The Science of Flight and the Human Body

By Charles Li MD

January 04, 2019

  • It's not just you, a lot of people feel tired after a flight.

  • Your body undergoes some dramatic changes once in the air.

  • Some recent studies have characterized the science behind changes, and offer clues for why you feel so different on and after a flight.

Effect of cabin air pressure during a flight

The most obvious change is the dramatic drop in air pressure as you take off.

A Boeing 737 flies at up to 41,000 feet, at is significantly higher than Mount Everest. At these heights, we would not be able to breathe.

Fortunately, thanks to Cabin Pressurization, the air in a plane is pressurized to a much more comfortable space 6000-8000 ft.

However, even this can be somewhat uncomfortable.

This is equivalent to moving instantly from San Francisco to Denver, or to hiking to the peak of Grand Teton in an hour.

On a physiological level, the reduction in air pressure causes the air in your body cavities to literally expand as you take off.

This is why your ear pops, why some people have belly pain, and why your cold symptoms get worse.

Effect of Reduced Oxygen in the Bloodstream

Chart of Oxygen on an airplane in flight and its effects

If you ever feel tired or have experienced muscle discomfort on a flight, a study shows that a minor lack of oxygen may be the culprit.

Because of the air pressure drop, you’re cells literally receive less oxygen from your blood. In a study published in the NEJM, patients who were monitored in a simulated flight environment experienced a nearly 5% drop in their blood oxygen.

When napping, the subjects' blood oxygen appeared to drop even further. The study found that that this, combined with changes in air pressure, was associated with fatigue and muscle discomfort.

Fortunately, your blood oxygen quickly recovers during landing, and the minor drop is completely harmless, albeit mildly uncomfortable, for the vast majority of passengers.

Long Flights and Blood Clots

data for the prevalence and prevention of DVT (deep vein thromboses) in flight

One health issue that has attracted some publicity is the risk of blood clots during long flights. When you are sitting for up to 12 hours straight on a flight, your blood can spontaneously form clots, that can then travel to your lungs and get stuck.

In one study, 5% of high risk patients were found to have blood clots over a 12 hour flight.

Fortunately, most of these small clots are not harmful. However, on occasion, these can lead to more serious issues.

For patients who have known clotting issues or at high risk of clots, one possible prevention method are DVT stockings, which have been shown to significantly reduce the incidence of blood clots.

Explore More
thumbnail for microbiome-kids-development
thumbnail for music-therapy-depression
thumbnail for heart-attack-mortality-data
thumbnail for reading-math-intelligence
thumbnail for diet-drinks-vs-regular-soda
thumbnail for school-breakfast-obesity
thumbnail for mushrooms-dementia
thumbnail for workout-over-40
thumbnail for genetics-morning-people
thumbnail for physician-burnout-effects
thumbnail for walking-thinking
thumbnail for caffeine-calories
thumbnail for autism-mmr-stats
thumbnail for hivcure
thumbnail for heart-rhythm-monitor
thumbnail for words-predict-depression
thumbnail for butter-olive-oil-coconut-oil
thumbnail for pushups-heart-health
thumbnail for fluorosis-kids-teeth
thumbnail for brownfat
thumbnail for tolerancestudy
thumbnail for ketaminefda
thumbnail for systemicsclerosis
thumbnail for parentagreement
thumbnail for dietexercisecognition
thumbnail for maternityhospitals
thumbnail for catbiteguide
thumbnail for ultraprocessedfoods
thumbnail for bmigfr
thumbnail for nightsweats
thumbnail for hiv2030
thumbnail for vapeyouth
thumbnail for opioidprojections
thumbnail for cavitykids
thumbnail for ptsdstats
thumbnail for penicillinallergies
thumbnail for frostbiteaid
thumbnail for lipoproteina
thumbnail for opioidpayments
thumbnail for carbenergy
thumbnail for socialanxietysigns
thumbnail for sadsymptoms
thumbnail for healthequality
thumbnail for eggcellent
thumbnail for top_5_anxiety_disorders
thumbnail for kidactivity
thumbnail for flu2019
thumbnail for writingtyping
thumbnail for sahealth
thumbnail for depressionmi
thumbnail for brcaova
thumbnail for flightscience
thumbnail for travelerdia