How did you feel after that Deco ?
- Thread starter Remy B.
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DevonDiver
N/A
Depending on what theories you identify with, there's a suggestion that post-dive fatigue (decompression stress / sub-clinical DCS) results from complement system (immune) activation to micro-emboli (micro-bubbles) perfusion in the body.
Medicine has proven that micro-emboli are indeed recognized as antigens and activate the complement system.
A number of aspects from immune response can cause fatigue or malaise.. such as the release of serotonin or increased hemoconcentration....and/or if an immune-response is limited to the brain/CNS compartment (believed to be separated from the rest of the body - see: Does the brain possess an independent immune compartment?).
I won't even mention issues of protein clotting and brain lesions..
(see my article Subclinical DCS, Decompression Stress and Post-Dive Fatigue for full details)
So, if we're to believe that micro-emboli are the cause of undeserved post-dive fatigue, then we have to look at all the aspects that promote micro-emboli creation and longevity.
GF settings play a role in managing the micro-bubble process:
- - - GF-Lo (is suggested to) control initial bubble formation and rapid resolution. Whereby:
Pamb + Bubble Surface Tension > Pinternal
causes bubbles to collapse.
--- GF-Hi (is suggested to) resolve remaining bubbles, especially if high differential is created across the bubble surface using richer O2 mixes, and is time dependant...as the process of bubble collapse is now diffusion based.
Ascent rates are also important. Creating a rapid increase in Pamb is hypothesised to resolve bubbles at an early stage. Inert gas tissue pressure elevates quicker than inert gas can diffuse into a bubble. This crushes the bubble.
Too slow ascents from bottom depth (to first stop) may exacerbate bubble longevity. A slower rise in Pamb could allow inert gas to dissolve into bubbles at a rate equal, or closer to, the elevation of inert gas tissue pressure. Thus, bubbles would collapse slower, or not at all.
Many novice technical divers do struggle to maintain precise 9-10m per minute ascents...
So... it's a case of 'prevention' or quick-resolution (deep factors) versus 'cure' or slow-resolution (shallow factors).
When it comes to the scale of complement (immune) system reaction, I'd suggest that the degree of response would be dictated by the number of bubbles PLUS the amount of time they persist in the body.
It could be that delaying the resolution of micro-emboli until the shallow deco phase is not timely enough to prevent complement system activation.
Once an inmuno-response is activated, and if allowed to become severe enough, the diver could still experience fatigue/malaise even after very effective shallow decompression.
If not resolved satisfactorily on the deepest stops, the time of micro-emboli persistence, and consequent severity of complement system activation, will be greatly influenced by the intermediate deco stop schedule.
Once reaching O2 deco (assuming O2 is utilised), we might assume that more effective micro-emboli resolution starts to occur due to the oxygen window effect.
However, by that time, the damage may already be done. You could potentially surface 'clean', but already be suffering blood-chemistry and/or CNS compartment effects from the intermediate-late stage processes of an immuno-reaction that was triggered in the ascent phase of the dive.
It should also be noted that there is a theory that frequent exposure to micro-emboli initiated complement system activation creates a desensitising effect.
It's possible that if someone dives very frequently then the immuno-reaction to micro-emboli becomes less severe, or even ceases altogether (see Diver0001's comment on pg1).
Resolving bubbles in the shallow deco phase may not be entirely successful in preventing complement system activation. Allowing micro-emboli to resolve naturally post-dive is, of course, even less successful.
VPM-B is a dual-phase model. It calculates deeper deco based specifically on mathematics that model predicted micro-emboli growth/shrinkage. Thus it gives deeper stops based on a 'sweet spot' where bubble surface tension causes shrinkage.
At the same time, VPM-B functions as a content model (dissolved gas) and accounts for slower tissue saturation - calculating subsequent deco stops accordingly.
Buhlmann ZH-L16 is a pure content model. However, the addition of GF allows us to replicate the deeper profiles (via GF-Lo) we'd recognise from VPM-B or other bubble models.
At the same time, we can dictate (via GF-Hi) the overall deco time - primarily allocated to shallower stops.
When it comes to GF selection, I think there is NO ideal or singular perfect universal setting.
For a start, it is dependent on the dive depth. A perceived beneficial GF-Lo in the 40-60m range is unlikely to have the same benefits in the 60-90m range etc etc.
We also have to consider GF-Lo in relation to breathing gas at first stop depth. This accounts for the potential to create a better diffusion gradient through has switches.
Of course, there also has to be some consideration for the need to prevent excessive overall deco by removing helium and/or nitrogen as early as possible. Bottom gas deco stops are inherently inefficient.
