Anyone who has shared a room with another person knows that nighttime sleep is punctuated with lots of sounds and snuffles. However, you might be wondering, “Can you sneeze while sleeping?” Let’s explore the science of why research seems to reveal that you cannot sneeze in your sleep, but sneezing can occur in brief wake periods during certain sleep stages.
What Causes Sneezing
Sneezing begins when irritants stimulate the lining of your nose, which releases a chemical called histamines. Part of why “antihistamine” medications work to suppress sneezing is that they reduce these histamine particles.
However, the presence of histamines triggers nerve endings that send signals to your spinal cord, where a sneeze reflex is triggered if enough stimulation occurs. Sneezing is a coordinated muscle response intended to expel the irritants that triggered the sneeze in the first place.
What irritants can cause sneezes? Here are some:
- Dust, pollen, and other small particles in the air. Particulates can cause sneezes if there are enough of them, but allergens, like pollen, are more likely to stimulate sneezes.
- When you are sick with a respiratory-affecting illness, like a cold or flu virus, your sneeze reflex may be triggered more.
- Other conditions, like walking into a bright space suddenly or while digesting your food, prompt sneezes in some but not all of the population.
People ask if you can sneeze in your sleep specifically because it is a fairly excitatory response, but, logically, irritants could reach your nose while sleeping, just like when you are awake.
How Does Sleep Prevent Sneezing?
Answering the question of whether you can sneeze while sleeping requires understanding sleep’s structure.
Sleep occurs in four stages, three of which (Stage 1, Stage 2 and Stage 3) are considered non-REM sleep, with REM sleep being the deepest stage. REM sleep is when your body goes into a state known as atonia. This state represses muscle movement and temporarily stops motion in most of your muscles (though, as rapid eye movement is what REM stands for, your eyes do continue moving). When you’re in REM sleep and experiencing atonia, the triggers that would typically start the sneeze reflex aren’t triggered, so irritants aren’t expelled. This state is thought to contribute to why mild irritants that could cause sneezes in the daytime don’t trigger a sleep sneeze.
There is no atonia during non-REM sleep. Your body is still repressing many urges during non-REM stages to maintain sleep, just not as thoroughly. Environmental factors are also helpful for avoiding sneezing during non-REM sleep: after all, if the environment wasn’t making you sneeze when you went to bed, your circumstances don’t change much while lying down in a single room for the night. However, a strong enough stimulus may prompt a sneeze when you are in non-REM sleep. This stimulus, however, would also trigger you to wake up, so it is still truly not a sleep-sneeze.
When you wake up because of a single sneeze, you may remain conscious only long enough to sneeze and not retain a memory of having woken up. However, if you are experiencing a cold or the flu, your sneezing may interrupt your sleep more often, causing you to get a less restful night of sleep with more time in stages 1, 2 and 3, rather than in REM sleep.
Does Sleep Also Suppress Coughs?
Now, “can you cough in your sleep?” The answer is also no. Your body wakes you up when you cough, which results in more light sleep or less sleep overall. This is the part of the reason people don’t feel well-rested when having colds or the flu. Sleep generally suppresses coughs, but just like what happens with sneezing, you will wake up to cough when the stimulus is strong enough. REM sleep cannot be interrupted by a cough. But if coughs keep waking you up during non-REM stages, you are likely to get less REM sleep overall.
So, can you sneeze in your sleep? The short answer is no. Sneezing at night is more likely to occur as a brief period of wakefulness during a light stage of sleep, perhaps without you waking up fully and registering that you ever were awake in your memory.
The way that sleep functions means that during the REM stage, your body prevents responses like sneezing. However, during non-REM sleep, your body’s dampened reactions to stimuli that would typically make you sneeze may still allow a sneeze in some cases, like a strong allergy. But this would wake you up briefly, so too much sneezing at night may make it harder to feel well-rested in the morning.
Sneezing in bed can be due to accumulated dust or other particulates in your sheets, pillow, or mattress. There can also be particles that stimulate your sneeze reflex in the air. During a cold or flu, sneezing is stimulated by the combination of being horizontal and having more mucus flowing than usual and any allergens or irritants present.
Lying down sends more blood to the head, where larger blood vessels can constrict airways, making your nose feel stuffy when there is no additional mucus. Also, mucus from post-nasal drip can pool when you are horizontal, resulting in a feeling of more mucus clogging your airways.
You’ll sneeze less often at night if you clean your sleep environment of pet dander and dust regularly. The typical cleanup should include washing the sheets, vacuuming the floor and cleaning pillows and mattresses. You may also want to consider getting a new mattress with hypoallergenic materials.
One of the reasons is that mucus pools when you are horizontal and stimulates your reflex to cough and expel the post-nasal drip mucus. Dry coughs can also occur more often if you are mildly dehydrated and feel like your throat is parched.