Anyone traveling by plane for long distances is at an altitude of 9, 000 to 12, 000 meters. A technology that creates a kind of artificial atmosphere has created a pressure in aircraft equivalent to that at an altitude of around 2, 000 to 2, 500 meters, which is about as high as St. Moritz in Switzerland. Research has shown that around half of all passengers suffer from hypoxia - but not everyone notices.
How important is the oxygen?
Research reports by anesthesiologists from Belfast published in the journal "Anesthesia" (Vol. 60, p. 458, 2005) provide disturbing results for air travelers.
54 percent of the passengers had an oxygen content in the blood that was too low, namely 93 percent - the normal oxygen concentration is 97 percent. At first glance, this seems to be just a small difference.
15 liters every hour - oxygen is vital
The chemical formula of oxygen is O 2, because as an unbound gaseous substance it usually consists of a diatomic molecule. On Earth, it occurs more often than any other chemical element, but you can not see, smell, or taste it.
89 percent of the water and 50 percent of the earth's crust consist of oxygen, which the plants produce with the help of leaf greens and light. The breath is composed of about 80 percent nitrogen and 20 percent oxygen in the form of gaseous molecules.
Due to gravity, most air molecules are near the Earth's surface. Towards the top the air gets thinner and thinner, so does the oxygen.
This means: the fewer molecules, the lower the air pressure. On average, we consume about 15 liters of oxygen per hour; On average, humans inhale and exhaust 19, 000 liters of air a day. The breathing activity must be continuous, because oxygen can not be stored like other substances in the body.
Artificially increased pressure in the aircraft
Since only a few people have such a good condition as the mountaineer Reinhold Messner, who can do without oxygen at a height of more than 8, 000 meters, in aircraft the pressure must be artificially increased. The law therefore requires civil airlines to equip their machines with pressurized cabins.
Even breathing 100 percent oxygen would not survive at altitudes above 13, 500 meters.
5 tips that can help against a lack of oxygen
- How fast a passenger has a lack of oxygen depends on his general state of health. For example, smokers have comparatively less oxygen in their blood than non-smokers. Minimizing cigarette consumption one week before a long flight could help provide better oxygenation during the flight.
- If you have a flight in front of you, you should avoid on the days before fast mountain ascents or long diving expeditions to start. After such activities, which severely limit the supply of oxygen, one should take a few days to allow the body to re-accumulate enough oxygen in the blood.
- Athletes, in particular, have fewer problems with oxygen deficiency in the airplane because they automatically have better oxygen saturation in the blood. Running sports outside the week before the flight can help oxygenate the body, but it will not do much if you're never doing any sports.
- Another tip is: sleeping. As we sleep, we consume significantly less energy and oxygen, as our body goes into hibernation. The simplest way to use less oxygen when flying is to sleep as much as possible.
- If the cockpit just allows you, get up and take a few steps! By simultaneously breathing in deeply and slowly, you can additionally improve the oxygen supply. And: Regular leg movement also prevents thrombosis on long-haul flights.
What happens when there is a lack of oxygen?
In the Belfast study, the physicians found that 54 percent of the passengers (84 people between the ages of 1 and 78 years tested) had too little oxygen in their blood.
This O 2 deficiency can explain why many travelers feel uncomfortable or ill after long flights, especially if they had drunk too little, hardly moved and low humidity added.
Compensation of oxygen deficiency
A healthy organism compensates for the lower oxygen content by making the heart beat faster and narrowing the vessels. Heart patients and people with anemia should therefore consult a doctor before flying.
Oxygen deficiency, also called hypoxia, is a disease state that arises at high altitudes. Already in the lowest layer of the atmosphere, the troposphere, the air at 3, 900 meters altitude becomes so thin that oxygen deficiency symptoms can occur.
Symptoms of hypoxia
The physicians Eckhart Schröter and Torsten Hahne describe numerous symptoms, as they have experienced not only traffic pilots, but also paragliders:
- fast and deep breathing (hyperventilation)
- Tingling in the feet, hands and face
- Changes in color vision
- Narrowing the visual field
- Euphoria and drowsiness
Are air travel for pregnant women questionable?
A fetus needs plenty of oxygen for trouble-free development. To find out if this is possible at high altitudes, Professor Renate Huch from the University Hospital Zurich has examined ten pregnant women on 20 flights across Europe.
All clear at start, landing or at full altitude, the heart of the embryo beat as fast as on the ground - a sure sign that it was optimally supplied with oxygen.
Oxygen masks - a bad sign?
Before that, every passenger is afraid: the oxygen masks fall down - a sure sign that something is wrong. What happened?
The aircraft cabins are basically airtight. At high altitudes, where the air pressure is very low outside, the pressure is artificially kept at a normal level. Normal sea level air pressure is about 1, 013 hectopascals.
The air pressure decreases with the altitude and is halved according to a rule of thumb about every 5, 000 meters. If the aircraft is flying at cruising altitude, the machine is inflated, as it were, like a balloon, ie the pressure inside the cabin is higher than the pressure of the environment.
Pressure drop triggers oxygen masks
If the pressure drops, the oxygen masks that are installed above each seat are triggered automatically. Even a leaking valve or a small hole in the plane can let the air escape very slowly and imperceptibly. For this reason, there are several sensors that constantly check the condition inside the cabin.
The oxygen masks are therefore triggered very early. At this time there is no danger for the passengers. The pilots must now bring the aircraft as quickly as possible from the cruising altitude in a descent to a height that allow trouble-free breathing even without oxygen masks. At least from an altitude of less than 4, 000 meters, you no longer have to wear oxygen masks.