Should be at about a 50% pace – 50% of competitive rolling speed, 50% strength. If you want hard rolls, go to a competition class. This is about serotonin, not adrenalin. If the red mist descends, or even the yellow or orange mist, stop, breathe, and calm down.
There is no winning, no losing, just flowing. We are playing, not fighting.
Be like water, my friend. Try to flow around obstacles rather than crash through them. Yes, water crashes too, but not while you are flow rolling.
Try for continuous movement rather than dominance. Spend as much time escaping and playing and retaining guard as you do passing or getting and staying on top. Let yourself get swept a percentage of the time if your partner’s move is legit, that way you get to practice defence, escapes and guard retention.
Submissions should be catch and release. If you have to grind to get the pass or the sub, give it up, you are going too hard. Submissions should be fortuitous; they are not not really the aim of this type of training.
You should never be gasping for breath, and you should feel fresh enough after flow rolling for an hour today to easily be able to do it all again tomorrow.
You need some harder rounds if you are concerned about self defence or competition. You need to learn how to deal with pressure and aggression. But training this way all the time for multiple decades is unsustainable.
We seniors need to concentrate on having fun and rolling sustainably. I’m 67 now and want to be doing this into my eighties. I do an hour of flow rolling early on a Saturday morning, with partners from white belts to senior black belts, then go for a swim in the ocean with friends. Easily the most enjoyable training day of the week.
Firas Zahabi drops some logic bombs on the subject of training sustainably here.