Why Is One Nostril Always Blocked? The Nasal Cycle Explained

Have you ever noticed that one of your nostrils is always more open than the other? That's weird, right?

Have you ever noticed that one of your nostrils is always more open than the other? That's like. That's weird, right? Let's talk about it. Okay, so you've probably noticed this most when you have a cold. So both of your nostrils will be blocked, and then one of them will just randomly open up. It feels like a miracle, but it's actually science due to what's called the nasal cycle. So in addition to having erectile tissue in your pants, you also have it in your nostrils. Every few hours, one side of your nose will experience an influx of blood, which causes that side to swell up and block off airflow. But why does it do this? Oxygen is famously quite good for you, so why would you reduce the amount of it that you can breathe? The answer is actually really simple. And if you've seen my first ever video about colds, you actually already know the answer. See, the cells that line the inside of your nose are a frontline defense against airborne germs. They produce mucus and these little molecular brooms called cilia to trap and then sweep out any of the bugs that you may breathe in. But these cells have to be kept warm and wet. If they dry out, the mucus and the cilia stop working, and you're left vulnerable to viruses. And like I said in that video about colds, the cold in winter can do some serious damage. But having constant flow of any air at all can also dry out your cells. So your nose automatically has your nostrils take turns taking in more air so that one side is always on break. It can relax, warm up, and get all moist again. And the system might also help you smell better. So here's how smell works. Some of the cells that line your nose are neurons. Neurons are in a long chain that lead back to your brain, and they're basically a network of informants about what's going on in the outside world. So the ones in your skin report temperature and pressure. The ones in your eyes report light, and the ones in your nose report chemicals that are in the air. The way different neurons detect these different things is via proteins called receptors. Because they receive information, neurons in your nose have olfactory receptors. So when there's an odor chemical in the air, as the air goes past, the protein will grab onto it and then send a message to the brain. Certain odor chemicals are more grabbable than others. Your nose is naturally more attuned to specific smells, meaning that those olfactory receptors are more sensitive. If airflow is high all the time, only those high sensitivity receptors will be able to grab onto their chemicals as they fly past, the others will get lost in the rush. So if you deliberately slow down airflow on one side, the olfactory receptors on that side will have more time to grab onto those more subtle smells. And having one nostril for loud smells and one nostril for quiet smells will give your brain more of a complete picture of what chemicals are in the air around you. So next time you're frustrated because one of your nostrils seems to just be on strike despite you not being sick. Just be patient. It's taking a break. And don't we all deserve a break?