Earlier quoted context omitted.
"The 3pm crash" is well documented and extremely common. Personally, I set up my schedule so I am not trying to do intellectual work between 3 and 4. Eat a snack, walk to the Starbucks down the street, go to the gym, take a boring meeting - anything, and then resume programming when my body is ready (usually around 4/4:30). The Spanish have siestas. There is nothing wrong with you - this is human nature. It's in the…
The Chinese also practice the afternoon nap. Lunch break at work in China is two hours: one for eating, one for sleeping. White-collar workers all get this long of a break. As for blue-collar, I don't know if factory workers do, but it certainly applies to shop owners, street vendors, and many moped/tricycle drivers.
But you know, when someone gives you a 30 minute break, you take it!