One thing that does change is that we start sweating sooner as we ride more if we ride hard regularly. Our bodies "learn" to sweat quickly in anticipation as we get fit, much like the fit person starts breathing hard much sooner than an unfit person. (But that unfit person will soon be breathing far harder than the fit one who quickly arrived at his steady state breathing and stays there.)

Basically, our bodies evolve to being able to get into exercise mode very quickly.

BEn