Yes, it can be! We often get exhausted and feel like we can't take any more information.
In my experience, taking breaks is the best solution for this. I read a research a while back (Don't remember where!) that your performance deteriorates after 45-60 mins of studying depending upon your capacity. If you take a 5-15 min break, however, you do much better.
You can exercise, eat, mediate, dance, listen to music or an inspirational tape if you want in this mini tape. Closing your eyes and lying doing for a while is very relaxing.
Do not use your phone. Your phone has text all over and reading does exhaust you.
I usually get really distracted if I take mini breaks after studying for an hour and don't return to books for another hour. If you have the same problem, you can study for 2-3 hours straight and then take a longer break like a shower, have a long lunch break or a walk around the park.