Anyone use the heart rate monitor on their sol ?

[beaverdivers]

Snow, we finally got some.

It's a POWDER day.

Get back to you on this question after the snow.

[GrumpyOldGuy]

I found a DAN article with references relevant to this:

Divers Alert Network

"Timing of exercise during diving

Physical activity during the dive also has a direct impact on decompression safety.4,5,6,9 Exercise during the compression and bottom phase increases inert gas uptake, effectively increasing the subsequent decompression obligation of any exposure. It is important to remember that dive tables and computers estimate inert gas uptake, they never know reality. On the flipside, light exercise during the decompression phase (including safety or decompression stops) increases inert gas elimination and reduces risk. The caveat regarding exercise during decompression is that more is not always better. Too much or too intense exercise during the decompression phase can stimulate bubble formation, thus inhibiting inert gas elimination and increasing decompression risk."

Interesting Article (not a peer reviewed scientific journal, but still a worthwhile read). However the very next paragraph in the article states

"We do not yet have sufficient data to quantify the difference between beneficial and potentially harmful exercise. Understanding the various issues and applying common sense confer the best protection. Most important is that moderate time-depth profiles are your best defense. "

So basically they are saying exercise can effect decompression (which I am not contesting) , but we don't know enough to predict the effect. This is why I have difficulty in putting much weight in a heart rate monitor to "correct" the decompression calculations.

[mathauck0814]

Interesting Article (not a peer reviewed scientific journal, but still a worthwhile read). However the very next paragraph in the article states

"We do not yet have sufficient data to quantify the difference between beneficial and potentially harmful exercise. Understanding the various issues and applying common sense confer the best protection. Most important is that moderate time-depth profiles are your best defense. "

So basically they are saying exercise can effect decompression (which I am not contesting) , but we don't know enough to predict the effect. This is why I have difficulty in putting much weight in a heart rate monitor to "correct" the decompression calculations.

We DO know that temperature has an effect on solubility based on Henry's law. When the temperature rises the capacity for gas in solution is reduced and bubbles form for subsequent release (think heating cold tap water on the stove, before it boils you see bubbles forming along the bottom surface of the pot). So it does stand to reason that there's SOME impact if you can tie a rise in body temperature to the elevated heart rate. When it comes to diving, I just don't think you're going to get your internal temperature to rise to the level that you would say exercising in hot sun. So just how "hot" can you get underwater is the question that hasn't been answered.

The DAN article alludes to something I remember from some of the training I did where they didn't want us to haul our equipment after long decompression dives because activity can cause bubble formation (presumably through increasing heat locally).

So again, I think there's likely a possibility that top-side, after a dive, you can effect enough of a change on your body through exertion where bubble formation can be an issue - not so underwater. I don't believe that as heart monitor attached to your computer can give you any more accurate a plan than any other computer. To my ears it's another gimmick.

Scubapro should make good on its promise to bring trimix support to this computer and worry less about the gadgetry. It's not much surprise that beaverdivers gets aggressive about this given her profile states she's a "platinum scubapro dealer". I've got no dog in this fight, just curious how the theory would work...

[Hatul]

There are a few scientific articles referenced in that DAN article and some others I found on the Google search if someone wants to devote the time to fetch them. I suspect the modeling of the effect of increased cardiac output and ventilation with exercise that Uwatec is using is based on some scientific study, just as the tissue model they use is. I doubt they're making up a model out of thin air. I bet if someone requests they would provide the references.

Personally I have the workload turned on in my Sol but at a decreased sensitivity-- you can change the sensitivity to the workload in the options. The reason is I'm concerned the HR monitor may have some artifact that can screw up the decompression algorithm. But in practice the HR monitor is quite reliable in my experience diving with a wetsuit.

I mentioned earlier a report from a drysuit diver whose monitor double-counted his heart rate, and his computer went haywire. He attributed this to his drysuit and sweating.

Adam

[gotair?]

Glad to see my post started up a good discusion. I have another question that maybe someone can answer. If I am at a decompression stop and a great white swims by me, I 'm sure that will increase my heart rate and exertion but will that increase my decompression time using the heart rate moniter/sol? Looking at the DAN articles I would think it should.

Thanks for all the previous replies

[mathauck0814]

Glad to see my post started up a good discusion. I have another question that maybe someone can answer. If I am at a decompression stop and a great white swims by me, I 'm sure that will increase my heart rate and exertion but will that increase my decompression time using the heart rate moniter/sol? Looking at the DAN articles I would think it should.

Thanks for all the previous replies

Not to any degree that would matter. The larger concern would be your increased heartrate and the potentially high PPO2 that you're breathing putting you at a higher risk of toxing. Remember the reason that 1.6 is acceptable for decompression is because you're theoretically "at rest". I don't think that such an event would substantially change the dive profile at all (which has been my assertion all along), but it might be one of those events for which you might plan air breaks into your contingency...

[highflier]

Glad to see my post started up a good discusion. I have another question that maybe someone can answer. If I am at a decompression stop and a great white swims by me, I 'm sure that will increase my heart rate and exertion but will that increase my decompression time using the heart rate moniter/sol? Looking at the DAN articles I would think it should.

Thanks for all the previous replies

Seeing a Large Great white would reduce my deco time to 0. On the boat I would go without waiting. From there I might be heading to the nearest Deco chamber where I hopefully will make a full recovery.

On the other hand if it did not reduce my deco time to 0. I might be on the way to a mortition, which maybe trying to determain if there is enough of me left to have a open or closed casket funural.

Highflier