Fast tissues? Long tissues? What is this?

[Zef]

Here is some basic info from a Google AI overview...it doesn't mention muscle tissue but one should note that muscle tissue is considered an intermediate or slow-to-intermediate type of tissue (faster than fat and bone, but slower than what is listed as "fast" type tissues:

In scuba diving, fast tissues have good blood supply and low capacity for absorbed gases, allowing them to absorb and release inert gases (like nitrogen) quickly, while slow tissues have poor blood flow and/or high lipid content, leading to slow gas uptake and release. Fast tissues include the blood, major organs, and central nervous system, while slow tissues include fat, bone, ligaments, and cartilage.

Fast Tissues

• Characteristics: High perfusion (blood flow) and relatively low gas-holding capacity.
  
  
• Examples: Blood, lungs, major organs, and the central nervous system.
  
  
• Behavior: They reach equilibrium with the surrounding pressure very quickly, meaning they absorb and release nitrogen at a much faster rate than slow tissues.

Slow Tissues

• Characteristics: Low perfusion and/or a high capacity for storing gases (especially lipid-rich tissues like fat).
  
  
• Examples: Fat, bone, ligaments, tendons, and cartilage.
  
  
• Behavior: They build up a gas load more slowly and release it more slowly as well. They can remain saturated for a longer period, which is a critical factor in managing decompression.

Why it Matters

• Decompression theory:
  The rate at which a tissue absorbs and releases gas is described by its "half-time". Fast tissues have short half-times (e.g., 5 minutes), while slow tissues have long half-times (e.g., 240 minutes).
  
  
• Decompression sickness (DCS):
  When a diver ascends, the decrease in pressure can cause dissolved nitrogen to form bubbles in the body. Fast tissues release their nitrogen quickly during ascent, but slow tissues, which retain nitrogen for longer, can become supersaturated and contribute to DCS.
  
  
• Dive computers and tables:
  Dive computers and decompression schedules are designed to account for these different tissue types, modeling their on-gassing and off-gassing to ensure safe ascent profiles and prevent bubble formation.
  
  

 

[NAUI Wowie]

Your thinking is sound, but the researchers and developers of the decompression algorithms your computer runs on caution us there is no direct correspondence known between specific tissues and the so-called compartments that the algorithm divides decompression into. So, we know that various tissues behave in a range from fast to slow, but exactly which tissues fall where isn't well understood.

Thats kind of wild! So its like quantum physics lol. I have read a book on quantum theory broken down for us peasant folk and found it fascinating. But id think they would have researched that extensively? hmm

 

[Lorenzoid]

Ah ok. Yes on diversalertnetwork they said long. I of course understand the basics of decompression also just was curious if there are actually different organs that absorb nitrogen differently. If it is actually just discussing long term nitrogen loading over a period of multi dive days then im good with that. If 24 hours isnt enough time to offload 100% is what im guessing. I figured now that its on instagram if I dont know then a LOT of casual divers will be thinking like me.

Yes, different tissues "absorb" gas at different rates when you descend, and conversely those tissues release gas at different rates when you ascend.

The great thing about diving is that the casual diver is free to learn about this or be ignorant about it to whatever extent they wish, and they can still dive safely. But knowledge is good.

 

[NAUI Wowie]

Here is some basic info from a Google AI overview...it doesn't mention muscle tissue but one should note that muscle tissue is considered an intermediate or slow-to-intermediate type of tissue (faster than fat and bone, but slower than what is listed as "fast" type tissues:

In scuba diving, fast tissues have good blood supply and low capacity for absorbed gases, allowing them to absorb and release inert gases (like nitrogen) quickly, while slow tissues have poor blood flow and/or high lipid content, leading to slow gas uptake and release. Fast tissues include the blood, major organs, and central nervous system, while slow tissues include fat, bone, ligaments, and cartilage.

Fast Tissues

• Characteristics: High perfusion (blood flow) and relatively low gas-holding capacity.
  
  
• Examples: Blood, lungs, major organs, and the central nervous system.
  
  
• Behavior: They reach equilibrium with the surrounding pressure very quickly, meaning they absorb and release nitrogen at a much faster rate than slow tissues.

Slow Tissues

• Characteristics: Low perfusion and/or a high capacity for storing gases (especially lipid-rich tissues like fat).
  
