Holiday time is fast approaching. Whether, like me, you are about to take off on your travels or you are looking forward to a well-earned break later in the summer, I thought it would be an opportune time to look at the effects flying has on our bodies.
Pressure, temperature and oxygen levels in an aircraft cabin fluctuate, and the humidity level is lower than it is at sea level. All of those things can interfere with some of our body’s normal functions.
The longer the flight, the greater the effects on our bodies. Generally, a flight time of longer than six or seven hours is seen as long haul, which brings in flights to the west coast of the US and Canada. And of course, flying to southeast Asia and beyond opens up the possibility of 12 hours inside the cigar tube of an aircraft.
So what symptoms might you notice when flying and what can you do to lessen the effects?
Dehydration
This is common on long-haul flights and explains why your throat, nose and skin can feel dry on an aeroplane. Aircraft cabins have very low humidity levels, because about 50 per cent of the air circulating in the cabin is pulled from the outside, and at high altitudes the air is almost completely devoid of moisture.
What you can do
To stay hydrated, pack an empty water bottle in your carry-on that you can refill after going through security and take with you on the plane. Wear glasses instead of contacts to help prevent discomfort to the eyes. Restrict your alcohol intake as it acts as a diuretic (increasing fluid loss).
Ear problems
As the pressure in the cabin changes, the air pressure inside your inner ear tries to adjust. When the outside pressure changes quickly during take-off and landing, this may cause earache. We often notice our ears “popping”, which is a sign the pressure in the ears is equalising. And the same pressure changes can also make our bellies bloat.
What you can do
Swallow or yawn to open the Eustachian tubes, which control the pressure in the middle ear, during take-off and landing. And to minimise the risk of motion sickness, choose a seat over the wing, where the degree of motion is lowest.
Risk of infection
You might think that recirculating air in the cabin would make you prone to getting an infection, but modern aircraft have advanced filtering systems that remove most bacteria, fungi and viruses from the air. In fact it’s proximity to fellow passengers that poses the greatest risk. We became all too aware of this when Covid-19 emerged and airlines introduced mandatory mask-wearing during flights.
What you can do
Make sure you are up to date with Covid vaccination. Wear a mask during the flight. And carry a small bottle of hand sanitiser with you, so that you can wash your hands thoroughly and wipe tabletops clean.
The risk of a blood clot
Blood clots are associated with being immobile for long periods. They usually start in the leg (deep-vein thrombosis) but can spread to the lungs as pulmonary emboli. According to recent research, combining data from 18 studies, the longer you travel, the greater the risk of blood clots. The authors calculated there was a 26 per cent higher risk for every two hours of air travel, with the increased risk starting after four hours. Separate research found the incidence of symptomatic DVT in the month after a flight lasting more than four hours is one in 4,600 flights.
What you can do
Move around the plane regularly. In between, carry out leg stretches and foot rotations to help keep blood flowing. Keep well hydrated. And consider wearing compression stockings during the flight. If your legs swell or you become short of breath in the days after a long-haul flight, seek medical attention.
mhouston@irishtimes.com