Drowning

Characters in rough water must make a Strength test as a free action each round to avoid taking in water. If the test is failed, the character suffers Fatigue (which means heavy armor may cause more Shock!)

Swimming
If the Strength test to avoid drowning succeeds with a Good result, a character may also move half her Dexterity in meters. She may move her full Dexterity in meters with an Outstanding success. Characters can’t '''run''' while swimming without equipment or other adaptations.

Holding One’s Breath
In a completely airless environment, characters can generally hold their breath for a number of rounds equal to half their Strength, rounded up. After that, a character starts to suffocate. Suffocation causes 2 Shock per round until the character is KO’ed. She takes a Wound each round thereafter until she expires. Characters may not use the Recovery option while holding their breath.

Publication: Core Rules