  
• Examples: Fat, bone, ligaments, tendons, and cartilage.
  
  
• Behavior: They build up a gas load more slowly and release it more slowly as well. They can remain saturated for a longer period, which is a critical factor in managing decompression.

Why it Matters

• Decompression theory:
  The rate at which a tissue absorbs and releases gas is described by its "half-time". Fast tissues have short half-times (e.g., 5 minutes), while slow tissues have long half-times (e.g., 240 minutes).
  
  
• Decompression sickness (DCS):
  When a diver ascends, the decrease in pressure can cause dissolved nitrogen to form bubbles in the body. Fast tissues release their nitrogen quickly during ascent, but slow tissues, which retain nitrogen for longer, can become supersaturated and contribute to DCS.
  
  
• Dive computers and tables:
  Dive computers and decompression schedules are designed to account for these different tissue types, modeling their on-gassing and off-gassing to ensure safe ascent profiles and prevent bubble formation.
  

I had NO idea that tissues such as cartilege and bone were involved in absorbing nitrogen. Of course, it makes sense now as blood gets there somehow. Im feeling flashbacks of college anatomy having to dissect human cadavers.

 

[TrimixToo]

I disagree. I am not looking to discuss decompression. Ive got my two dive computers for that. Im wondering what fast tissues are? and what long tissues are? Are long tissues like kidneys liver etc?

are fast tissues your bloodstream?

I can give a rats backside about algorithyms

Nick pointed you in the right direction for getting the answers to your questions. If you don't care about how your dive computer works, that's fine. A lot of people don't. But note that decompression *theory* matters to the people who make those computers even when they are used by people who never intend to do decompression *diving*.

 

[rjack321]

Your thinking is sound, but the researchers and developers of the decompression algorithms your computer runs on caution us there is no direct correspondence known between specific tissues and the so-called compartments that the algorithm divides decompression into. So, we know that various tissues behave in a range from fast to slow, but exactly which tissues fall where isn't well understood.

Also there can be fast tissues and slow tissues within the same organ. Parts of the kidney, brain, liver, speen etc may on or off gas faster or slower than other parts. "Slow" is an abstract category not a biological unit

 

[MB NZ]

I have a basic understanding of decompression theory, but will admit that I never understood the practical application of compartment models for the diver. We come as an integrated unit, not a collection of theoretical compartments. Of course, the thinking diver may consider tissue compartments in choosing a gradient factor, but in practice, we make a choice based on historical safety and conservatism (real or perceived) and personal preference.

 

[J-Vo]

 

[NAUI Wowie]

Nick pointed you in the right direction for getting the answers to your questions. If you don't care about how your dive computer works, that's fine. A lot of people don't. But note that decompression *theory* matters to the people who make those computers even when they are used by people who never intend to do decompression *diving*.

Not wanting to be argumentative I will still say you are wrong. I wasnt asking about decompression at all. It was simple. Which tissues are fast and which are long? dont give a d... about decompression. I follow my perdix and teric. Im fine. I understand all the basics. What were those two tissues? thats it thats all. you are wrong bro. have a great day though . dont take it the wrong way but there aint NO newer or less experienced divers EVER going to check the decompression forum bro. literally ive never checked it and didnt want it moved there because us rec divers do not have an interest in that forum. Do you understand now??? Its the wrong forum for what i asked and wanted answers to.

everyones so worried about the right forum , for this the right forum is one that gets more views i wanted opinions from divers that dont know the term if they knew about it and those people wont BE in this forum

 

[rongoodman]

The theory is that blood and nerve tissue, for example, absorb and release inert gas very quickly, while fat, tendons and ligaments are much slower. Similar to the way radioactive decay is discussed, the models speak in terms of half times, IOW, how long for a specific compartment to load or unload half of gas it's capable of holding. After six half times, the compartment is considered to be fully saturated or cleared. In the Buhlmann 16 model, half times vary from 4 to 635 minutes, which means the time to fully load/unload a compartment can vary from 24 minutes to 63.5 hours. The tissue loading graphs on the Shearwaters are interesting to watch over a week of liveaboard diving with multiple dives daily. You typically see the fastest compartments clear during the surface intervals while the slowest ones barely move during the week. The intermediate ones are the ones controlling the NDLs.