Just one sneeze is sufficient to expel mucous and saliva laden with bacteria an average of 40 meters into the air with the potential to infect all who inhale it.
Sneezing travels far and spreads infection and disease
The scientific name for sneezing is ‘Sternutation’. Simply described, sneezing is the expulsion of air through the nose and mouth which often brings with it droplets of saliva and mucous, laden with viruses and bacteria, which can hang in the air for several hours in the right environment and able to infect others if the atmospheric conditions are right.
The nose is lined with fine hairs designed to trap small particles which might be inhaled and cause irritation in the nostrils. The sneezing reflex is activated when something tickles or irritates the nerve ending in the nostrils. This irritation sends a signal to the brain, which in turn releases histamines into the system, eventually manifesting as a slight burning sensation in the nostrils creating a chain reaction. This in turn triggers a reaction in the throat, face, eyelids, abdomen, lungs, and mucous membrane in the nose, culminating in a sneeze to expel the irritation.
A single sneeze, on expulsion, can travel at a speed of 95 miles per hour, however, it can be up to 630 miles per hour, under the right conditions and can release at least 40,000 droplets, which go some way towards understanding why sneezing has been sited as the commonest way to spread airborne infections.
The distance which a sneeze can travel depends on several factors working together at the same time. Firstly, it depends on the wind speed and the direction, humidity, temperature, pressure, elevation, and the strength of the person who is sneezing. However, it is believed that a single sneeze can travel up to 40 meters on average, but if wind-assisted it can travel substantially further, with larger droplets dropping off after being airborne for between 2 to 3 meters. Therefore the more refined the droplets the greater the traveling distance.
Sneezing can be embarrassing and often sneak up when least expected and for this reason, some people try to stifle their sneeze, which research has shown can be dangerous. This can cause irreparable damage to the sinuses, rupture the inner ear and nasal cartilage, and in extreme cases, damage even to the brain, this is because the backdraft a sneeze creates can be extremely forceful.
Nasal irrigation is not the only reason to trigger sneezing. Millions of people worldwide suffer from a sneezing condition known as photic sneeze reflex, which is a condition due to the malformation of the trigeminal nerve. With this condition, several sneezes can be triggered, one after the other simply by stepping into the sunlight, inhaling cold air, or a strong smell.
One of life’s mysteries is why is it not possible to sneeze without closing the eyes. One theory has it that the automatic closing of the eyes is a reflex action to protect them from the escaping mucous through the nose and mouth. Sneezing is one of the principal ways of spreading disease; therefore it is worth remembering that whenever possible the nose and mouth should be covered when sneezing to prevent as far as possible the spread of viruses and bacteria.