After only 15 to 20 minutes... take only a 5 minute break... 10 minutes is a waste of time.
During that time get up, pat the dog, empty the dishwasher, wash the dishes in the sink, pick your clothes up off the floor and put them away. Notice the task? The ones you hate to do, you only want to spend 5 minutes at them, so that you prefer to get back to work. If you want to relax further, take ten deep breaths and exhale them slowly before the start of your next study session.
By taking breaks equal in lenght to your study sessions you're throwing your out of study mode. We want a break only so that the mind can pause for a moment not to change pace.
Your technique is a bit like getting into a car driving it to the next town finding parking place walk around the block get into the car to start driving again.
Instead it would be better if you get started studying (get in the car), take a break (would be equal to pulling over into a gas station to check the map, to see if you are heading the right direction (are you learning what you need to be learning?), refuel (snack) and rehydrate (water) and then get going again.
Alex
[This message has been edited by AlexK (edited January 26, 2004).]