Breathing rate, air integrated computers and DCI correlation

[beaverdivers]

Haldane noted that exercise at depth increases nitrogen uptake

Increased Workload increases on gassing of nitrogen!

It was noted that exercise during depress, exercise was harmful if vigorous.

Thus, DCS is a function of Workload.

 

[JohnN]

Increased Workload increases on gassing of nitrogen!Thus, DCS is a function of Workload.

Your grasp of the science of decompression is simply staggering.

 

[redacted]

Increased Workload increases on gassing of nitrogen!Thus, DCS is a function of Workload.

How does workload effect off-gassing when a compartment transitions from on-gassing to off-gassing? How is that handled by computers that monitor heart rate and/or gas consumption?

 

[tracydr]

:shocked2:

Hello Readers :

There appears to be also questions regarding exercise and DCS. Some believe that exercise and DCS is a new topic without much to back up the idea of harm. The following excerpts show this not to be the case. Here is an old study comparing bubble formation in exercising and resting legs [in rats, I believe] from E. N. Harvey.

Comparing these two groups [active and resting], it is clear that stimulation of the hind legs causes a very significant increases in the incidence of bubble production (under reduced pressure). If only one leg is stimulated it is found that bubbles come only from that leg.
- E. Newton Harvey
Decompression Sickness, 1951

J. S Haldane noted the relationship between activity and DCS; he suggested mild exercise during decompression to promote offgassing.

Exercise and DCS is a very old topic and backed by considerable work designing decompression schedules for humans. Not all is laboratory research of the type performed today; much of it is a century old. Haldane noted that exercise at depth increases nitrogen uptake and exercise [mild] should therefore be performed during depress.

…it seems desirable that where work has been done in compressed air, so that the muscles and associated tissues have become rapidly saturated with nitrogen, there should also be muscular exertion during decompression. The rate of desaturation will thus be increased so as to compensate for its increased rate of saturation.

- J. S. Haldane, “The prevention of compressed-air illness. “ J. Hygiene Camb. 1908 p.354

As an additional safeguard, the diver is directed to keep his arms and legs constantly moving during each stoppage, so as to increase the rate of circulation and guard against the chance of the rate of desaturation during his ascent being proportionally less than the rate of saturation during his stay on the bottom while he was doing work.

- J. S. Haldane, The prevention of compressed-
air illness. J. Hygiene Camb. 1908 p. 367


It was noted that exercise during depress, exercise was harmful if vigorous.

When it was proved that exercise definitely increased susceptibility to altitude bends and chokes, controlled experiments were carried out at the Experimental Diving Unit by Van Der Aue and his coworkers. The results of rapid decompression after prolonged exposure at a critical depth indicated that exercise following exposure increased susceptibility to bends.

- A. R. Behnke, Chapter III, Decompression Sickness, 1951


Below are some papers of mine from recent years. They were performed in altitude chamber studies related to NASA work in spacesuits.

Conkin J, MR Powell. Strict adynamia reduces the risk of hypobaric decompression sickness. Undersea Hyperbaric Med., 26 (Suppl) pp. 56. (1999).

Conkin J, Powell MR. Lower body adynamia as a factor to reduce the risk of hypobaric decompression sickness. Aviat. Space Environ. Med. 72, 202 – 214, (2001)

Dervay JP, Powell MR, Butler B, Fife CE. The effect of exercise and rest duration on the generation of venous gas bubbles at altitude. Aviat Space Environ Med. 2002;73(1):22-7.

Dr Deco :doctor:

Thanks very much Dr.Deco. I love your book.
Still trying to picture a little rat on scuba lifting weights with one leg.
How hard was it to ultrasound those little rats legs?

 

[CT Sean]

Increased Workload increases on gassing of nitrogen!Thus, DCS is a function of Workload.

Dr Deco's posts define workload as exercise. Breathing fast and and shallow is not exercise

 

[beaverdivers]

How does workload effect off-gassing when a compartment transitions from on-gassing to off-gassing? How is that handled by computers that monitor heart rate and/or gas consumption?

