The Proposal

Whenever a character moves or takes an action to do anything strenuous (including dash), the amount of time that can continue to hold their breath is reduced by 1 more round. This is in addition to the normal loss of breath from passage of time.

Optionally, if a character takes damage, they must make a Constitution save equal to 10 plus the damage taken or lose another round of breath. If they fail the save by 5 or more, they lose two rounds instead.

The Reasoning

According to the rules as written in the Player’s Handbook, a character can hold their breath for a number of minutes equal to 1 plus their Constitution modifier (minimum 30 seconds), after which they are out of breath and can survive for a number of rounds equal to their Constitution modifier (minimum 1 round) before they lose consciousness and start dying.

My first problem is that there’s no distinction or mention of the difference between holding your breath (for minutes) and being out of breath but still conscious (a handful more rounds). Why the extra rounds at the end?

Secondarily, the rules make no mention about activity taken during this time. I have no problem believing that the average human (with 10 Constitution) can hold their breath for a minute, and that a more athletic person can hold it for upwards of three minutes—if they aren’t doing anything.

It seems nit-picky, perhaps, but consider how far your average PC can now swim underwater.

The Illustrative Example

Let’s say your character has 12 Constitution—slightly better than your average human—and a speed of 30 feet. This means that your character can stay underwater for 2 minutes plus 1 round (21 rounds total), and that their swim speed is effectively 15 feet, according again to the rules in the Player’s Handbook. Putting this together with the dash action, your character can swim 630 feet.

That’s a pretty fast time to start with. It’s nearly unthinkable though that anyone could do it without breathing the whole time. For some kind of baseline, when I swam competitively in high school, we would sometimes see how far we could swim underwater. My memory is a little foggy, but I think 50 yards was about my maximum, and the maximum for most of my peers on the team. That’s less than a quarter of the distance that the Player’s Handbook tells me I should be able to achieve. Even if my high school Constitution was average (a +0 modifier), that’s still less than half the distance.

Under my proposal, the hypothetical character’s underwater distance drops from 630 feet to 230 feet. That’s still quite a bit farther than I’ve ever managed to swim underwater as a trained competitive swimmer, but it’s much better than the current rules.

The Epilogue

Also my wife is very pretty. That’s not related to anything in this post, except that she’s sitting next to me patiently waiting for me to finish up and get to sleep.