This is the only hour in a day where students do something other than math or reading.

Do you consider mindfulness practice math or reading?

I suspect this will go like most of the educational suggestions:

The article isn't about a suggestion but a real world experiment.

Nice to know that if you compress all the remaining subjects into one hour daily, there is enough time left for composing blog posts.

There no suggestion that subjects get compressed into one hour daily. It a shedule of a single day without a suggestion that every day is the same.