At the base of any decompression calculation there is the transport of nitrogen from the lungs to the blood and from there to the tissues during on gassing, and the same again in reverse during off gassing.

As such it is obvious that the single most important parameter in a decompression calculation is the rate at which blood travels through the body. During heavy exercise, the total blood flow from the heart can be up to 4 times higher than while at rest. This increase in blood flow is rather unevenly distributed, with some tissues such as the Central Nervous System and the brain being unaffected,while others like the muscles receiving up to ten times more blood than at rest.

UWATEC introduced workload-induced decompression algorithm compensation in1995 with the Aladin Air X dive computer.The workload estimation was based on changes in the breathing pattern as detected by the hoseless high pressure transmitter,and the decompression calculation in four of the 8 compartments in the ZH-L8 ADT model was changed accordingly.

 

[redacted]

At the base of any decompression calculation there is the transport of nitrogen from the lungs to the blood and from there to the tissues during on gassing, and the same again in reverse during off gassing.

As such it is obvious that the single most important parameter in a decompression calculation is the rate at which blood travels through the body. During heavy exercise, the total blood flow from the heart can be up to 4 times higher than while at rest. This increase in blood flow is rather unevenly distributed, with some tissues such as the Central Nervous System and the brain being unaffected,while others like the muscles receiving up to ten times more blood than at rest.

UWATEC introduced workload-induced decompression algorithm compensation in1995 with the Aladin Air X dive computer.The workload estimation was based on changes in the breathing pattern as detected by the hoseless high pressure transmitter,and the decompression calculation in four of the 8 compartments in the ZH-L8 ADT model was changed accordingly.

Nonsense. Don't you think you need to compare the effects of that parameter with other variables? Or is it your contention that a dive computer based solely on blood flow rate would be better than a dive computer based solely on depth (partial pressure) as most computers are today?

By the way, how can it be that there is no recognized safety difference in computers that operate only based on partial pressure as compared to those that treat partial pressure and heart rate in their algorithm? If heart rate were so important, why would a manufacturer provide a user capability to turn that feature off? Wouldn't that be like a car manufacturer providing the driver a capability to turn off the braking system?

Sometimes your hard sell techniques are just not credible.

 

[CT Sean]

At the base of any decompression calculation there is the transport of nitrogen from the lungs to the blood and from there to the tissues during on gassing, and the same again in reverse during off gassing.

As such it is obvious that the single most important parameter in a decompression calculation is the rate at which blood travels through the body. During heavy exercise, the total blood flow from the heart can be up to 4 times higher than while at rest. This increase in blood flow is rather unevenly distributed, with some tissues such as the Central Nervous System and the brain being unaffected,while others like the muscles receiving up to ten times more blood than at rest.

UWATEC introduced workload-induced decompression algorithm compensation in1995 with the Aladin Air X dive computer.The workload estimation was based on changes in the breathing pattern as detected by the hoseless high pressure transmitter,and the decompression calculation in four of the 8 compartments in the ZH-L8 ADT model was changed accordingly.

Even though I just posted it, I feel it bears repeating. Breathing fast and shallow does not equal exercising

 

[mathauck0814]

I just analyzed Saturday's dive. 165fsw for :31 minutes on Tx23/30, followed by decompression on 50% and 80%.

Oh crap, now you've done it ... here comes ten pages of why EAN80 is a bad gas for decompression...

 

[HIGHwing]

Oh crap, now you've done it ... here comes ten pages of why EAN80 is a bad gas for decompression...

Hey, I was out of scrubber! BUT, don't worry, I've restocked!!

(And for the record, I don't think 80% is a bad gas if you hold the 20ft stop instead of ascending to the 10ft stop. This strategy allows me to come on the highest mix early (at the 30ft stop) and they stay under 1.6PO2 for the 20ft stop. Considering the wave height/period if it's really sporty, the 10ft stop is far too fatiguing to hold for an hour or more, accordingly, I don't bother with it. In caves, I just get 100% from Cave Country or Amigos and I'm not too worried about waves and buoyancy fatigue in that environment.