I still breathe normally through both the nose and mouth when using it. And the effect is good enough from just warming the (bigger) airflow through the mouth.

I still breathe normally through both the nose and mouth when using it. And the effect is good enough from just warming the (bigger) airflow through the mouth. But it probably stings a bit more in the nose compared to the mask variants. I don't feel it hampers my breathing at all, really. If anything, it allows me to take full breaths in conditions where that normally would hurt. I got the sports variant.