Want to learn a new skill? Take some short breaks
I have been trying to remember 15 thousand words for the last 3 years during which I have similar experiences.Several times, I pushed myself hard to keep learning for hours, but ended up with efficiency decreasing as time went by. I may be unable to take in anything after two hours of intense learning. Then I try to rectify my own approach to find the most suitable method for myself. Following is my own experiences.
Whether the break is needed depends on my specific task. Whatever task I do, I try to keep doing it without any break for at least about 45 minutes.
If I’m coding, I need less intervals of break, and I can keep coding as if I enter a status called the mind flow. While if I’m reading and digesting a whole book, I need to stop sometimes to think. Well, if I’m remembering and digesting plenty of words and its usages, it’s better for me to take a break more frequently, maybe I will watch a short video about 20 minutes every 45 minutes, to clear my mind.IMO, it all about the ability to keep oneself concentrated. I’ve heard that some people can stay concentrated for a very long time, like several hours, and I’m not this type of person although I once experienced this state for two days and lost it forever.  And I get exhausted more quickly when I am less concentrated than I am.