hmm, I seam to recall something like this being covered in another thread, or maybe it was another site where I discussed Hypoxia.
[myphilosophy]
First, I don't think I'd implement additional rules and rolls when the majority of the time the result will be the same as the books rules. See Note 2
[rant]
As I always say, simulating real life is pretty much impossible to do in a few die rolls and there has to be a compromise between complex game mechanics and playability.
Did the character know they were going into the water and take a big gulp of air so that they could hold their breath longer? Were they unconscious (not damaged, just drugged) and sucking in water as soon as they were put under? Perhaps, it's best for the GM to make some decisions instead of having detailed rules. The more detail and complexity you add, the more the rules will break in certain circumstances instead of bend.
[/rant]
Of course, it is also up to each group to decide for them self where that line is when the rules stop becoming an aid and start impeding game play.
[/myphilosophy]
[myanalysis]
With 1d6 damage, an average character would take at least a few rounds to become unconscious and worst case rolling all 6's still requires 4 rolls = 24 seconds for an average character to die. With an average of 3.5 pts of damage per roll, I believe it is 6 rounds = 36 seconds. On the other extreme, a low roller who rolls all 1's would last 21 rounds = over two minutes.
Perhaps 24 seconds is too low, but is > 2 min too much?
[some questions for us to ponder]
How long is realistic between no longer being able to hold your breath and unconsciousness? Between unconsciousness and death? How damaged is a person who goes without air and goes unconscious, how about going without air and 'dying' ie reaching the point that their heart stops, but then is pulled out of the water and revived?
[/some questions for us to ponder]
[/myanalysis]
[possibilities]
HOLDING BREATH
No endurance roll: A person can hold their breath for [Endurance x 6 sec] + 1min. This results in a range of 1min 6 sec on the extreme low end and 2min 30 sec for someone with a whopping 15 for dex. An average character would be holding their breath for 1min 42 sec.
For those that just have to roll dice: A person can hold their breath for [Endurance roll x 6 sec] + 1min.
Perhaps even [Whatever value your gaming group decides (for this example 1min 45 sec)] + [Endurance roll effect (positive for successful rolls, negative for unsuccessful ones) x 6 sec]
These can also have GM DMs for special cases such as the difference between someone knowing they are going underwater taking a larger gulp of air and someone that doesn't expect it, a person exerting them self (possibly to get out of the water) and using up oxygen faster or someone staying calm.
[Fact or fiction?]
When holding your breath ends does unconsciousness begin? Not necessarily. The longer you hold your breath, the closer you get to the breath-hold breakpoint where you can no longer resist the bodies breathing reflex and you start to breath in water while conscious. Or, you may go unconscious and the bodies breathing reflex will take over.
How do you determine which occurred? Did the person hold their breath to the point of passing out (game terms = 2 stats reduced to 0?) or is the person still conscious and just can't resist breathing? (game = no damage?) In either case they are sucking water into the lungs right? So it shouldn't matter?
Whether unconscious or conscious, the body knows not to let the water into the lungs so it will do it's best to send that refreshing gulp of water into the stomach and not the lungs. At some point after unconsciousness the laryngospasm relaxes. But how long after? And wait, when did that person that was able to hold there breath until they reached the breath-hold breakpoint and then started experiencing laryngospasm fall unconscious?
At some point, either while holding your breath or after, the brain will say it's time to take a vacation because their just isn't enough oxygen. This is when unconsciousness occurs.
From one medical web site
Cells of the brain will start to die within a few minutes if they are deprived of oxygen.
Another
The brain will die after approximately six minutes without oxygen.
[/Fact or fiction?]
[/possibilities]
[Conclusion]
Sorry, it is way too much detail for me to delve into any further at the moment but maybe some of you can use the information in some way.
The game mechanics may not be different if you are drowning or suffocating.
See http://www.caregiver.org/caregiver/jsp/content_node.jsp?nodeid=575 for information on possible cognitive and physical symptoms even after a person has recovered consciousness.
[/Conclusion]
[Notes]
Note 1: An average character has no positive or negative DM's and has 7's for all characteristics.
Note 2: I believe an endurance roll of 8 with no DM's is done a little under 50% of the time for an average character so the majority will fail on the first attempt. These endurance rolls are only gaining the character a few seconds before they would start taking damage.
[/Notes]
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