Yes, we always have a little bit of nitrogen in the system (that is normal because 3/4 parts of air are nitrogen). This is not a problem normally, but it becomes one when we get inside the water. Have you ever been scuba-diving? when we get inside the water there is a different in pressure (you can feel it in your ears when you are diving). This has an effect on our capability of absorbing different gases and…guess what: it makes the levels of nitrogen in our blood go up! as a result, people can get quite dizzy. This is know as “nitrogen narcosis” because it makes people sleepy (almost like anesthesia).