15 seconds without oxygen seems low

I reread Mothership’s Player Survival guide and it struck me as odd that it says that “in space you can last 15 seconds without oxygen before falling unconscious”.

And it seems very low. Maybe the key is that it’s only if you are in space? In the cold, vacuum space? Of course I couldn’t help myself and tried holding my breath for 30 seconds and it was very easy with an atmosphere. And I’m no astronaut, athlete, nor scuba diver.

I’m thinking about houseruling that if you’re able to at least take a deep breath few short breaths to oxygenate and then let go beforehand, you should add a number of seconds equal to your Body save. And any previous training would add an advantage.

Does that seem reasonable?