Serious answer, own experience, is stamina. I suspect is when you're low stamina, you easily get tired and the body automatically will want to cum. When I low stamina can't last long, but once I train and good stamina, can last very long, longest I had was 1 hour+.

Try it, no need jog, if stay condo, just climb the condo stairs, try go 20 floors one shot. After 1 week you will get used to it, 2 weeks you will easily climb it while playing phone.

3 weeks confirm can piap 1 hour