@mur2501 @wauz The climate heat has probably a big role sure. But the big thermal change is generally not good for the body. It need to work more to take again its temperature in good working state. The air cooler are what made me generally sick (take cold, not travelers' diarrhea) when I go in Asia. My wife that is Chinese start it every time, if I'm alone I stop it. I had few times travelers' diarrhea. I'l lucky enough at It least during 2 or 3 days and gone away. I sometime drink fresh water from tap in Chinese big cities, all Chinese say that's dangerous and don't do this themselves, but I never get sick of that.