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15 SIDE-EFFECTS YOU MAY EXPERIENCE
(and tips to prevent them)
Do you normally jump on a plane without too much thought about how your body reacts to flying and experience some discomfort on board? Once you are aware of what your body has to deal with and implement some simple strategies to overcome the issues, you will be better equipped to handle a long flight and travel more comfortably, arriving at your destination fit and well.

If you’re about to fly off to an exciting destination across the world, chances are it’s going to be more than a few hours’ flight, and possibly a lot longer. Have you thought about what your body goes through during a long flight when you’re miles high in the sky?
Air travel is generally safe, in fact it’s one of the safest modes of transport. But, the high altitude can wreak havoc on us.
I’ve had to become somewhat of an expert long distance flyer. I love visiting Europe and Asia and living in Australia, far away from most of the world, means air travel time anywhere from 7 hours to 24 hours. So from all my years of long haul flights, I can almost guarantee that you will experience some unpleasantness or discomfort. Cruising at an altitude of 35,000 feet above sea level, as most commercial passenger planes do, is not a natural situation for humans. And doing so for an extended period of time together with a crowd of people in a cosy metal capsule, is going to cause issues.
Firstly, try not to stress, as that won’t do your body any good. Plan your trip to allow plenty of time. Don’t overcommit to a tight schedule. Make certain to take everything you might need.
How your body reacts to flying very much depends on the measures you take to avoid some of the health risks and uncomfortable scenarios that might arise in-flight.

Here are some of the issues that your body may experience when flying which you need to be aware of, and suggestions to help overcome these problems, many of which have aided me on my overseas flights.

1. Dehydration and thirst
The first thing pretty much guaranteed is you will experience dry mouth and dehydration due to the atmosphere of the pressurised cabin, even on short flights. Not only will you feel thirsty, but the cabin air also dries out the mucus membranes of your nose causing nosebleeds, your eyes may feel sore, your lips may start to crack, and your skin may be more than 30% dryer than usual.
The dryness is also due to the very low humidity in cabins, normally at below 20%. Humans are comfortable at around 50-60% humidity.
Tips
Make sure to drink plenty of fluids, preferably water, throughout the flight. Avoid alcohol, as this can make you more dehydrated. Limit your intake of salty foods too.
If necessary, bring a skin moisturiser, eye-drops, lip balm and nasal saline spray. Antihistamines also help unclog sinuses.

2. Exposure to germs
Sitting in close proximity and literally rubbing elbows with strangers for an extended period of time, increases the chance of catching a bug, if someone seated near you is coughing or sneezing. Airborne particles and contaminated surfaces are a given on a plane – tray tables, arm rests, seats, bathrooms. And the plane may not be thoroughly cleaned between flights. However, it is no more risky than any other location where you are close to people.
Tips
I suggest wearing a mask for protection from airborne particles if you don’t want to take the risk of inhaling germs.
You should also carry alcohol wipes and hand sanitiser, wash hands as often as possible, and don’t touch your face.

3. Leg soreness
Cramps, swelling, sore or stiff legs and feet are common problems caused from sitting in cramped conditions with a lack of movement over a long period of time, which results in a build up of fluid in the lower extremities. It’s unnatural for the human body to be sitting for many hours continuously.
Tips
Increase your blood flow and reduce pain and swelling by moving your legs and feet around regularly, flexing, getting up now and then to walk to the toilet, or simply standing for a little while.
Don’t wear tight clothing that can restrict blood flow, and wear comfortable shoes that can be slipped off.

4. Blood clotting and Deep Vein Thrombosis
There is a real chance of developing deep vein thrombosis from a blood clot in your leg or foot, as a result from sitting still in a cramped position for too long. It’s also known as economy class syndrome. Symptoms of DVT include redness, swelling and pain. This can be a life threatening condition and a serious risk for everyone to be aware of.
Tips
To avoid any blood clotting you must change your position regularly. Move your legs and feet around whilst sitting, at least a few minutes each hour – flex, stretch calves, stand a little, walk up and down the plane to the bathroom every couple of hours. It’s important to use the muscles in your legs to help pump the blood.
You can even try wearing anti-embolism stockings which compress your calves to help blood circulate.
Make sure you don’t put hand luggage where it can restrict your leg movement.
If blood clots are a real concern for you, I would recommend choosing an aisle seat if possible, as this gives you a little extra wiggle room and makes it easier to get up more frequently. You can choose your seat beforehand on Seatguru.

