Could scuba diving be bad for people with high blood-pressure?

[diver_doug]

Specifically what I mean is this: it is definitely the case that you are able to absorb stuff through your skin, and sea-water contains a tremendous amount of salt...so is it possible for a diver with high blood-pressure to absorb enough salt through his/her skin to cause hypertension issues? I don't have high blood-pressure, just something I'm curious about.

 

[soltari675]

Actually, if I am remembering correctly from biology classes, the water in your body will try to get out to try and equalize. The salt doesn't pass, unless you drink it which is just gross. Water is what moves. So you might get dry skin or dehydrated, but you won't take in the salt. I could be wrong. Just what I remember.

 

[--tom--]

Not if you are diving in the Great Lakes

 

[Charlie99]

The real cardiac danger is overexertion. This is particularly true of divers are some particular style of high blood pressure control medicines.

I don't have much info on transfer of salt into the body, but I'm almost certain it is negligible. The body fluids are around 0.9% salt. The ocean is about 3.5%. I think that the more significant effect of very prolonged exposure is that the chemistry of the body will move towards the higher salt content of the ocean, but by losing water, not by absorbing salt. That's what soltari675 means when he says "he water in your body will try to get out to try and equalize"

 

[Guba]

I have had hypertension for years, but it is controlled with weight reduction and meds. About the only danger that I have is one of those meds is a diuretic, so on dive days I generally use a combination of meds that eliminates that prescription (done with the full approval of my doc, of course). This helps keep my blood volume high and decreases the risk of DCS. One thing I will attest to, try to stay off beta-blocker meds if you can. I was prescribed that and found right away that it GREATLY limited my ability to exert myself, which could be dangerous underwater in a clinch (also threw major kinks in my plans for upcoming triathlons). I again consulted my physician, and we worked out another strategy.
For me, diving with treated hypertension isn't a problem. My advice to anyone affected is to just be upfront with your doctor and be as informed as you can be.

 

[TSandM]

One of the amazing things about skin is how good a barrier it is. After all, it's designed to keep you wet inside in a very arid environment! Water, as a small molecule, passes almost all barriers, but salt does not. Your hands will get wrinkled from being a long time in the water, but you will not absorb any significant amount of salt.

The big concern for hypertensive divers is probably immersion pulmonary edema, which is unpredictable, associated with hypertension, and can be fatal. But it isn't related to absorption of salt.

 

[Kingpatzer]

The bigger issue is the loss of endothelial function that accompanies diving, and which is exacerbated by nitrox use.

 

[gcs118]

The big concern for hypertensive divers is probably immersion pulmonary edema, which is unpredictable, associated with hypertension, and can be fatal. But it isn't related to absorption of salt.

The bigger issue is the loss of endothelial function that accompanies diving, and which is exacerbated by nitrox use.

In lay terms, these two concerns would be...

 

[Kingpatzer]

Endothelial function is hte ability of your blood vessels to contract and expand. Recent studies have shown that divers suffer a measurable loss of endothelial function, and that loss is exacerbated by using nitrox. It's not as if your blood vessels start being unable to expand and contract, but they start being slower at it, and doing it less.

Since the blood vesssels' control blood pressure through contracting and dilating, and because the endothelium plays a major role in that activity, loss of endothelial function can be a problem for folks with hypertension or other circulatory issues.

 

[Searcaigh]

As far as I am aware salt is excreted through the skin i.e sweat, and it is a one-way system, no salt absorbed