The Science Of Avoiding Getting Sick On Your Next Flight

Taking a flight is an exciting experience, even if you're a first-time flier — if so, here's how to not make these rookie mistakes. But it's also a terrifying thing if you stop to consider exactly what you're doing. A plane is essentially a tube of metal that hurtles through the air thousands of feet above the ground at mind-bending speeds. And if you fly on the worst days of the year, taking to the skies can also be infuriating. But look past those obstacles, suspend disbelief momentarily, and the world of commercial flying becomes a blessing to anyone who likes to travel. 

It can take us to places near and far in a heartbeat, and open up new destinations, with ridiculous ease. Unfortunately, with those benefits, flying also poses health risks. A passenger is cooped up for hours with total strangers, dependent on a closed-air system that circulates recycled air and has to use restrooms that are as salubrious as the average public toilets. It sounds like a recipe for a health disaster, but there are ways to avoid getting sick. Follow these pointers, and you should emerge from your next flight fighting fit.

To not get sick, it helps to keep your immune system running at full strength. You can certainly help your immunity by being rested before the flight. If you aren't, then your immunity system will be compromised, and you will be more prone to getting sick onboard. According to the paper "Sleep and immune function," published in 2011 in "Pflügers Archiv – European Journal of Physiology," sleep and the normal patterns of our circadian clock are critical in keeping our immunity in check. 

While it is perfectly normal to get excited before a trip, to anticipate what you'll do when you get to the destination, you shouldn't let this get in the way of your sleep. Starting a few days before the flight, resist the temptations of late-night dinners, or drinks with friends, midnight movies, or wild night clubbing. Go to bed at a reasonable hour, and let your body charge up. After all, there will be plenty of opportunities to let loose when you get to your destination — provided that you don't get sick on the way.

There is another way of boosting your immune system that doesn't involve long periods of slumber. That option is zinc, either through diet or supplements. Some fliers swear by this method as a way to boost their immune system, and while not everyone is convinced by the efficacy of zinc in increasing immunity, there is science to back up the assertion. Zinc has been noted for its role in the efficient running of the body's immune capabilities, a process outlined in the paper "Zinc as a Gatekeeper of Immune Function," published in the scientific journal Nutrients. 

While the exact link isn't fully understood, what is established is that the ions of zinc help in the regulation mechanism within immune cells. Dosage suggestions for adults, as per WebMD, is around 11-12 mg per day. Others also laud the effects of Vitamin C, a position that is also supported by science. The vitamin also assists cellular procedures in the immune system, as noted in the paper Vitamin C and Immune Function.

Looking at the findings of the Airline Water Study 2019 conducted by Hunter College New York City Food Policy Center, many airlines have water onboard that is not fit for consumption. Scouring water data pulled from various sources, including government violations, it found that only a few of the more than 20 national and regional airlines in the country had water that could be considered safe. Some of the data analyzed included reports of water samples that found traces of E. Coli. 

The study suggested that passengers should only drink water that comes from a sealed bottle, but consider this — do you know the length of time that water has been sitting in the bottle, and where it has been stored? Plus, a 2019 paper published in the Journal of Water and Health found that microplastics fell into the water of a plastic bottle every time the screw cap was opened and closed. A better option is to fill your own bottle at a filtered water station in the airport, which is also better for the environment than drinking water from a disposable plastic bottle.

Bacteria and viruses are sneaky. They can latch onto you with consummate ease, work their way into your respiratory or blood systems without detection, and get you sick with the efficiency of a trained assassin. But they can't generally travel large distances, so the closer you are to a person carrying a bacterial infection or viral illness, the greater your chances are of catching it. So, the best way to not catch something from another passenger, whether they seem sick or not, is to keep away from them. 

A study published by the Wake Forest School of Medicine published in the Journal of Infectious Diseases in 2013 found that people with flu could send viral particles up to six feet away. During the COVID-19 pandemic, the Centers for Disease Control (CDC) suggested that people stay at least six feet away from each other, a provision that became known as social distancing. So when the pre-boarding announcement blasts over the speakers at the gate, don't rush to join the mad crush of passengers that will spend the next 10 minutes going precisely nowhere. Wait until everyone has boarded and leisurely walk on — it's not as though somebody is going to take your seat, so what's the rush?

