ears plugging up

[greendragon]

when i train really hard and am pouring sweat, my ears sometimes plug up like underwater or in a bucket. anyone can explain or remedy ?

[BananaMan]

might be the rapid increase of bloodflow that changes the pressure

[Tainan Mantis]

That is caused by the blood pH changing.
I forget the scientific details, though.
It used to happen to me, but now I don't train that hard.
It is good that you push yourself so hard, but you might want to consider that as a sign to start your cool down period.