We have a situation where GF optimisation (determined by post-dive observation of vitality/fatigue) can/should vary on each dive, according to the dive parameters, for each diver... and can vary even for the same diver dependant on their recent diving habits.
The only real solution, as I see it, is for a slower process of trial and error experimentation; monitoring post-dive fatigue/vitality in relation to a myriad of possible influencing factors.
Sometimes, there's just no substitute for experience
Medicine has proven that micro-emboli are indeed recognized as antigens and activate the complement system.
A number of aspects from immune response can cause fatigue or malaise.. such as the release of serotonin or increased hemoconcentration....and/or if an immune-response is limited to the brain/CNS compartment (believed to be separated from the rest of the body - see: Does the brain possess an independent immune compartment?).
I won't even mention issues of protein clotting and brain lesions..
(see my article Subclinical DCS, Decompression Stress and Post-Dive Fatigue for full details)
So, if we're to believe that micro-emboli are the cause of undeserved post-dive fatigue, then we have to look at all the aspects that promote micro-emboli creation and longevity.
GF settings play a role in managing the micro-bubble process:
- - - GF-Lo (is suggested to) control initial bubble formation and rapid resolution. Whereby:
Pamb + Bubble Surface Tension > Pinternal
causes bubbles to collapse.
--- GF-Hi (is suggested to) resolve remaining bubbles, especially if high differential is created across the bubble surface using richer O2 mixes, and is time dependant...as the process of bubble collapse is now diffusion based.
Ascent rates are also important. Creating a rapid increase in Pamb is hypothesised to resolve bubbles at an early stage. Inert gas tissue pressure elevates quicker than inert gas can diffuse into a bubble. This crushes the bubble.
Too slow ascents from bottom depth (to first stop) may exacerbate bubble longevity. A slower rise in Pamb could allow inert gas to dissolve into bubbles at a rate equal, or closer to, the elevation of inert gas tissue pressure. Thus, bubbles would collapse slower, or not at all.
Many novice technical divers do struggle to maintain precise 9-10m per minute ascents...
So... it's a case of 'prevention' or quick-resolution (deep factors) versus 'cure' or slow-resolution (shallow factors).
When it comes to the scale of complement (immune) system reaction, I'd suggest that the degree of response would be dictated by the number of bubbles PLUS the amount of time they persist in the body.
It could be that delaying the resolution of micro-emboli until the shallow deco phase is not timely enough to prevent complement system activation.
Once an inmuno-response is activated, and if allowed to become severe enough, the diver could still experience fatigue/malaise even after very effective shallow decompression.
If not resolved satisfactorily on the deepest stops, the time of micro-emboli persistence, and consequent severity of complement system activation, will be greatly influenced by the intermediate deco stop schedule.
Once reaching O2 deco (assuming O2 is utilised), we might assume that more effective micro-emboli resolution starts to occur due to the oxygen window effect.
However, by that time, the damage may already be done. You could potentially surface 'clean', but already be suffering blood-chemistry and/or CNS compartment effects from the intermediate-late stage processes of an immuno-reaction that was triggered in the ascent phase of the dive.
It should also be noted that there is a theory that frequent exposure to micro-emboli initiated complement system activation creates a desensitising effect.
It's possible that if someone dives very frequently then the immuno-reaction to micro-emboli becomes less severe, or even ceases altogether (see Diver0001's comment on pg1).
Resolving bubbles in the shallow deco phase may not be entirely successful in preventing complement system activation. Allowing micro-emboli to resolve naturally post-dive is, of course, even less successful.
VPM-B is a dual-phase model. It calculates deeper deco based specifically on mathematics that model predicted micro-emboli growth/shrinkage. Thus it gives deeper stops based on a 'sweet spot' where bubble surface tension causes shrinkage.
At the same time, VPM-B functions as a content model (dissolved gas) and accounts for slower tissue saturation - calculating subsequent deco stops accordingly.
Buhlmann ZH-L16 is a pure content model. However, the addition of GF allows us to replicate the deeper profiles (via GF-Lo) we'd recognise from VPM-B or other bubble models.
At the same time, we can dictate (via GF-Hi) the overall deco time - primarily allocated to shallower stops.
When it comes to GF selection, I think there is NO ideal or singular perfect universal setting.
For a start, it is dependent on the dive depth. A perceived beneficial GF-Lo in the 40-60m range is unlikely to have the same benefits in the 60-90m range etc etc.
We also have to consider GF-Lo in relation to breathing gas at first stop depth. This accounts for the potential to create a better diffusion gradient through has switches.
