When I’m rolling or sparring, what should I do when my cardio starts to go down?

I roll in BJJ gi and no gi. I also do kickboxing and spar.

These are both for fun for cardio, 0 intentions of competing currently.

In sparring, there’s the last 2 sets of about 3:00 minutes. And during that last minute, my cardio and breathing are starting to get heavy. But obviously my opponent isn’t stopping just because I get tired. I sit the next round out, but what do I during that time before the round ends?

Same with BJJ, I’m getting tired and my opponent isn’t going to stop, a lot of them do compete and are going hard.

That’s the point where my body starts to focus on breathing and I’m focusing very hard to keep form and not be sloppy. My brain is still fast enough and knows what to do. But my body can’t execute always be fast enough at that point.