That first sip of a drink while flying a couple miles above the Earth’s surface is intoxicating. By the time you finish the beverage (which should, by the way, be a Bloody Mary), you feel a heavy buzz—much more than you feel when you drink the same amount at sea level. But do you actually get more drunk on an airplane and at high altitudes? No, but you might feel like you are.
“Your blood isn’t oxygenated as much at altitude as it is on the ground,” Dr. David Greuner, a cardiovascular and thoracic surgeon, told Thrillist. “So, there’s just not as much oxygen going to the brain, and you get hypoxic. It’s the same reason you might feel light-headed at high altitudes or when you exercise too hard. You’re light-headed, and you might think it means you’re more drunk.”
Commercial planes typically fly between 30,000 and 40,000 feet. The cabin is pressurized to the equivalent of the air at around 6,000 to 8,000 feet to make it manageable, according to the World Health Organization. That’s still high enough for some people to feel an impact, though. Higher altitude means lower air pressure, and the lower the air pressure, the less oxygen a person’s blood is able to take in. When there’s an oxygen deficiency in the body, it’s called hypoxia. According to Higher Peak, an altitude training device company, the effective oxygen percent decreases dramatically from sea level to flying level. Effective oxygen is 20.9 percent at 0 feet, 16.6 percent at 6,000 feet and 15.4 percent at 8,000 feet.