Reading and resulting thought are exercise for the brain. Some days you do a triathlon. Some just a stroll around the block. But both are better than mindlessly sitting on the sofa watching TV. Most TV is not exercise.

With that said, the mind is like other muscles. It has a limited capacity. That is, it also needs recovery. Reading "Your Brain at Work" was a seminal moment for me.

Finally, reading, observing (as mentioned above) and watching (i.e., TV or mobile device) seem to be three different things. They each engage the mind (and thought process differently). Based on my experience, there is a difference in people who read the news, and those who watch it. Reading, to me, is active. Watching is passive. How you think (about the news, for example) effects what you think. Or so it seems.