Sicknesses are very good at burrowing into our bodies via the mouth or nasal passage. An easy way to block that simple immigration route is to wear a mask. As the Mayo Clinic outlines, a face mask has been shown to reduce the spread of a virus, simply by supplying a physical barrier to the virus. But for this method to be effective, the mask needs to be of a certain quality. 

The class of masks known as N95 have become commonplace across the U.S., and have the capability of shutting out both large and small air particles that the wearer might breathe in. The designation of N95 refers to the filtration capacity of the mask, in that it can block out a minimum of 95% of particles in the air. This, of course, is crucial in the fight to avoid infection, because the more virus you can keep out, the better your chances of not catching anything. Cloth masks also help but aren't usually as effective as a well-fitted N95 that cinches around the nose and fully covers the mouth.

While masking is helpful, perhaps a more crucial tool in the war against getting sick — not just on a flight but anywhere — is washing your hands with soap and water. As the CDC notes, a majority of diseases are transmitted from person to person when neither of them washes their hands using running water in concert with soap. It seems like such a simple way to combat illnesses that travelers might not think it's particularly effective, but the truth is that it is. 

The CDC mentions that respiratory illnesses, which include the common cold, can be cut by about 20% if everyone just washes their hands with soap and water. If those common cleaning mediums aren't available, you can use hand sanitizer, making sure it has an alcohol level of at least 60%, as recommended by the CDC. But be aware that even the CDC concedes that hand sanitizer is not as effective as the act of washing.

As mentioned earlier, the mouth and nose are key ports of entry for infectious particles. So are the eyes. We might not realize this, and most likely do it subconsciously, but we all touch our mouth, nose, and eyes with our hands repeatedly throughout the day. Maybe you are doing it while reading these words? In a 2015 paper published in the American Journal of Infection Control, scientists carefully analyzed 26 medical students at the University of New South Wales, in Australia. 

Special attention was placed on the amount of times that they touched their faces, and the results were startling. Every one of the subjects in the study touched their faces more than 20 times per hour, and almost half of the time the touches were in areas with a mucous membrane — the nose, mouth, or eye, places where bacteria land before heading to their final destination. On a plane, where large numbers of people are crammed into a tight space, the proliferation of bacteria is hard to overstate. This is why, on a plane, you should definitely avoid touching your face.

For some posters on Reddit, flushing out their nostrils before or after a flight pays dividends. The benefits seem fairly obvious. Rinsing the nasal passages can add moisture to the inside of the nose, which helps during and after a flight since airplane cabins are notoriously dry. The flushing process also does what it sounds like it should do — it washes away germs that are cultivating in the nostrils. 

The build-up of mucus and pathogens in your nose can make you feel bunged up, or even give you a runny nose, and while it might not lead you to sickness, it might make you feel rundown or leave you with a stuffed nose. This method of sinus rinse typically uses saline water (never water from the tap) and, according to the Cleveland Clinic, can be effective in combating not only things like colds but also sinus infections and respiratory issues. Keeping your sinuses open, and free from obstruction, will help you breathe more easily, and make you less prone to getting an infection.

Just before you board your next flight, have a look around at all the other passengers getting ready to get on the plane. In fact, look at every passenger in the airport. Now look at their shoes, and imagine where those boots, pumps, flats, stilettos (something, incidentally, that you should never wear on a plane), sneakers, and sandals have been. Would you rub your hands all over the bottom of their soles? Yuck, nasty! 

And yet, in effect, that's what you will be doing if you put your bag on the floor under the seat in front of you. Because that piece of aircraft real estate is where thousands of pairs of shoes have rubbed their soles. Bits of dirt, grime, and all the bacteria that they contain are just waiting to stick themselves onto the next surface that they touch. Do yourself a favor, and place your bag in the overhead bin, one part of the cabin that you can be fairly certain doesn't get trampled on by passengers' shoes.

As anyone who has flown can attest, planes have very dry air — about 50% the humidity of air that we are used to, according to one estimate. That means you can easily feel parched, dehydrated, heavy-headed, and generally fatigued. More than half of the human body is water, so not having enough inside us can have serious effects on our health. If we are low on it, keeping our body temperature constant might become a struggle, digestion can be compromised, and our brain might become foggy. 

