Hay fever season is almost upon us, and as well as itchy eyes and a blocked nose we're likely to be doing a lot more sneezing as the pollen count creeps up.
But when you think about the process of an unexpected sneeze, it feels a little strange...
That tell tale tickle in the nose has you scrabbling around for a tissue before you let out an almighty achoo!
Unless of course you try to stop your sneeze coming – which is actually not a good idea, but more on that later.
While you may not have given much thought to why you sneeze before now, it's worth knowing why we do it as there are actually some pretty important health benefits to the process.
Here's everything you need to know about sneezing from why we do it, to how it's good for us and the reasons you should never hold one in.
What happens to the body when you sneeze?
While a sneeze starts in the nose, sneezing itself is actually a pretty complex interaction between the nose, the brain, and the various muscles throughout your body.
"A sneeze is a reflex (involuntary) act and is triggered by something that irritates the lining of the nasal passages, starting inside the tip of the nose to inside the back of the nose," explains Dr Stuart Sanders, GP at The London General Practice.
"This could be a virus, a bacterium, an allergen such as grass pollen, or an irritable inhaled substance such as chlorine."
The mechanism is as follows:
1. The irritant lands on the nasal lining (mucosa).
2. The mucosa sensors sends a sensory message to the brain.
3. The brain recognises and processes what is happening.
4. The brain sends a message to the chest and diaphragm to take a deep intake of air.
5. The brain sends another message which simulates a sharp exhalation through the nose – resulting in a sneeze.
Interestingly, particles in the air aren't the only triggers for sneezing. According to one study more than 35% of us sneeze when suddenly exposed to a bright light – a phenomenon that's commonly known as photic sneeze reflex.
Although the reason sunlight causes some of us to sneeze isn't fully understood by science, most experts believe that crossed wires in the brain are probably responsible for the photic sneeze reflex.
Health benefits of sneezing
While the post-COVID era has everyone on high alert around a germ-spreading sneeze, there are actually some pretty important health benefits to achoo-ing, including ridding the nose of unwanted irritants.
“Sneezing is about getting rid of an irritant from the nose," explains GP, Dr Nisa Aslam from Puressentiel.
"Irritants are broad ranging and include allergens like pollen, a viral infection, house dust mites, indoor and outdoor pollution, dry air or a change in temperature.”
Watch: Five natural ways to help treat hay fever
This makes sneezing an important part of the immune process.
"It protects the body by clearing the nose of viruses, bacteria, dust and pollen," Dr Aslam continues. "Immune health is also linked to respiratory health."
Put simply, if we didn’t sneeze, our bodies could allow potentially damaging substances into our sinuses or lungs.
Why you should never hold in a sneeze
As we've already explained, sneezing is an important process which allows waste to exit through your nose, so stopping yourself from sneezing, say by holding your nose, means all the harmful pollutants and bacteria that your nose has filtered will remain there.
Sneezing is also a powerful activity, with a sneeze capable of propelling droplets of mucus from your nose at a rate of up to 100 miles per hour!
And trying to stem your sneeze greatly increases pressure inside the respiratory system to a level of about five to 24 times that caused by the sneeze itself.
Experts say holding this additional pressure inside your body can cause potential problems, including eardrum ruptures.
"As the air pressure in the back of the nose rises when a sneeze is held in there is a risk of pushing mucus and infection into the middle ear," explains Dr Sanders.
"This could cause acute deafness, infection (otitis media) or even rupture of the ear drum in excessive circumstances."
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If you don’t sneeze, mucus can accumulate and be forced back into the Eustachian tubes. Eustachian tubes are small passageways that connect the throat to the middle ear.
These tubes are normally closed but can open during an explosive sneeze pushing infected mucus back in and potentially causing a middle ear infection.
Dr Sanders says the increase in pressure caused by holding in a sneeze can also force infection into the paranasal sinuses potentially leading to acute sinusitis.
"The sinuses are situated close to the nose, usually air-containing cavities with open connection with the nose," he adds.
As well as the risk of infection, there are some other potentially damaging outcomes holding a sneeze can lead to, including throat damage.
Doctors have found at least one case of a person rupturing the back of their throat by holding in a sneeze. The 34-year-old British man said he felt a popping sensation in his neck, which began to swell, after he tried to hold in a sneeze by closing his mouth and pinching his nose at the same time.
Although extremely rare, this is a serious injury requiring immediate medical attention.
So, while it might be tempting to try to stop yourself letting out a giant sneeze, it's important not to stop your body doing its job.
Just make sure that when you do sneeze, you do it considerately, which means doing your best to cover your mouth and nose while you're letting it out.
Also, be sure to wash your hands thoroughly and wipe down nearby surfaces once the sneeze bomb is over.