Alcohol consumption on an airplane. What do scientists say?

The combination of alcohol and the pressure that prevails in the cabin of an airplane at cruising altitude is proving to be particularly detrimental to health, as it puts a significant strain on the cardiovascular system. These are the findings of a new scientific study published June 3, 2024 in the journal Thorax, published by the British Thoracic Society. The study's authors warn that alcohol drunk in the skies could prove to be an explosive mix for some passengers.

To prove this thesis, the researchers engaged 48 adults between the ages of 18 and 40, whom they divided into two groups based on their age, gender and weight, or more precisely, their BMI. Half of the subjects were placed in a sleep study laboratory, under atmospheric conditions at sea level, while the other half were invited to an altitude chamber mimicking the pressure in an airplane cabin at a cruising altitude of 2438 meters above sea level. In each group of 24 subjects, 12 slept 4 hours without alcohol, and 12 slept 4 hours after drinking the equivalent of 2 cans of beer (5%) or 2 glasses of wine (175 ml, 12%) or a glass of pure vodka. The goal was to measure sleep cycle, blood oxygen saturation and heart rate.

Experts also wanted to see if the combination of alcohol, high atmospheric pressure prevailing at cruising altitude affects the health of sleeping passengers.

The study recalled that atmospheric pressure decreases exponentially with altitude, resulting in a drop in blood oxygen saturation from 95% to 90% in healthy passengers. This condition does not endanger a person and the body compensates for the deficiency on its own. However, under these conditions, due to the lack of oxygen resulting from altitude, alcohol accelerates the heart rate during sleep. During the study, it was found that the combination of alcohol, pressure and altitude caused a drop in oxygen saturation to 85% and a compensatory increase in heart rate to 88 beats per minute during sleep. Those subjected to the same conditions but not drinking alcohol had saturations of 88% and heart rates below 73 beats per minute during sleep.

In the group of people tested in a laboratory located at sea level, alcohol did not have the same consequences as when flying in an airplane. In the "drinking group," oxygen saturation was 95% and the number of heart beats per minute was 77. In the group without alcohol, saturation was at 96% and the heart beat 64 times per minute. The study also found that the sleep of drinkers was worse than that of those who remained sober. It was characterized by shortened deep sleep time and shorter paradoxical sleep, and consequently worse recovery.

The results of the study found that even in young, healthy people, the combination of alcohol consumption and sleeping in hypobaric conditions places a significant strain on the cardiac system and can lead to exacerbation of symptoms in patients with heart or lung disease. The researchers stress that these effects may be even more significant in older people, while reminding that cardiovascular symptoms account for 7% of in-flight medical emergencies, and that cardiac arrest is the cause of 58% of aircraft diversions. In light of these studies, the conclusion can be taken that limiting access to alcohol on board aircraft would result in a reduction in cardiovascular incidents, sometimes with tragic consequences. The minimum recommended action is to inform passengers and crew about the possible consequences of consuming alcoholic beverages on board aircraft.