It is amusingly frustrating to finally learn this. Trying to convince my kids of it, and they don't believe me. At all.

Spouse is also dubious. Remarks that spending 20 minutes on a treadmill or out walking is actually somewhat hard to do. Not wrong, but it only gets easier if you do it. And then it starts to get a lot easier.

Try convincing them with incline walking - feels less daunting than running and has helped me get going! And now as it's gotten easier I'm starting to feel a natural running bug to up my intensity.