Question: Do we have the same amount of air in us when we do exercise as we do when we sleep

Alan Richardson answered on 18 Jun 2013:

The amount gas inside our bodies changes very little whether we are asleep or doing exercise. It is simply the turnover of gas (oxygen) which is important. Clearly during exercise there is a large turnover so we can get oxygen to our cells and keep the amount of oxygen in our red blood cells delivering it at or near to 100%.