@design_RG Maybe the way we sit can affect our thinking also and ability to delve deeper into a book. With our constant sitting (which is definitely a thing we have been doing enormously these last decades - maybe at the same time than computers came in our lives) we have changed the way we use our bodies and the way it gets nourished or not in some way.
There is a great woman called Katy Bowman (biomechanic) https://www.nutritiousmovement.com whose focus is on this problem of not moving. Also Movnat