so ur saying a bigger intake of oxygen does nothing for u? i find this to be completely wrong.
Well, its kind of like pouring water into a class in the bottom a full swimming pool.
The average Saturated Percentage of Oxygen (SPO2) in the healthy body is 94-100%. Basically, that is the measure of how much oxygen is attached to the hemoglobin on your red blood cells. It is measured using a pulse oximeter. If you put yourself on 100% pure oxygen, you can only max out your SPO2 to 100%. the rest is just breathed out. You can prove this by blowing through a lit cigarette and watching the flames shoot out (very dangerous, but really neat to see).
Now, lets look at the oxygen delivery system. In an O2 bar, the usually use a nasal cannula (2-pronged hose that fits into your nose). We use those same things in the medical field. From the O2 tank it all the way to the end of the cannula, it is 100% oxygen, but once it leaves there, it mixes with room air (~21% O2) and then you breath it in. Now, depending on the flow, a nasal cannula will yield an inhaled breath of oxygen from about 24% at 1 liter per minute (Lpm) to 40% at 8 Lpm. Above 8 Lpm and you start drying out your nostrils (above 15 Lpm and they flap really hard). To get close to 100%, you either have to use a non-rebreather mask or a Flow-Restricted Oxygen Powered Ventilation Device (FROPVD), which I seriously doubt you will find at an O2 Bar.
It will help with a hang-over because your brain needs 3 things to function: 1) oxygen, 2) sugar, and 3) a medium to transport #1 & #2 (ie blood). Drinking alcohol all night will dehydrate you, thus lowering the amount of fluid in the blood flowing through your veins, which makes it harder for it to transport O2 to your brain. Having a little extra O2 will help with the headache. It will not, however, help you sober up while you are drunk... I know this for a fact! LOL!!!