And when we are sick, or worried about getting ill, as the blog for the Canadian Digestive Health Foundation notes, hydration is key for ensuring we don't suffer. Hydration will keep our mucus membrane functioning properly as an obstacle to bacteria and will ensure that our nasal passages don't get too dried out and become sensitive to the slightest piece of dust or airflow. And with adequate hydration on board, you'll just feel better, which is half the battle to not getting sick.

When arriving passengers disembark from a plane, a cleaning crew swoops in to prepare the cabin for the next set of fliers. The cadre of cleaners is usually on a tight schedule, given minimal time to get the cabin in a fit state for the next legion of vacationers. Sometimes cleaning is done in as little as 10 minutes or less, and if you think about what can be done in that brief interlude, across multiple rows of seats, then it becomes pretty obvious that it isn't a deep clean. 

If you've flown enough, then chances are that you have come across various pieces of detritus still inside the seat pocket, dried, crusted food caked onto the food tray, or stray hairs still valiantly clinging to the top of your seat. This is where sanitizing wipes come in handy. They will kill all germs left by previous passengers and should be used on and around the seat, on the tray table, and even on the screen in front of the seat. Basically, any surface that another passenger could have put their hands on.

By now, it should be evident that staying away from other passengers is the most effective way of avoiding their germs. But on a plane where every seat is taken, you can't escape all the other people onboard. You can, however, minimize your exposure to them by choosing a window seat. Passengers in aisle seats, by dint of their location within the cabin, come into contact with other passengers more, which means they are more exposed to the bacteria of others.

A study from 2013 published in Proceedings of the National Academy of Sciences sheds further light on this theory by looking at the movement of passengers on several transcontinental flights. They found that 80% of people in aisle seats left their seats during the flight, while the figure for passengers in window seats was about half that. The data also showed that people seated furthest from the aisles — namely those at the windows — had less contact with other passengers than those in aisle seats, who had the highest. Less contact translates to fewer opportunities for bacteria transmission. Another bonus of a window seat is that they are the best seat to book if you need to get work done.

If you've taken a flight across the country, to another continent, or maybe one of the longest flights in the world, you might have noticed that the state of the restrooms tends to deteriorate throughout the journey. This is not surprising, since only the cabin crew is tasked with keeping it clean, and they have plenty of other responsibilities to take care of, including difficult passengers, one of the absolute worst parts of the job. Since the toilets, at least in Economy class, are used by so many people, some of whom definitely don't wash their hands, they rapidly become breeding grounds for bacteria. And if all this wasn't bad enough, consider the industrial-strength mechanism of the toilet flush. 

A 2022 paper published in Building and Environment measured the aerosol effect of particles in the toilet bowl caused by the action of the flush, noting that feces, spit, and vomit were all substances that make their way into the toilet bowl during a typical flight. What the paper found is that the dual actions of the water rinse and the whooshing vacuum suction that empties the bowl combine to spray aerosols of the bowl's contents into the air of the toilet. So whatever was in there before the flush diffuses partially into the toilet's atmosphere afterward. The CDC warns that airplane toilets are often where people come into contact with feces that can give passengers norovirus, among other illnesses.

While some people think it's funny to call a flight attendant a trolley dolly — it's not — the fact is that they do serve passengers food and drink. That means that whatever illness they have can easily be spread to you. While cabin crew generally won't fly if they are really sick, some will fly if they have the sniffles, or are contagious even if they have not developed any symptoms yet. If you avoid eating a meal or getting a drink from them, you have less chance of interacting with any bacteria that they are hosting. 

Beyond that, there is also the undeniable issue of the food itself and how safe it is to eat. A paper from 2020 that was in the journal Travel Medicine and Infectious Disease described how food served in planes falls under variable hygiene requirements, guidelines that are markedly less strict than those put in place for physical restaurants. The paper also questions the lack of standards in food regulation for aircraft meals, and points to this as a potential cause for food poisoning of passengers.

For one poster on Reddit, a warm shower is the perfect tonic for staying well after a flight. The shower will help clear out the sinuses, and can also wash away any germs still stuck on the body, or clinging to the hair of the passenger. However, the shower doesn't have to be hot.

The most effective method of getting rid of germs is washing in water, and this could be cold or hot water, it makes no difference. That said, it might make a difference to you. After all, following a flight when you have managed to dodge all the potential bacteria hurtling at you from all angles, what sounds more relaxing — a hot shower or a frigid plunge?