Drinking during a flight reduces blood oxygen: study

Drinking alcohol during a flight, combined with cabin pressure, might pose a risk to the heart health of sleeping passengers, especially on long journeys, as well as affecting sleep quality, a laboratory study suggests.

The research published in Thorax, a British Medical Journal group, and conducted by German researchers, indicates that this combination reduces oxygen in the blood and increases heart rate, even in young and healthy people, EFE points out.

The higher the alcohol consumption, the greater these effects may be, especially among older passengers and those with pre-existing medical conditions, the researchers said.

The study was conducted in a laboratory, in an altitude chamber, which resembles the environment in the pressurized cabin of an airplane, and in a sleep laboratory.

A simulated environment “differs significantly from a normal trip, where expectations and conditions vary,” according to researcher Esteban Ortiz of the University of the Americas (Ecuador), who did not participate in the test and is quoted by Science Media Centre, a scientific resource platform for journalists.

For the study, two groups of 18- to 40-year-olds were assigned. Half were assigned to a sleep laboratory under normal ambient atmospheric pressure (sea level) and the other to an altitude chamber that mimicked cabin pressure at cruising altitude (2,438 meters above sea level). Twelve people in each group slept for four hours without drinking alcohol and for the same number of hours with alcohol for one night, followed by two recovery nights and one night in which the process was reversed.

Participants drank an amount of pure vodka equivalent to two cans of beer or two glasses of vodka. Sleep cycle, saturation and heart rate were monitored continuously over the four hours.

The final analysis included results from 23 people in the sleep laboratory and 17 in the altitude chamber.

The combination of alcohol and simulated cabin pressure caused blood oxygen saturation to drop to an average of just over 85% (for most people the normal level is 95% or higher) and a compensatory increase in heart rate to an average of almost 88 beats per minute during sleep.

For those who slept in the altitude chamber but did not drink alcohol, the average saturation was 88% and just under 73 beats. Those who remained in the sleep laboratory recorded 95% saturation and just under 64 beats among those who had not drunk alcohol.

As for sleep, the deepest type of sleep was reduced to 46.5 minutes under the combined exposure to alcohol and simulated cabin pressure. In the sleep laboratory, this phase lasted 84 minutes for those who had drunk and 67.5 minutes for those who had not.

The researchers acknowledge the small sample size and that the participants were young and healthy, so they do not reflect the general population. In addition, the sleep was done in a supine position, a position not possible for those traveling in economy class.

In any case, they considered that, “taken together, these results indicate that, even in young and healthy individuals, the combination of alcohol intake and sleeping under hypobaric conditions places a considerable burden on the cardiac system and might cause an exacerbation of symptoms in patients with heart or lung disease.”

In his commentary on the study, Ortiz noted that the alcohol was consumed in the form of a shot, which can be consumed more abruptly than a glass of wine or a beer during a flight, which is generally longer, and that he excluded the factor of food, which can significantly influence the results.