Apple Health Resting calories higher than BMR?

Resting calories are a generality in apps. Resting calories vary with composition. Fat burns less calories than lean tissue, lean tissue burns more than fat tissue.

Resting calories of people with identical weight would be higher for the person with less body fat.

Apple’s concept of “resting energy” does not correspond strictly to standard BMR the “resting energy” calories isn’t meant to be BMR but is based on the “non-workout” activity we do on a given day

Based on apples description of what resting energy is in the health app, it sounds like it is not traditional BMR, it sounds like they are just estimating non high activity calories burned based on heart rate. So this would be any activity not strenuous enough for Apple Watch to classify it as active heart rate. So I believe it varies if you are standing vs sitting. But again, just a guess based on the way the health app describes resting energy.