Originally posted by Cap'n Bells:

I think it should be a skill that increases with swimming, ie irl treading water, so instead of drowning we can"rest" and swim a bit further.(rinse and repeat!) i dont think it should be a food based thing as this is the obverse of irl... imho :-)

https://valheim.fandom.com/wiki/Swim_(Skill)

Swim is a Skill in Valheim.

Leveling Up
It that can be raised through swimming in any body of water.

Experience is gained even if you are out of stamina & drowning. Wading and treading water do not grant xp.
Skill Benefits

Raising the Swim skill decreases the amount of stamina that is used and subsequently allows the player to swim farther before running out of stamina and taking damage.