5. Tooth ache
You may experience tooth ache thanks to changes in cabin air pressure which result in tiny pockets of gas in fillings.
Tip
Have your teeth checked and fillings attended to before going on a long flight.
6. Bad taste and bad breath
At high altitude, the atmosphere in the cabin can make your taste buds seem a little off and affect your sense of smell, causing you to lose your appetite as well. In fact, you can lose up to a third of your taste buds when flying. That may be why many people find airplane food boring and tasteless.
Production of saliva in the mouth can also be reduced by the lower oxygen level, thus causing bad breath.
Tips
Drink plenty of water, chew gum, brush teeth and use mouth wash.

7. Tired and sleepy
Cabin air pressure reduces our oxygen on the plane and therefore oxygen levels in the blood decrease. This can definitely make you tired and sleepy. Many people fall asleep very easily on a plane due to the change in air.
Tips
Some experts recommend not sleeping during the daylight hours, but I find it best to get some shut-eye when you can, as travelling is very taxing on the body. It also makes the long hours pass more quickly, and you’ll arrive at your destination a happy traveller. Sleeping always helps to increase your immune system as well, which will go a long way to preventing illness.
A pillow, blanket and eye-mask can make it more comfortable to sleep on a plane. Tell crew you don’t want to be disturbed and wear your seatbelt over your blanket.
For optimum sleeping I recommend a window seat because you can lean against the wall, making it a little more comfortable, and you won’t be disturbed with people climbing over you to get out of their seat. Choose your seat on Seatguru.

8. Headache
Headaches and dizziness are also common, due to mild hypoxia from reduced oxygen and dehydration. Sometimes you are hungry and thirsty and if food service has been delayed, all this can definitely make you lightheaded.
Tips
Keep hydrated and have water and a snack handy in your carry-on, as well as some paracetamol.
9. Brain fog and confusion
Speech and thought processes can be a bit muddled during and after a long flight due to less oxygen at high altitude and less oxygen being provided to the brain. You may also feel a bit foggy and disorientated when crossing different time zones and the body doesn’t know if it should be asleep or awake. You may have difficulty making decisions, calculations, and problem solving for a little while.
Tip
Sitting towards the front of the plane where there is more oxygen can help.

10. Anxiety and mood swings
Many people suffer from a fear of flying and feel anxious or have panic attacks about heights, claustrophobia, turbulence, and mechanical failures occurring, in addition to the stress of airports and their hustle and bustle.
Thus, it’s no surprise that these anxieties coupled with reduced oxygen in the plane and being in a confined space with hundreds of people can affect your temperament, make you tense or a bit cranky, myself included.
Mental well-being on a flight is a serious concern as it can affect others around you.
Tips
Consult a health care professional well in advance to flying so you can learn some skills to handle panic attacks and take any necessary medication with you.
Try massaging temples to help calm down. Meditation is a wonderful tool to learn for dealing with nerves. Hold hands with your travel companion. Think positive thoughts. Try controlled breathing. Distract yourself with a task – reading, writing, listen to calming music, watch something funny, chat to a person next to you, drink water or herbal tea, eat a snack, chocolate, lollies, chew gum. These are some of the things that have helped me on flights. Some people find essential oils helpful with anxiety before boarding and dab some on a tissue to smell during the flight.

11. Sore ears and deafness
You may feel pressure in the ears or blockage, as the plane ascends and descends. This can cause pain or worse, eardrum damage.
Frequent flyers can even experience temporary hearing loss or even develop tinnitus from the in-flight noise.
Tips
Usually you can alleviate the pressure in your ears by swallowing, chewing gum, yawning or sneezing, and a popping sensation occurs to clear the discomfort in the ears.
Noise-cancelling earphones can help protect your ears from noise of the plane engines.

