Taking regular breaks is crucial to studying.

It gives your mind a chance to digest and organize the information that you have absorbed. Even a 10 minute break every hour can be a huge help. Studying by cramming for long periods without taking breaks can lead to overload, and less recolition of what you have tried to absorb.

Spacing out your learning will actually decrease the total amount of study time that you need to learn a subject. Additionally, taking a break between studying two different subjects will help prevent confusion, especially if the two subjects are similar.

Take my word for it, I studied at the Open University for six years.