I am thinking it has a lot to do with the inevitable mouth breathing due to the reduction in O2 intake....hence the dry mouth, dry teeth, etc. Mouth breathing means that NO is not picked up & added during each inhalation. Nitric oxide is a vasodilator, among other things. https://bit.ly/3mzGRoA

I am thinking it has a lot to do with the inevitable mouth breathing due to the reduction in O2 intake....dry mouth, dry teeth, etc. Mouth breathing means that NO is not picked up & added during each inhalation. Nitric oxide is a vasodilator, among other things.