Breathing slows when you sleep, so it's normal for your oxygen level to drop, but it should remain in a healthy range. In ...

The gas transfer is assisted by respiration (breathing in and out). The body needs to constantly expel the carbon dioxide-rich air and bring in fresh oxygen-rich air, and this is done by changing ...

In order to supply more oxygen to the exercising cells, the body increases the rate and depth of breathing. The time taken for the breathing rate to return to normal is known as the recovery time.