Drunk and High in Denver

Does alcohol have more of an effect when you’re up in the mountains?

With Democrats finishing up their convention in Denver, reports suggest that the parties in the Mile High City haven’t been quite as wild as in past campaigns. One culprit may be concerns about the altitude, which caused the DNC to warn delegates that “alcoholic drinks pack more of a wallop here than at sea level.” So does altitude really make you drunker?

Probably not, but alcohol could make your altitude sickness a little worse. In the 1930s, R.A. McFarland, a Columbia University psychologist, began studying the interaction of altitude and alcohol to figure out what effects drinking might have on pilots. After years of research, he eventually concluded that “the alcohol in two or three cocktails would have the physiological action of four or five drinks at altitudes of approximately 10,000 to 12,000 ft.” That conclusion has been accepted by many as an article of faith ever since. But the limited research into the topic doesn’t back it up.

To start with, altitude doesn’t seem to change how the body metabolizes alcohol. A study conducted in Austria tested the impact of drinking on young male alpinists near sea level and at an altitude of almost 10,000 feet. The participants’ blood-alcohol content after drinking the equivalent of 1 liter of beer was nearly identical regardless of their location. Another study (PDF) conducted by the FAA in the late 1970s found that while both alcohol and altitude independently impacted the performance of pilots in joystick-control tests, there was “no significant interaction” between the two. (A similar experiment found that the impact of alcohol on subjects answering math problems was the same at sea level and 12,000 feet.)

On the other hand, it is possible that alcohol exacerbates some of the problems associated with acclimating to high altitudes. (The main symptoms of altitude sickness—headache, dizziness, a suppressed appetite—resemble those of a hangover.) That same Austrian study found that the participants who drank the alcoholic beverage had slightly impaired breathing up in the mountains compared with subjects whose drinks didn’t have any alcohol. Since you need to breathe more to compensate for low oxygen at high altitudes, drinking could make you more likely to experience hypoxia. Still, the effects of moderate drinking on altitude sickness are probably rather modest. Indeed, a study of several thousand visitors to Rocky Mountain resorts found that adults who drank within the first 24 hours of arriving actually had lower rates of acute mountain sickness—although the results may have been skewed by visitors who decided not to drink because they already felt ill.

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Explainer thanks Peter Hackett of the Institute of Altitude Medicine and David Shlim.