Exercise intensity is defined by a percentage of one-rep max for strength or a percentage of max heart rate or VO2 max for endurance, not perceived effort.

“The second one is the intensity. And that refers to in this context not perceived effort like wow that was a really intense workout. It is quite literally either a percentage of your one rep at max or a percentage of your maximum heart rate or V2 max. So for the strengthbased things you want to think about what's the percentage of the maximum weight I can lift one time. And that's that's what we're going to call one rep max or it's a percentage of my heart rate. Right? So if I tell you to get on a bike and I want you to do intervals and I want you at 75%. I'm typically referring to 75% of your max heart rate or V2 max or you know something like”