Here's Why You Wake Up with Morning Breath

We’ve all been there: You wake up in the morning, roll over to kiss your partner, and they lovingly request that you go brush your teeth instead.

It’s the dreaded affliction of morning breath, which is incredibly common—and incredibly annoying. If you’ve ever wondered why you wake up with breath that smells like it could be hauled away on a dump truck, here are six of the most common explanations for arising with stinky breath.

Your mouth produces less saliva when you sleep.

While other factors can contribute to morning breath, this is the crux of the matter—and it explains why no amount of brushing or flossing is guaranteed to prevent morning breath. During the day, our mouths produce plenty of saliva to help wash away the naturally occurring bacteria in our mouths. But when we fall asleep, our bodies slow down saliva production, which creates an environment in which stink-inducing bacteria can proliferate. These bacteria essentially get free roam of your mouth until you wake up and get them in check with your toothbrush.

You’re prone to dry mouth.

If you’re already prone to dry mouth in your waking hours (whether because of medications or simple physiology), then your mouth is likely to get extra dry while you sleep. That’s because your body is already producing less saliva during the day, and that amount of saliva goes down even further at night. This creates an even more hospitable environment for odor-causing bacteria and may increase the pungency of your morning breath.

You snore and/or breathe through your mouth when you sleep.

Regardless of whether you experience dry mouth during the day, snoring and/or mouth breathing can seriously dry out your mouth in your sleep. This results in the same conditions of dry mouth described above: Because your mouth is producing less saliva, bacteria stick around in your mouth unchecked, where they get to work creating odors.  

You’re a smoker.

Smoking tobacco can contribute to morning breath in a number of ways. For starters, it causes your saliva to dry up, which leads to all of the consequences of dry mouth described above. Secondly, it can increase the temperature in your mouth, which makes an even more fertile environment for stinky bacteria. Finally, smoking cigarettes increases the risk of gum disease, which is another big contributor to bad breath.

Your skipped brushing and flossing the night before.

When you skip brushing or flossing, you allow food particles and bacteria to stick around in your mouth. This means that when your saliva production slows down, there will be even more bacteria just waiting to create all kinds of foul odors in your mouth. Regularly neglecting your oral care routine can also lead to gum disease, which (once again) is a major contributor to bad breath.

You have allergies or a cold.

When your head is full of mucus—whether because of allergies or sickness—that mucus will find its way into the back of your throat while you sleep. Once there (brace yourself for the grossness!) the mucus provides a food source for the bacteria in your mouth and throat. This creates a rich environment for these bacteria, which produce stinky odors while feasting on said mucus.

Because there’s nothing you can do about your body’s reduced saliva production during the night, it may not be possible to stop morning breath in its tracks (although proper oral health care can certainly help). But hopefully you can take some comfort in knowing that you’re not alone in suffering from morning breath. In fact, you’re in the good, stinky-breathed company of millions of people waking up all over the world.