Why does my dick shrink during and after a work out?

I work out a a lot and my dick shrinks during a work out. then I go home to take a shower and its still kinda small. I don't even recognize it cuz its a nice size penis. is that normal? is there any scientific explanation to it?

PS: it only shrinks when im doing a lot of running. if im doing weights its nice and normal
Why does my dick shrink during and after a work out?
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