Drinks on a plane: Consider saying no
Cocktails at cruising altitude are tied to potentially serious health risks.
- Reviewed by Anthony L. Komaroff, MD, Editor in Chief, Harvard Health Letter; Editorial Advisory Board Member, Harvard Health Publishing
Some people enjoy having a bit of bubbly when jetting off to a new locale, perhaps as a way to toast the start of an adventure. But drinking champagne or any other alcoholic beverage on an airplane might pose risks ranging from falls to heart attacks. This is particularly true if you intend to sleep on the flight, such as on a long-haul overnight flight. So it might be time to rethink your drink order.
Your body on a plane
Before you even take a sip of alcohol, your body experiences physiological effects of being high above sea level: there's less atmospheric pressure to force oxygen into red blood cells for delivery throughout your body, and blood oxygen drops from normal levels of 96%–100% to about 90%, or even below 90%.
Your body has a way to compensate for that. You breathe faster to take in more oxygen. Your heart rate increases to move blood through your system faster. However, reduced blood oxygen levels and increased heart rates can be dangerous for people with a heart condition.
Complicating factors
Small dips in blood oxygen can become more pronounced on a plane when you add other factors into the mix, and drinking alcohol is one of them. "Some studies suggest that alcohol impairs the ability of red blood cells to take up oxygen by altering hemoglobin, the molecule that actually carries the oxygen," says Dr. Matthew Mosquera, medical director of the Alcohol, Drugs, and Addiction Inpatient Program at Harvard-affiliated McLean Hospital.
The following factors can also lead to lower blood oxygen:
Aging: Our ability to adapt to changes in blood oxygen levels declines as we age.
Sleeping: Breathing normally slows during sleep, even on an airplane.
Underlying conditions: Less oxygen gets to your lungs if you have lung disease, sleep apnea (pauses in breathing during sleep), or heart problems.
What's the risk?
The more contributors to low blood oxygen you have, the harder it becomes for your body to compensate, especially on a plane. That was illustrated in a study published online June 3, 2024, by Thorax.
Researchers wanted to know more about the combined effects of alcohol consumption and airplane cabin pressure during sleep on a plane. They randomly assigned 48 healthy people (ages 18 to 40) to spend two nights sleeping at normal air pressure or at the equivalent of airplane cabin pressure. Participants drank alcohol (the equivalent of two beers or two glasses of wine) before one of the nights and were sober for the other. They also wore devices measuring their blood oxygen and heart rate.
Compared to sleeping in normal air pressure, sleeping in airplane cabin pressure made blood oxygen levels lower and heart rates higher. Combining drinking and sleeping when in airplane cabin pressure made oxygen levels even lower and heart rate even higher.
"Drinking and sleeping on a plane puts a big strain on your body, especially your cardiovascular system," Dr. Mosquera says. "And there's even more strain if you have heart or lung disease. It places you at a higher risk for a heart attack or stroke."
Other alcohol risks on a plane
Drinking alcohol on a plane poses additional health risks. For example, it
- increases your fall risk
- causes dehydration, which adds to the strain on your cardiovascular system
- impairs your judgment and ability to focus (which you don't want when it's time to get off the plane)
- may help you fall asleep, but reduces the time you spend in good-quality deep sleep.
What you should do
Is it best to pass on alcohol when the drink cart approaches? That depends. "If you're healthy, drinking in moderation might be okay," Dr. Mosquera says. However, he urges you to consider the following:
- Think twice about drinking alcohol and taking certain medications. Alcohol can worsen drowsiness from drugs that make you sleepy.
- Drink extra water. This will help your body flush out the alcohol, and prevent dehydration caused by alcohol.
- Be mindful of your balance. Take your time going from a sitting position to standing, to avoid falls.
And if you have heart or lung disease, sleep apnea, or chronic lung disease, or if you've had a stroke in the past - especially if you plan to sleep on the flight - it may be wisest not to drink alcohol.
Image: © Halfdark/Getty Images
About the Author
Heidi Godman, Managing Director
About the Reviewer
Anthony L. Komaroff, MD, Editor in Chief, Harvard Health Letter; Editorial Advisory Board Member, Harvard Health Publishing
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