Heart Rate monitor for Precise Decompression

[1_T_Submariner]

The new UWATEC Galileo ad says it features a "heart rate monitor for Precise decompression calculations."

I just have never seen anyone talk about this. Is it something new or a gimmick?

Thanks in advance for any insight.

 

[Charlie99]

I don't have any direct knowledge of this particular device, but it sounds similar to the adjustment that some air-integrated Uwatec computers do. The theory is that if you work hard at depth that you will have increased blood flow, which in turn effectively lowers the halftime of some tissues. Some AI Uwatec computers detect high air consumption and/or changed breathing patterns and use that to infer the divers workload and adjust the assumed N2 absorption in the various compartments.

My guess is that this new computer simply does the same thing, but by measuring change in heart rate.

Charlie Allen

 

[Hoosier]

I don't have any direct knowledge of this particular device, but it sounds similar to the adjustment that some air-integrated Uwatec computers do. The theory is that if you work hard at depth that you will have increased blood flow, which in turn effectively lowers the halftime of some tissues. Some AI Uwatec computers detect high air consumption and/or changed breathing patterns and use that to infer the divers workload and adjust the assumed N2 absorption in the various compartments.

Charlie Allen

Really I have never heard that AI function (monitoring SAC) will affect any deco/bottom time. Even, we can't see the SAC rate during the dives. (Please let me know if I am wrong here).

As I recall, there is a review that heart monitoring function lost a signal during the review dive. If then, what is point?

 

[DanLVolker]

Really I have never heard that AI function (monitoring SAC) will affect any deco/bottom time. Even, we can't see the SAC rate during the dives. (Please let me know if I am wrong here).

As I recall, there is a review that heart monitoring function lost a signal during the review dive. If then, what is point?

Perhaps if this computer had your pre-tested VO2 max entered in, and you were on tables adjusted for your VO2 max ( assuming correlation from peripherol adaptations to cardio vascualr training ), then this would be highly functional...as it is, I see it as a nice toy, and maybe a good direction, but it will still need to evolve alot before it can do what the marketing is bound to indicate.
Dan V

 

[Hoosier]

I haven't read through their manual though.

Based on my understanding, any computers having AI function in the market soley show a SAC rate after the dive. It doesn't affect any deco/bottom time calculation.

In the same logic, the new feature, heart monitoring, only shows the workload over time.

That's what I understand.


Please let me know if anyone has any direct experience.

 

[Charlie99]

The Aladin® Air Z O2 uses the decompression calculation model known as the ZH-L8 ADT. This model uses
eight compartments or “tissue“ groups with nominal half time periods from 5 to 640 minutes. This model
differs considerably from other models by its consideration of the following additional physiological
processes:
1.Blood perfusion to the body‘s organs is not constant. Skin and muscle tissues are in particular subject
to changes in blood perfusion, depending on temperature and workload. Changes in blood perfusion to
these organs change their nitrogen saturation tolerance. The model used by the Aladin® Air Z O2 takes
these effects into account and thus the “skin“ and “muscle“ compartments in the Aladin® Air Z O2 show
variable half-time periods and saturation tolerances. Decompression information is calculated according
to the diver‘s individual workload and decrease in skin temperature. The decrease in skin temperature is
based upon the water temperature and the dive time. By considering these changes in saturation, the
time that must be spent at the surface prior to flying may be considerably lengthened, depending upon
the depth, time, and temperature of a dive, as well as the diver‘s workload during that dive.

As I said in my first post, I don't have any specific info about the heart rate monitoring computer, but it would seem to be a simple extension of the current model that adjusts for perceived workload as inferred from air consumption and/or breathing pattern.

That exercise affects blood circulation, which in turn affects N2 ongassing and offgassing isn't anything new. For example, Dr. Deco did extensive studies about the effect of exercise on stationary bicycles on astronauts that were prebreathing O2 to offgas N2 before going to the lower pressure of the space suits used for the space walks.

The ZHL8 ADT algorithm is just an attempt to quantify a bit the general practice of extending decompression if one exercises more vigorously at depth than during decompression. It is an issue of relative levels of exercise, so absolute info on VO2 max isn't needed.

 

[MookieMoose]

The new UWATEC Galileo ad says it features a "heart rate monitor for Precise decompression calculations."

I just have never seen anyone talk about this. Is it something new or a gimmick?

Thanks in advance for any insight.

This seems pretty silly to me. It implies a level of precision that the current level of scientific understanding doesn't really support.

Cam

 

[Geoff_H]

As I said in my first post, I don't have any specific info about the heart rate monitoring computer, but it would seem to be a simple extension of the current model that adjusts for perceived workload as inferred from air consumption and/or breathing pattern.

From the reviews I have read, this is my understanding too. Not sure how useful it is over and above the function that adjusts the theoretical ongassing rate based on how much gas you are consuming (from the air integration). I would think that increased heart rate and increased breathing rate would be well correlated, but this is only a non-scientific guess.

I know for me, if my heart rate goes up my air consumption will also.

 

[Dr Deco]

Hello Readers:

I was away for several days in Wales and am just returning to the Board.

The idea of heart rate is interesting, as is air consumption.

To my knowledge, however, there is no laboratory data to indicate how much – if any – adjustment should be made for nitrogen uptake and elimination in these situations. For depressurization to altitude, I did develop an off gassing algorithm at NASA starting with complete tissue saturation; this is the case for an astronaut.

Uptake and elimination is an entirely different matter. No doubt, the programmer simply entered some modifying factor into the algorithm and presents this as the gospel truth. This is nice for marketing but the modifications are guesswork, as far as I am aware.

Computer makers do not perform laboratory research for their devices. Many devices however do trace their pedigree to the PADI Recreational Dive Planner that I tested in 1986.

 

[bobhog]

The Galileo manual doesn’t give specifics on the science behind heart rate monitoring and their predictive algorithms but they point out that heart rate is used as a predictor of work load but that the Galileo computer can toggle between the highest of heart rate or respiration.

British Journal of Sports Medicine, Journal of Physiology Education, American Journal of Physiology, National Institutes of Health, and many others are very interested in how diving affects heart rate and how sympathetic/parasympathetic responses to diving affect blood flow and compartmental allocation. A significant amount of research has been dedicated to the lowering of heart rate during scuba diving (diving brachycardia) and how what effect this will have on the diver. Some studies also point to right ventricular increase in size (ventricular hypertrophy) and the implications therein.

I doubt UWATEC is doing much past work load considerations when factoring in heart rate because it seems prevailing science has little data on nitrogen loading or oxygen toxicity as a factor of heart rate (none I've found yet but would love if someone would be kind enough to post it). As a physiologist, I bought the Galileo in part because of heart rate tracking. There is certainly future knowledge worth gleaning from collecting randomized data from the diving community on heart rate, perceived exertion, and nitrogen loading/oxygen toxicity. I would like to know what research indicates to where blood is shunted during diving brachycardia (is this a typical parasympathetic response?).

I would also be interested in learning about nitrogen/oxygen on athletic divers vs. non-athletic divers. One could assume that those with higher VO2 would certainly have reduced nitrogen loading but is this more compartmental with athletes?