Does oxygen change the concentration of blood?

Answer 1

You may need to rephrase the question.

Concentration indicates the amount of one thing found in another.

Blood is a composite solution of water, salt, cells, proteins and nutrients.

Perhaps you wondered whether these components became more concentrated, that is... there is less water in the blood.

The way to lower water in the blood is by removal in the kidneys. This can be induced through a diuretic (urination inducing agent) such as caffeine or any number of drugs used for high blood pressure. http://en.wikipedia.org/wiki/Diuretic

Oxygen, to my knowledge, does not have this effect.

Another way to increase concentration of components of blood is to increase the contents just mentioned. Here, there may be some confirmation. Athletes performing at very high level will occasionally choose to train for their events in high altitude locations. These areas have less dense atmospheres (they are closer to outer space which has almost none at all). Supplementary oxygen is needed on high mountain climbs such as those conquering Mount Everest.

When the body is deprived of oxygen during exertion over long periods of time, the body generates a greater number of red blood cells, those that carry oxygen. One could say the lack of oxygen has changed the concentration of this one component of blood. This increase in red blood cells indeed does appear to be at the expense of water content. The blood becomes a bit thicker. More background can be found here:

http://en.wikipedia.org/wiki/Altitude_training