The reason comes back
For all intents and purposes, humans should sneeze frequently during the night. Our mucus membranes swell when we lie on our back, stomach, or side; swollen mucus membranes are a common cause of sneezing. However, the body suppresses sneezing impulses through a process known as rapid-eye movement (REM) atonia, which occurs during certain periods of sleep. The neurotransmitters that normally detect allergens and other irritants shut down during REM atonia, thus preventing the involuntary urge to sneeze.
Why Do We Sneeze?
Sneezing, also known as sternutation, refers to the involuntary expulsion of air from the lungs through the nose and mouth. Most sneezes occur due to irritants affecting nasal mucus; sneezing essentially cleans out the nose and throat when these irritants are detected.
The biological process for sneezing is as follows:
- Foreign particles enter the nasal cavity, traveling past the nose hairs before reaching mucus membranes in the nasal passageway.
- These particles trigger the release of histamines, organic compounds that are primarily made up of nitrogen particles
- Histamines irritate nerve endings in the nasal mucus membranes
- The irritation causes signals to be sent to the brain
- The brain redirects the signals to the pharyngeal and tracheal muscles, which create larger openings in the nose and throat
- The sneeze occurs
Sneezing utilizes muscles and muscle groups throughout the body. Common causes for sneezing include:
- Allergens, such as dust and pollen
- Non-allergen particles that still irritate the nasal cavity
- Illnesses, such as influenza and the common cold
- Sudden exposure to bright light, such as leaving a darkened building and walking outside during the day; this phenomenon is known as the photic sneeze reflex, and it affects up to 35% of the population
- Snatiation, a relatively rare genetic disorder that triggers sneezing during digestion after filling meals.
Sneezing is rarely dangerous. However, the expulsion can produce up to 40,000 aerosol droplets that can spread infectious diseases. For this reason, physicians urge people to cover their mouths and nose when sneezing, and to wash their hands with soap and water after the sneezing has subsided.
What Is REM Atonia and How Does It Affect Sneezing?
Sleep in humans is facilitated through an internal timekeeper known as the circadian clock. The circadian clock is based on natural sunlight. A sleep-inducing hormone called melatonin is released at night once the sun goes down; then, in the morning, the melatonin tapers off and the sleeper feels more alert.