A power nap is a short sleep that terminates before deep sleep. Power naps restore alertness, performance, and learning ability.
Just like power naps, short breaks too are extremely powerful and useful. Apart from breaking the monotonicity of doing something non-stop, they also serve to re-energize. That usually means more efficiency and effectiveness. When we get back to the task after a short break, we can do it with far lesser effort or accomplish more with a similar effort.
Breaks also help by allowing us to step back to see the bigger picture. When we are involved with something (like CAT Prep) day in and day out, we become so involved with the micro, that we could just end up missing the macro.
Finally, breaks allow us to see that there is much more to life, even as we strive for what we aspire for.
If you are feeling jaded, take a short break. Come back stronger!