Physiological Challenges On The Airplane

A variety of challenges revolves around traveling.  Among all challenges, the physiological challenges on the airplane are unique and in most cases unavoidable.  They directly affect our well-being during and after the flight, a.k.a. how good we feel, in conjunction with psychological, emotional, social, and other challenges we may face when traveling.  Let's find out about what really happens to the body during the flight.

Fact 1: Air pressure on a commercial airliner cabin is 75% of that at sea level.

Airplane cabins have to be pressurized because the air at the altitude airplanes fly is too thin for humans to breathe.  The average passenger jet has a cruising altitude of between 30,000 feet to 40,000 feet, and long flights are typically assigned to cruise at the higher side of this range.  While a private jet can fly at a height of up to 45,000 feet, most cruise at 41,000 feet which is generally higher than a commercial airline flight.  

Atmospheric pressure is created by the weight of the air.  As we ascend to higher altitude, atmospheric pressure goes down.  This means that air gets thinner as we ascend higher. Since the body gets oxygenated most effectively and efficiently with the density of air at sea level, altitude sickness may happen due to the deficiency of oxygen (hypoxia) at higher altitudes.

The regulations specify that air pressure in the cabin of a commercial airliner must not be lower than that found at an altitude of 8,000 feet (2,438m), which is 75% of air pressure at the sea level.  This altitude was chosen to maintain the integrity of the shape of the aircraft by keeping the difference between internal and external atmospheric pressures of the aircraft as small as possible; while, at the same time, making sure that the atmospheric pressure inside the air cabin is not too low, as passengers could suffer from altitude sickness due to oxygen deprivation.

Altitude sickness is commonly experienced by the people who are not acclimatized to high altitudes and who moved from low altitudes to high altitudes above 8,000 feet quickly.  Signs and symptoms of altitude sickness are similar to a hangover, including throbbing headache, loss of appetite, nausea, sickness in stomach, fatigue, trouble sleeping, and dizziness.  If you've ever been to Aspen, Colorado (7,907 feet high above sea level), Vail, Colorado (8,022 feet high) or Mexico City (7,382 feet high), you may have experienced becoming fatigued more easily than at sea level.

Minor symptoms such as breathlessness may occur at an altitude of 5,000 feet, and altitude sickness can begin to appear around 6,600 feet above the sea level. No wonder why we sometimes experience mild altitude sickness-like symptoms on a flight, as the air pressure is set as if we are at an altitude of 8,000 feet.  

The cabin pressure more evidently affects people sensitive to pressure changes in their inner ears and sinuses.  Scuba divers flying within the "no fly" period after a dive are at risk of decompression sickness, as dissolved gasses, mainly nitrogen, can come out of solution and create bubbles in the bloodstream.  During ascending to and descending from cruising altitude, passengers may experience pain in middle ear, and/or tooth pain due to the change in pressure.   

Some business jets keep the cabin pressure equal to that at 6,000 feet despite the fact they fly at higher altitudes than commercial airlines.  The cabin pressure equal to the lower altitude and closer to sea level creates an atmospheric environment where passengers can oxygenate their blood better and enjoy a more comfortable flight with less physiological challenges related to altitude sickness than they may encounter in a commercial flight.  

When we are about to fly, especially on a commercial airliner, hypoxia, or oxygen deficiency during flight is one of the things I suggest that we all should consider.  I would like to introduce easy self care tips in the next posting.  



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