Just a soft-question that has been bugging me for a long time:
How does one deal with mental fatigue when studying math?
I am interested in Mathematics, but when studying say Galois Theory and Analysis intensely after around one and a half hours, my brain starts to get foggy and my mental condition drops to suboptimal levels.
I would wish to continue studying, but these circumstances forces me to take a break. It is truly a case of "the spirit is willing but the brain is weak".
How do people maintain concentration over longer periods of time? Is this ability trainable or genetic? (Other than taking illegal drugs like Erdős.)
I know this is a really soft question, but I guess asking mathematicians is the best choice since the subject of Mathematics require the most mental concentration compared to other subjects.