Thin air – lack of oxygen in the plane?
If you travel long distances by plane, you will be at an altitude of 9,000 to 12,000 meters. Thanks to a technology that creates a kind of artificial atmosphere, the pressure in aircraft corresponds to that at an altitude of around 2,000 meters to 2,500 meters, i.e. about as high as St. Moritz in Switzerland. Studies have shown that around half of all passengers suffer from a lack of oxygen – but not everyone notices it.
How important is the oxygen?
Research by Belfast anesthesiologists, published in the journal Anesthesia (Vol. 60, p. 458, 2005), provides worrying results for air travelers.
54 percent of the passengers had a blood oxygen level that was too low, namely 93 percent – the normal oxygen concentration is 97 percent. At first glance, this seems to be only a small difference.
15 liters per hour – oxygen is vital
The chemical formula of oxygen is O 2 because, as a free gaseous substance, it normally consists of a diatomic molecule. It’s more common on Earth than any other chemical element, but you can’t see, smell , or taste it .
89 percent of water and 50 percent of the earth’s crust consists of oxygen, which plants produce with the help of leafy greens and light. The air we breathe is made up of about 80 percent nitrogen and 20 percent oxygen in the form of gaseous molecules.
Because of gravity, most air molecules are close to the surface of the earth. As you go up, the air gets thinner and thinner, and so does the oxygen.
This means: The fewer molecules, the lower the air pressure. On average, we use about 15 liters of oxygen per hour; on average, a person breathes in and out 19,000 liters of air every day . Breathing activity must be continuous because oxygen cannot be stored in the body like other substances.
Artificially increased pressure in the aircraft
Since only a few people are in such good condition as the mountaineer Reinhold Messner, who can survive at an altitude of well over 8,000 meters without oxygen, the pressure in airplanes has to be artificially increased. The law therefore stipulates that civil airlines must equip their machines with pressurized cabins.
Even if you were breathing 100 percent oxygen, you couldn’t survive at altitudes above 13,500 meters.
5 tips that can help against a lack of oxygen
- How quickly a passenger becomes oxygen deficient depends on their general health. Smokers have comparatively less oxygen in their blood than non-smokers. Minimizing cigarette smoking a week before a long flight may help you stay oxygenated during the flight.
- If you have a flight ahead of you, you should avoid starting fast mountain climbs or long diving expeditions in the days before. After such activities, which severely limit the supply of oxygen, you should allow yourself a few days to allow the body to accumulate enough oxygen in the blood again.
- Athletes in particular have fewer problems with lack of oxygen on the plane because they automatically have better oxygen saturation in their blood. So, exercising outside the week before your flight can help oxygenate your body, but won’t do much if you never exercise.
- Another tip is: sleep. While we are sleeping, we use significantly less energy and oxygen as our body is put into a resting state. So the easiest way to use less oxygen while flying is to sleep as much as possible.
- If the cockpit allows, get up and take a few steps! You can also improve the oxygen supply by breathing deeply and slowly at the same time. And: regular movement of the legs also prevents thrombosis on long-haul flights.
What happens when there is a lack of oxygen?
In the Belfast study, the doctors came to the conclusion that 54 percent of the passengers (84 people between the ages of 1 and 78 were tested) had too little oxygen in their blood.
This lack of O 2 could explain why many travelers feel unwell or sick after long flights, especially if they have drunk too little, hardly moved and the humidity is low.
Compensation for lack of oxygen
A healthy organism compensates for the lower oxygen content by making the heart beat faster and the blood vessels constrict. Heart patients and people with anemia should therefore definitely consult a doctor before flying.
Oxygen starvation, also called hypoxia , is a medical condition that arises at high altitudes. Even in the lowest layer of the atmosphere, the troposphere, the air at an altitude of 3,900 meters is so thin that symptoms of oxygen deficiency can occur.
Symptoms of lack of oxygen
The physicians Eckhart Schröter and Torsten Hahne describe numerous symptoms that not only traffic pilots but also paraglider pilots have experienced:
- rapid and deep breathing ( hyperventilation )
- Tingling in the feet, hands and face
- dizziness
- changes in color vision
- narrowing of the field of vision
- euphoria and drowsiness
Is air travel dangerous for pregnant women?
A fetus needs plenty of oxygen for proper development. In order to find out whether this is the case at high altitudes, Professor Renate Huch from the University Hospital in Zurich examined ten pregnant women on 20 flights across Europe.
The all-clear is clear here: during take-off, landing or at full altitude, the embryo’s heart beat just as fast as on the ground – a sure sign that it was optimally supplied with oxygen.
Oxygen masks – a bad sign?
Every passenger is probably afraid of that: the oxygen masks fall off – a sure sign that something is wrong. What happened?
The aircraft cabins are basically airtight. At high altitudes, where the outside air pressure is very low, the pressure is artificially maintained at normal levels. Normal air pressure at sea level is about 1,013 hectopascals.
Air pressure decreases with altitude and, as a rule of thumb, halves every 5,000 meters. When the aircraft flies at cruising altitude, the machine is inflated like a balloon, so to speak, which means that the pressure inside the cabin is higher than the pressure in the environment.
Pressure drop triggers oxygen masks
If the pressure drops, the oxygen masks installed above each seat are automatically triggered. Even a leaky valve or a small hole in the aircraft can allow the air to 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 point there is no danger for the passengers. The pilots now have to descend as quickly as possible from the cruising altitude to an altitude that allows for easy breathing even without oxygen masks. At the latest from an altitude below 4,000 meters you no longer have to wear oxygen masks.