The dominant nostril switches throughout the day. This is called the nasal cycle. Related: Why do we breathe so loudly when we sleep? Although we don't usually notice it, during the nasal cycle one nostril becomes congested and thus contributes less to airflow, while the other becomes decongested.

How long does it take for your nostrils to switch?

It's likely that one nostril will always feel more stuffed up than the other when you're sick. Still, after about 90 minutes to 4 hours, your nose switches sides. When that occurs, you'll probably feel some relief when the swelling in the one nostril goes down—but then the other side will start to feel clogged instead.

Why do my nostrils switch?

Our bodies deliberately send more blood to an erectile tissue between the two nostrils to increase its size and direct the air flowing through one of the nostrils. After a few hours, the airflow switches to the other nostril.