12. Radiation
Another health risk of flying is exposure to higher levels of radiation from the cosmic radiation in space. The further away we travel from earth’s sea level, the thinner the air and the less protection we get from the planet’s atmosphere against the sun’s rays.
Don’t panic! Flying is unlikely to increase your chance of cancer. Unless you’re travelling dozens of times every year, then the radiation you are exposed to may start to add up and be of significance to your health.
Tips
Stay hydrated and move around the cabin.
You may wish to take antioxidants which are said to help minimise the body’s stress from radiation.
There is also an anti-radiation blanket you can invest in to protect your body.

13. Gas and bloating
Reduced cabin air can make you gassy. The expansion of gas in the intestines makes you feel bloated and the digestive system gets sluggish. Internal organs get bloated too, making you uncomfortable.
Constipation is also a factor when flying because of lack of exercise, air pressure in the cabin, less access to toilets, and stress from all the other factors mentioned above.
Tips
Avoid carbonated drinks, fatty foods and don’t overeat when you travel. Drink water, eat fibre and try to keep as active as you can.
During your time waiting at airports, exercise a little and make sure to use the bathroom before boarding.
14. Air sickness
Some people get nausea and suffer from travel/motion sickness when flying, particularly during severe air turbulence.
Tips
Try to keep your head up, lean back, avoid moving your head around, look at a fixed point ahead. Don’t read or look down.
Taking ginger tablets or ginger lollies helps, as do travel sickness tablets which need to be taken before takeoff.
Avoiding large meals before flying is also recommended if you think you might suffer travel sickness.
Take a nap on the plane, if possible.
Preferably don’t sit at the back of the aircraft if you are prone to sickness, as motion sickness is greater near the tail. Choose your seat in advance on Seatguru.

15. Jet lag
Most people experience some degree of jet lag after a long haul flight due to the change of time zones, and there is unfortunately no cure for this. It’s caused by the disruption of the body’s internal clock and the circadian rhythms it controls. In other words, flying messes with our normal sleep patterns and puts our body out of sync. Jet lag is how your body resets itself and it can last a few days or even longer, manifesting itself in various ways – gastrointestinal problems, insomnia, lethargy, moodiness and reduced attention span and cognitive abilities.
Tips
Try to immediately acclimatise to the day-night pattern of your destination, for sleep and meals. Sleeping at the wrong time will only prolong the jet lag.

Final thoughts on how your body reacts to flying
How your body reacts to flying is very much dependent on the air in the plane. Thankfully it is filtered constantly, removing much of the bacteria and viruses. Furthermore, about 50% of the air is replaced with outside air many times throughout the duration of a flight. Which means you aren’t likely to catch a communicable disease on a plane, unless someone near you is sick, as mentioned above, similar to being on a bus, train, or theatre. Rest assured the air on a plane is quite safe, safer than in most buildings.
Tell a crew member if you feel unwell or anxious. They are there to assist you and may be able to offer some help in alleviating your health issue.
If you’re after a supplement to help aid your wellbeing on a plane, you may want to look at taking Chlorophyll. It’s full of antioxidants, which help stimulate oxygen to the brain, has anti-inflammatory properties, aids your immune system, as well as bad breath, gas, intestinal functions, energy and more. But please consult your doctor beforehand.

I hope this information has provided you with some insight into how your body reacts to flying and assists you in preparing for future travels.
Make sure to bring things that will make your flight more comfortable, such as a neck pillow, travel blanket, earplugs, healthy snacks, electronic devices and downloaded entertainment, book, music, etc.
Read my Tips for surviving long flights.
Sources and further reading
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So many good tips in this article! The first time I flew, when my legs went a bit numb, I was convinced I was dying because I had never heard of that happening. I wish I had read your article first!!
This is super interesting and it has been quite a while since I have flown. I prefer road trips 😉
This is great info. My legs and back always hurt while flying and I hate it so much!
I haven’t flown since Covid and I honestly don’t miss it! But I do miss traveling to new places.
As much as i miss traveling and getting on a plane, it makes me so tired. These symptoms are real but I love traveling and exploring…
These are great tips! As a frequent flyer, I sometimes forget about doing these things. I wear the compression socks on my long-haul flights and try to walk around the plane every few hours, and that really seems to help my legs.