Don't drink alcohol on an airplane, experts warn. But if you must, follow this advice.

Getting drunk on a plane is one of those bucket list items that sound fun in theory — especially if it prefaces a much-needed vacation — but in reality, you’re much better off saving the beers for the beach. (Though even that can be risky.) Drinking, in general, is not good for you, but doing so at 30,000 feet elevation in particular has different health implications from drinking on land. So we asked experts to explain what happens to your body when you drink alcohol on a plane and why you might want to think twice before flagging down a flight attendant for a round or two of those mini liquor bottles.

You actually get drunk faster

The higher the altitudes you reach on a plane, the lower the oxygen levels and atmospheric pressure, Dr. Thomas Pontinen, physician and co-founder of MAPS Centers for Pain Control, tells Yahoo Life. In normal altitudes, oxygen binds with hemoglobin to transport oxygen throughout the body and keep vital processes running, including the body’s ability to flush alcohol, he explains. “The lower our oxygen levels, the harder it is to metabolize and eliminate alcohol,” he says.

Drinking alcohol also exacerbates those already compromised oxygen levels “because it prevents some oxygen from attaching to hemoglobin,” Pontinen says. This can lead to dizziness, headache and even confusion. Obviously, these risks are not ideal for anyone to take; however, Dr. Leonard Pianko points out that people over 65 and those with medical conditions should be particularly aware of them.

Alcohol can also hit you harder if you don’t eat pre-takeoff or if you only snack on filler foods with little nutritional value, like those free pretzels flight attendants hand out. Whether you’re in the air or on land, “an empty stomach makes you get drunk faster,” notes Pontinen. “If there is no food to digest anymore, then the stomach has no choice but to open its valves and let alcohol enter the intestines, where major absorption occurs.” To counteract those effects, he recommends filling up on slower-digesting foods that contain healthy fats (think: nuts, hard-boiled eggs or yogurt).

You’re more likely to dehydrate

The air inside planes has low humidity levels — about 10%-20% humidity compared to the 35%-65% humidity you’d find in more typical environments — and that dry cabin air can lead to dehydration, which can cause classic symptoms such as dizziness, headache and fatigue, Dr. Elizabeth Sharp tells Yahoo Life. Add that to the fact that you may also drink less water than usual on a plane while you’re busy binge-watching movies or snoozing. Consuming alcohol on top of that can heighten dehydration risk. Pontinen adds that alcohol is also a diuretic, which can intensify dehydration.

There’s an increased blood clot risk

Alcohol can lead to dehydration, which, when combined with prolonged sitting during flights, increases the risk of developing blood clots, also known as deep vein thrombosis. “It’s not just the alcohol,” Pianko notes. “It’s the effect of alcohol combined with what you eat, what medications you take, digestion and sleep. What I worry about most is that individuals who drink alcohol take a sleeping pill and cross their legs, which can lead to increased blood clotting.”

Drinking then sleeping on planes may be harmful to your heart

In general, alcohol increases the risk of heart disease because it weakens your heart muscles and raises your blood pressure, Pontinen explains. A June 2024 study explored that further by examining the combined effects of cabin pressure and drinking alcohol and then sleeping on long flights in both healthy people and those with preexisting heart conditions. Findings showed that even healthy participants experienced cardiac strain in the form of lowered blood oxygen levels and an increased heart rate. This not only caused hypoxia — or low blood oxygen levels found at higher altitudes — but also disrupted deep sleep in participants.

These effects pose a particular risk to those who already have heart issues. Based on their findings, the researchers recommend that people with obstructive sleep apnea or obesity hypoventilation syndrome, which is a breathing disorder, avoid alcohol for 12 hours prior to flying. But in general, the researchers say it may be beneficial to restrict access to alcoholic beverages on flights in light of the potential heart health risks.

While it’s best to avoid alcohol entirely during a flight, if you still want to imbibe, Sharp recommends drinking a glass of water for every alcoholic beverage consumed in-air. And of course, drink in moderation, which Sharp says is no more than two drinks — even on those long-haul flights.