The turbinates help control air flow by a predetermined pattern of swelling and constricting. The turbinates swell one side of the nose while the other side shrinks. This pattern is called the nasal cycle, and it
repeats itself every 2 or 3 hours, all day long. When the nasal cycle is working properly, we are breathing through only one side of the nose at a time, while the other side rests.
At night, the nasal cycle influences the side of the body you choose to sleep on. You may have thought, or even felt, that fluid flows from one side of your face to the other. In actuality, fluid from one side of your nose cannot move to the other side through the septum. Instead, you’re experiencing the nasal cycle at work. Some scientists believe that the nasal cycle is what causes most people to turn from side to side when they sleep. Others argue that turning is what causes the nasal cycle to occur. However, we do know that the nasal cycle occurs even when you are wide-awake and standing. So day or night, we breathe through one side of our nose at a time, and it alternates from side to side. The nasal cycle is natural, so most people do not realize their breathing is asymmetric unless there is underlying nasal obstruction.