Of course, there also has to be some consideration for the need to prevent excessive overall deco by removing helium and/or nitrogen as early as possible. Bottom gas deco stops are inherently inefficient.
We have a situation where GF optimisation (determined by post-dive observation of vitality/fatigue) can/should vary on each dive, according to the dive parameters, for each diver... and can vary even for the same diver dependant on their recent diving habits.
The only real solution, as I see it, is for a slower process of trial and error experimentation; monitoring post-dive fatigue/vitality in relation to a myriad of possible influencing factors.
Sometimes, there's just no substitute for experience
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Jack Hammer
Contributor
I'm usually diving 30/85. on the rare occasion I don't "feel" clear when my deco schedule is done I will stay an extra 5 or so mins on O2 at 20'. that has seemed to be enough. I typically finish deco that with a slow ascent of 3-5mins to the surface depending on my dive profile and mood.
Great post Andy, thanks.
I can relate to this, when I started to dive, I was tired after the dives, as I was as well not in control on my ascents, always in my NDL.
As I learned to control more my ascent rates, this sensation of being a little tired started to disappear.
I can relate to this, when I started to dive, I was tired after the dives, as I was as well not in control on my ascents, always in my NDL.
As I learned to control more my ascent rates, this sensation of being a little tired started to disappear.
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There is so much beyond exposure (depth/time) that can be at play.
Pre-dive hydration. Rest the night before. Recent diving experience (several people believe that your body can become more efficient at decompression by doing frequent and recent diving). Thermal stress. Pre-dive workload. Post-dive workload. Physical and mental fatigue. The list goes on and on.
Remy, it appears that you're looking for a magic bullet, but there isn't one.
However, I would say if you're constantly fatigued after every dive then you may have something physiological going on.
Pre-dive hydration. Rest the night before. Recent diving experience (several people believe that your body can become more efficient at decompression by doing frequent and recent diving). Thermal stress. Pre-dive workload. Post-dive workload. Physical and mental fatigue. The list goes on and on.
Remy, it appears that you're looking for a magic bullet, but there isn't one.
However, I would say if you're constantly fatigued after every dive then you may have something physiological going on.
No I'm not Looking for a magic bullet, it is a general question, I see frequently that they write feeling like shaiit, with that and this profile and they changed this and added that, but no really a list, everybody is different but at the same time we are the same humanly body that walks around the globe, so there are similarities.
I'm just curios if I can see a trend of from what I have to stay away from, and what conservatism is more the common choice.
Fatigue have a wide band it was not like I could do nothing, I kept my same routine, go to bed at the same time, but like I mention I noticed that this is not the case anymore, probably because i have better control on my ascents.
I'm just curios if I can see a trend of from what I have to stay away from, and what conservatism is more the common choice.
Fatigue have a wide band it was not like I could do nothing, I kept my same routine, go to bed at the same time, but like I mention I noticed that this is not the case anymore, probably because i have better control on my ascents.
I generally feel fine after diving deep.
The day before I do not drink alcohol, and restrict my coffee intake to two cups of espresso only. I probably over consume water to keep hydrated generally around 250ml per hour from when I awake at 0700 until I go to bed at 2200, and yes before anyone asks I am up during the night for pee too.
My dive day starts at 0530 and involves a two hour drive first during which I am intaking additional fluids including isotonic drinks such as Pocari Sweat and Sports Water.
The standard dive is to 70m / 72m, depending on the tide, using a GF of 15/75 and breathing an 18/40 mix with a normal run time of around 80-90 mins and switching gases at 21m (50%) and 6m (100%).
The only tiring part is climbing back onto the boat with twin steels on my back, but after that I am generally fine.
The day before I do not drink alcohol, and restrict my coffee intake to two cups of espresso only. I probably over consume water to keep hydrated generally around 250ml per hour from when I awake at 0700 until I go to bed at 2200, and yes before anyone asks I am up during the night for pee too.
My dive day starts at 0530 and involves a two hour drive first during which I am intaking additional fluids including isotonic drinks such as Pocari Sweat and Sports Water.
The standard dive is to 70m / 72m, depending on the tide, using a GF of 15/75 and breathing an 18/40 mix with a normal run time of around 80-90 mins and switching gases at 21m (50%) and 6m (100%).
The only tiring part is climbing back onto the boat with twin steels on my back, but after that I am generally fine.
I don't understand this. You start off talking about ascent rates so it seems to be about reducing ambient pressure but then talk about a rapid increase in ambient (Pamb being ambient pressure I assume) crushing bubbles. Can you explain?
I usually do deco dives on boats with lifts.
Lucky you
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