Ask HN: how you increase cognitive load of an activity

A bunch of pop psychology articles led me to a strange solution to an issue.

I was listening to an audiobook while relaxing in my bedroom, but my mind kept wandering.

I don't have this problem during summer because I'm usually hiking outdoors while listening to audiobooks. But it's too cold to hike now.

The solution was to increase my cognitive load. I started tossing and catching a ball, alternating hands. My focus instantly improved. It was easier to listen to the audiobook.

In case anyone else on here has experienced this "Lifehack", please share simple ways you've discovered to increase cognitive load to improve your control over your attention.

* for those who are interested, the pop psychology articles referenced earlier had to do with the "increase challenge" part of Mihaly's "Flow".