No sweat no cool down

I came back to work for the first time in a week, after Golden Week holidays.

I didn't feel so bad, but my brain doesn't look like work well, and my reports and explanations wasn't as sharp as usual.

It was hot outside typical of early summer, all the same as Golden Week holidays, and I felt my limbs flushed with the heat when I was working on my laptops.
Is it because of the heat, I was suspicious, but something was strange. "No sweat".

I thought that if it were really hot I would sweat and felt uncomfortable with it.
I thought "no sweat, no cool down".

I didn't sweat much probably because it was much drier than mid summer, at the same time I thought that my body was not prepared with the heat of summer and I couldn't produce much sweat, which feel myself feeling hot inside my body.

I've heard once in while that the ability to "sweat well" help us spend hot days.
Having exercises is good to recover this function to sweat well, as well as good to maintain our vitality.