A new study reveals the dangers of drinking alcohol on board on heart health, and scientists call for restrictions on flights Science and health

The combination of alcohol and plane cabin pressure can threaten passengers' heart health, especially on long-haul flights, suggests a first-of-its-kind study, published in the scientific journal Thorax. The duo reduces the amount of oxygen in the blood (SpO2) and increases the heart rate for a long time. This effect occurs even in young and healthy people.

The more alcohol is consumed, the greater these effects, especially among older passengers and people with pre-existing medical conditions. The researchers suggest that now may be a good time to consider restricting access to alcohol on long-haul flights.

The researchers explained that atmospheric pressure decreases significantly with altitude, causing the blood oxygen saturation level to drop to about 90% (73 hPa) in healthy passengers at high altitudes. A further drop in blood oxygen saturation below this limit is defined as hypobaric hypoxia – or low blood oxygen at higher altitudes.

Alcohol relaxes the walls of blood vessels, which increases the heart rate during sleep, an effect similar to hypoxia under stress. The researchers wanted to know if the combination of alcohol plus cabin pressure at flight altitude could have an additional effect on sleeping passengers.

In the study, they randomly divided 48 people between the ages of 18 and 40 into two groups stratified by age, gender, and BMI. Half of them were allocated to the sleep laboratory under conditions of normal atmospheric pressure (sea level) and the other half to the altitude chamber that simulates cabin pressure at cruising altitude (2,438 meters above sea level).

Twelve people in each group slept for 4 hours without drinking alcohol, while 12 people slept for 4 hours while drinking alcohol for one night, followed by two recovery nights and then another night where the process was reversed.

Participants drank the equivalent of two cans of beer (5%) or two glasses of wine (175 ml, 12%) straight up with vodka at 11:15 p.m., and their sleep cycle, oxygen saturation, and heart rate were monitored continuously until 4 p.m. . The final analysis included results from 23 subjects in the sleep laboratory and 17 subjects in the elevation chamber.

The results showed that the combination of alcohol and simulated cabin pressure at aircraft altitude caused oxygen saturation to drop to an average of just over 85% and a compensatory increase in heart rate to an average of approximately 88 beats/minute during sleep.

This compares to just over 88% oxygen saturation and just under 73 beats per minute among those sleeping in the elevation chamber and not drinking alcohol.

Among those who drank alcohol in the sleep lab, the equivalent numbers were just under 95% for oxygen saturation, just under 77 bpm and heart rate, and just under 96% and just under 64 bpm for those who did not drink.

Oxygen levels below healthy clinical standards (90%) were sustained for 201 minutes with a combination of alcohol plus simulated cabin pressure at cruising altitude. This compares to a period of 173 minutes without alcohol and 0 minutes with or without alcohol in sleep laboratory conditions.

The deepest sleep (stage N3 of the sleep cycle) was reduced to 46.5 minutes under combined exposure to alcohol and airplane cabin pressure, compared to both laboratory sleep conditions: after alcohol, 84 minutes; Without alcohol 67.5 minutes.

REM sleep was also shorter among those exposed to hypoxia and alcohol. Both deep sleep and REM sleep are important stages of sleep recovery.

Limitations of the study include the fact that the sample was small and that the participants were young and healthy, so they do not reflect the general population. In addition, participants slept in the reclining position, a luxury typically only available to those traveling first or business class, so the results may not apply equally to most airline passengers flying economy class.

“Taken together, these findings suggest that even in healthy young people, the combination of alcohol intake and sleep under hypobaric conditions places significant stress on the cardiac system and may exacerbate symptoms in patients with heart or lung disease, for example.” Authors.

The researchers note that these effects may be greater in older people, adding: “Cardiovascular symptoms are prevalent in 7% of in-flight medical emergencies, with cardiac arrest accounting for 58% of aircraft diversions.”

“Professionals, passengers and cabin crew should be informed of the potential risks, and it may be worth considering changing regulations to restrict access to alcoholic beverages on board,” they stress.