Breath-Holding

[AlexanderHowl]

The record for holding breathe is 8:40 on normal air and 22:00 on pure oxygen (Stig Severinsen). In GURPS, that is not even possible for a HT 20 person who hyperventilated before doing nothing, and Stig did that while swimming slowly under the water. If we wanted to reflect his capabilities, we would need to give him Breath Holding 1.5 plus Breath Holding 1 (Only after hyperventilating on pure oxygen, -50%), which would allow us to reduce his HT to 16, which is more plausible. This is combined with the Breath Control skill.

[Gollum]

The world record for breath holding is 11:35 without oxygen inhalation (Stéphane Mifsud) and 24:03 with oxygen inhalation (Aleix Segura Vendrell).

Also note that, in GURPS terms, a record means a lucky dice roll : people don't succeed their record every day and rarely do it on the first try.

They also generally use what GURPS names extra effort wherever it is possible. Beating a world record is not something cool.

[Gollum]

Originally Posted by Alonsua

Maximum normal skill level is 20 [...]

Where did you find that rule? If it does exist, I totally skipped it. I was thinking that skills could go over 20, especially for world champions.

[AlexanderHowl]

You cannot use Extra-Effort for holding your breath, as it specifically forbids it by RAW (Campaigns, p. 357). Breath Control only increases time by 50% by RAW, no more and no less, as it does not give more time for margin of success. When you look at Stig's record, it is exceptional by GURPS standards because he was active, not sitting still.

[Gollum]

Originally Posted by AlexanderHowl

You cannot use Extra-Effort for holding your breath, as it specifically forbids it by RAW (Campaigns, p. 357).

Yes. I was speaking generally, which is why I wrote "wherever it is possible" (I was actually thinking about lifting records which appeared in another thread).

[Alonsua]

Breath Control at +10% per point over 10 and half a level of Breath-Holding allows to break world records at 20, so until we all come to an agreement I will stick to it.

[Gollum]

And there is no problem with that. The GM is free to put all caps he wants in order to maintain his own version of realism in his games: attribute cap of 20, 16 or even 14; skill cap of 35, 25 or even 20...

GURPS authors never answered to those questions (what is the realistic maximum for real humans?). Neither in the rules, nore in the forum. They don't want to impose their own vision of what is realistic or not, because, actually, nobody can really know.

Just note that such caps are not the rule. They are just your personnal choice, as GM. To avoid disappointment, clearly tell it to your players.

[Gollum]

Now that I have books at hand, and time to do it, I made a little research …

The rules for holding your breath (Basic Set, Campaigns, pages 351-352) say that without exertion, you can do it for HT x 10 seconds. So, someone with HT 15 (that is, someone outstandingly healthy) can do it for 150 seconds (2:30).

If he hyperventilated first, the time is multiplied by 1.5. Then, he can hold his breath for 225 seconds (3:45).
With a successful Breath Control roll, he can add 50% to that, at maximum (see Basic Set, Characters, page 182). Then, he can hold his breath for 337,5 seconds (5:37).

We are far from Stéphane Mifsud’s record. Even with HT 20, it would only give 450 seconds (7:30).

That is why, personally I would allow one level of Breath-holding for ordinary realistic humans. Surely with a required Unusual Background (very well trained free diver).

[Alonsua]

Originally Posted by Gollum

Now that I have books at hand, and time to do it, I made a little research …

The rules for holding your breath (Basic Set, Campaigns, pages 351-352) say that without exertion, you can do it for HT x 10 seconds. So, someone with HT 15 (that is, someone outstandingly healthy) can do it for 150 seconds (2:30).

If he hyperventilated first, the time is multiplied by 1.5. Then, he can hold his breath for 225 seconds (3:45).
With a successful Breath Control roll, he can add 50% to that, at maximum (see Basic Set, Characters, page 182). Then, he can hold his breath for 337,5 seconds (5:37).

We are far from Stéphane Mifsud’s record. Even with HT 20, it would only give 450 seconds (7:30).

That is why, personally I would allow one level of Breath-holding for ordinary realistic humans. Surely with a required Unusual Background (very well trained free diver).

Go ahead and make the calculations with my system:

HT-18* + Perk (Apnea training/Increase HT by 2; only when calculating Holding your Breath times using Breath Control).
Breath Control-20 (Instead of adding 50%, Breath Control adds some extra 10% per every level over 15, so at 20 it would add 100%).
Hyperventilate with pure oxygen (x2.5).
Breath-Holding 1/2 (x1.5).

Time = 20x10x2.5x2x1.5 = 1500 seconds, or 25 minutes.

*In my setting HT-18 can be achieved by an appropriate Resistant (Drowning) advantage costing 5 CP.

[whswhs]

I'm going to say that how long people can hold their breaths with pure oxygen is irrelevant. The RAW don't even mention breathing pure oxygen; they're for breathing air or other gaseous mixtures with a comparable partial pressure of oxygen. And the cited real world breath holding times indicate that breathing pure oxygen can approximately double or even triple the time achieved.