have a break
Maybe there are living concentration wonders, but most people can only concentrate for a limited time. How long differs from person to person, but one five minute break for each hour will be too less for most people. Your mind has to relax too. And do not try to squeeze something important or urgent into your break. It is about relaxing, not switching
You shouldn't try to learn for more than six hours per day anyway, because at one point you will start to "overlearn", so that the first things you learned that day will be overwritten or forgotten.