose I'm "guilty" of taking a swig of water just before the dive, in the belief it's going to provide some extra measure of insurance.

 

[AdivingBel]

My understanding is that the sense of thirst lags behind the body's need for water, so by the time you feel thirsty you are already insufficiently hydrated. I don't know whether that's exaggeration/myth. I try to drink water a little at a time throughout the hours preceding a dive so that by the time I get in the water I don't feel thirsty. However, I suppose I'm "guilty" of taking a swig of water just before the dive, in the belief it's going to provide some extra measure of insurance.

I'll buy that...By the time I drag gear and tanks around and setup for the dive, I'm "thirsty" (hopefully not dehydrated). I'll generally grab a cup of water right before the dive so I don't start out with "cotton mouth" as opposed to "trying to hydrate." Maybe that's the same thing, just an interpretation of body signals.

 

[descent]

The normal humidity at the bottom of a healthy human lung should be pretty high -- nearly 100%. The amount of water vapor inside a clean, topped off AL80 should be nearly zero, if the water traps in the compressor room were working correctly.

When we dive, we suck the dry air in. Huge amounts of moisture leave the moist lung tissue into the inhaled dry gas. Our lungs act as humidifiers.

Then we blow the humidified gas out into the water column and inhale some more dry air.

For me, the wonder is not that a few people get IPE. The amazing thing to me is that everybody doesn't get it.