Blood pressure?

[Wozzer]

When you descend you enter a higher pressure environment, wouldn't it then follow that in order to maintain perfusion, your BP would also have to go up? Does this possibly pose a hazard to folks who are sensitive to high BP (aneurysms, aortic dissections, strokes etc)? Is it a cause of concern for otherwise healthy folks (ie, increasing the risk of atherosclerotic dz similar to primary HTN)?

 

[Soundtracklover]

Blood pressure is affected while diving and your BP will most likely rise under the water. If you go for PADI open water certification or even a discover diving class, PADI requires you to have a medical statement signed by your doctor clearing you to dive.

I have high blood pressure and am being treated for it with 10mg of Lisinopril. My BP medicine is an ACE inhibitor which has less side-effects under water. The main side effect is a cough - which luckily I did not have while diving.

Only you and your doctor know if you are well enough to dive. But don't let high BP scare you away. I'm glad I didn't let it scare me away. I had such a wonderful time diving.

Are you being treated?

 

[Rick Inman]

Actually, one day right after a dive, I checked my BP in one of those grocery store BP things and it said that mine was WAY down - from 148 (my normal) to 127! I went and bought a bp cuff and started checking it before and after the dive. Sure enough, my BP drops significantly after diving, and stays that way for up to 48 hours.

I went to my doctor and reported my findings. He said, "Then by all means, I prescribe lots of scuba diving for you."

My wife was right there when he said it.

I could have kissed him.

 

[Wozzer]

Sorry I actually don't have high blood pressure myself, this is more of an academic question so I can give advice to folks who do. I wonder if having low BP afterwards is a reflex after diving because your peripheral resistance goes down (blood vessels relax) while diving (because it has to in order to keep blow flow going to organs that are now under pressure). I'd love to write a script for diving QOD haha, diving definitely is awesome!

 

[scuba70]

If you go for PADI open water certification or even a discover diving class, PADI requires you to have a medical statement signed by your doctor clearing you to dive.

Actually PADI doesn't require you to get a signed medical statement as long as you don't have to answer yes to any of the medical questions. If you do answer yes, then you need to bring a signed form from a physician.

 

[Charlie99]

It seems that the original poster is operating under a basic misconception about what sort of pressure is needed to pump the blood around the body when submerged at depth. Even though I may be at 66' or 3 atmospheres absolute pressure, the relative pressure needed to pump blood around my body stays pretty much the same. Since my heart is already at 66' or 3ata of pressure, it only needs to add more or less the same pressure to the blood to get it to circulate around the body that it does while on the surface. To put it another way, if I were to measure my absolute BP (or pressure referenced to the surface pressure), it would be totally off the chart high, but if measured compared to the local ambient pressure, it would be close to normal. The blood vessels and heart are only affected by the difference between BP and the ambient pressure.

There may be other, small effects that either raise or lower the BP, but to the first approximation, it is independent of depth.

Charlie Allen

 

[Wozzer]

It seems that the original poster is operating under a basic misconception about what sort of pressure is needed to pump the blood around the body when submerged at depth. Even though I may be at 66' or 3 atmospheres absolute pressure, the relative pressure needed to pump blood around my body stays pretty much the same. Since my heart is already at 66' or 3ata of pressure, it only needs to add more or less the same pressure to the blood to get it to circulate around the body that it does while on the surface. To put it another way, if I were to measure my absolute BP (or pressure referenced to the surface pressure), it would be totally off the chart high, but if measured compared to the local ambient pressure, it would be close to normal. The blood vessels and heart are only affected by the difference between BP and the ambient pressure.

There may be other, small effects that either raise or lower the BP, but to the first approximation, it is independent of depth.

Charlie Allen

Excellent point, don't know why I had that thinking error - I was considering the periphery and central compartments as "separate" when of course they're both in the same high pressure environment. Guess that clears that up

 

[MeiLing]

Actually, one day right after a dive, I checked my BP in one of those grocery store BP things and it said that mine was WAY down - from 148 (my normal) to 127! I went and bought a bp cuff and started checking it before and after the dive. Sure enough, my BP drops significantly after diving, and stays that way for up to 48 hours.

I went to my doctor and reported my findings. He said, "Then by all means, I prescribe lots of scuba diving for you."

My wife was right there when he said it.

I could have kissed him.

That explains why my blood pressure was well within the normal range at one Dr.s on Monday and pre-hypertensive at another's on Friday. We usually dive Sunday.

I guess I just need more dive therapy!

 

[Dr Deco]

Hello woozer :

Blood Pressure Underwater

Yours is a frequently-asked question. As indicated above, blood pressure [BP] is independent of the external pressure as long as the pressure is applied evenly. Hydrostatic is the easiest way to apply pressure evenly.

Another way in which this question is asked refers to a cut. “If I cut myself underwater, will the water rush into my body through the cut?” No, it will not. Alternatively, we hear, “If I cut myself underwater, will the blood squirt out through the cut?” Again, no, it will not.:blinking:

BP On the Surface

Postexercise, some individuals do experience a drop in BP. The increase in blood flow to muscles continues following physicl activity, and it is termed ‘post-exercise hyperemia.” This muscle perfusion coupled with reduced heart rate leads to a drop in BP for a while.

Dr Deco :doctor:



The next class in Decompression Physiology for 2007 is August 18-19. :1book:
This class is at the USC campus in Los Angeles.
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[crpntr133]

So if anything those that have low BP might wish to be careful after a dive?