There was a monk in tantric school who closed his door for three years in March, without eating or drinking. It's really amazing. How did he do it? Can many people do it?
I don't want to explain it to you from a Buddhist point of view. Can think scientifically. As far as the development level of human brain is concerned, even Einstein has only developed to 13%. If it reaches 20%, you can win ten Nobel Prizes! The human body is the same! Nowadays, people don't know 10% about their bodies, and many intractable diseases can't be cured! Where is the limit of the human body? We don't even know! What I hate most are those idiots who pretend Buddhism is superstition and don't know how to pretend to understand!