The question is interesting. We could all make some evidential hypothesis, like extra oxigen compsumption by the an heavy mussle mass. To prove them though, we would need to be able to isolate the factors we want to measure, and there are so many factors for good static apnea that it would be hard to do. Searching for people that have anormal weigth could provide some evidence of causality. I think I'm one of those person, being 5'11" and weighing 100lbs. I'm new to the world of apnea, I'm not training much outside of my apnea courses, but this week I did a dry pb of 4min40 at my sister's house. I guess it's not that good since so many people here do over 5min, but I started at the same time as my brother and sister and they didn't go over 3min yet, which might means that my weight predisposes me for static apnea.
Benjamin Leclerc