No— it’s supposedly impossible for humans to sneeze while they’re sleeping. Although no study has been conducted to confirm this, most sleep experts and neuroscientists agree that it just can’t happen.
Sneezing is what’s known as a “reflex action.” To perform a reflex action, the brain requires a lot of activity and stimulation. When we fall asleep, our bodies enter paralysis— which extends to our reflex actions. This means that even if you dream that you are sneezing, you won’t be able to sneeze for real.
In order to understand why it’s impossible to sneeze in your sleep, you’ll need to know why we sneeze in the first place.
So, why do we sneeze?
Sneezing is your body’s natural response to stimulation, irritation, or light. While there are a variety of things that can trigger a sneeze, the act of sneezing itself is involuntary. Some of the reasons why your body may trigger a sneeze are:
- Allergies - Hay fever or an allergy to pollen, mold, dander, or dust can trigger a sneeze.
- Foreign particles - These are non-allergens that can still irritate your nasal cavity and cause sneezing.
- Illness - Influenza, the common cold, and just feeling under the weather can trigger a sneeze.
- Light - Only some people experience this, and it’s known as the photic sneeze reflex. Sudden light exposure can cause certain people to sneeze.
- Snatiation - This is a relatively rare genetic disorder that triggers sneezing during digestion after large meals.
A sneeze is an uncontrollable physical response to an outside stimulus. When something, say a piece of dust or a strong odor, stimulates nerve endings in the lining of the nose, the stimulus travels to the central nervous system and is then routed back to the muscles of the face, throat, and chest. Once stimulated, these muscles go to work and cause us to forcefully expel air from the mouth and nose. This is what’s known as the sneeze.
Why can’t you sneeze in your sleep?
Although we should be more prone to sneezing while asleep— as our mucus membranes swell when we lie down— the reduction of airflow and movement while we sleep doesn’t stir up dust or other particles. Therefore, the membranes don’t come into contact with any irritants as they do when we’re awake.
Some people assume that if they were to sneeze in a dream, they would sneeze for real and wake themselves up. However, this is not the case. When we fall asleep and our body enters REM (the dreaming phase) our muscles become paralyzed. This is your body’s way of protecting you from any injuries caused by sudden movements while you sleep. This paralysis also extends to your reflex muscle actions, preventing you from sneezing while you snooze.
Also, during the REM phase, certain neurotransmitters are shut down (REM atonia), resulting in motor neurons not being stimulated and reactive signals not being sent to the brain. So, even if various stimulants and irritants were surrounding you while you sleep, your brain wouldn’t be alerted.
Some people, such as those with severe allergies, may be woken up by a sudden urge to sneeze. They may mistake this as sneezing while they’re asleep. This isn’t the case. You’re simply woken up by an urge to sneeze, not by the sneeze itself. The body must come out of paralysis before your muscles can move and perform reflex actions. When this happens, it’s often so brief that you probably won’t remember it.
However, constant disruptions to sleep due to urges to sneeze can result in daytime sleepiness. You can reduce the urge to sneeze by keeping your bedroom clear of airborne contaminants, such as pollen and dust mites. To further reduce the presence of irritants in your bedroom, wash and vacuum your sleep space regularly. You can also use an air purifier to help remove allergens, bacteria, and other toxins from your bedroom.
Do we cough in our sleep?
No, we can’t cough in our sleep either. This is because the same biological process that prevents sneezes while you’re asleep also prevents you from coughing. Sure, it’s possible to have a cough during the night, if you’re under the weather, suffer from asthma or allergies— but you’re definitely awake when you’re doing the coughing. Similar to sneezing, it is more than likely that you’ll be awoken by a sudden urge to cough while you are sleeping. At this point, your body will wake up and paralysis of the muscles will cease, allowing you to cough.
A common misconception is that babies and young children can sneeze and cough in their sleep, but this isn’t the case. Regardless of age, the person would need to awake to make any reflex actions, such as coughing and sneezing.
Sneezing and coughing aren’t the only urges that are suppressed by sleeping, some others include:
- Hiccups - These occur upon awakening. They’re usually caused by gastrointestinal reflux. This is when the sphincter valve is not working correctly, disturbing the stomach contents. When the stomach acid hits the lining of the esophagus it causes irritation and possibly spasm.
- Urination/defecation - While these actions are technically possible while we are asleep, it isn’t supposed to happen. If this is occurring in adulthood, it’s likely a sign of something more serious.
Despite a lack of scientific research and investigation— it’s safe to assume that you can’t sneeze in your sleep. If you feel that you or someone you know may have experienced sneezing while they’re asleep, the likely reality is that they were awoken by the urge to sneeze, and not the sneeze itself. To reduce the risk of being awoken by a phantom sneeze during the night, you should ensure that you’re getting an adequate amount of sleep. This will ultimately reduce your risk of catching viruses and infections, particularly the ones that linger and cause those bedtime sniffles.