Q: Is it safe to mix alcohol and caffeine?—Juliet, Anchorage, Ala.
A: Our last Health Q&A covered the effects of coffee, tea and other caffeinated drinks on hangover, the unpleasant result of drinking too much alcohol in too short a time. Contrary to popular belief, caffeine almost certainly won’t help your hangover, and it may even make you feel worse. But what about the basic safety of mixing caffeine and alcohol?
Experts say the main risk of combining caffeine and alcohol is … drinking too much alcohol. While enjoying coffee liqueur or an Irish coffee in moderation is unlikely to cause problems, caffeine masks the normal effects of alcohol, especially drowsiness, and makes you feel less intoxicated than you are. That, in turn, could lead you to consume more alcohol than you intend to drink.
Caffeine and Alcohol: Proceed with Caution
Dr. Mary Claire O’Brien, professor of emergency medicine at Wake Forest University School of Medicine, told Wine Spectator that consuming caffeine and alcohol together can be risky. “Ingested caffeine temporarily ‘blocks’ the sleepiness that is typically associated with significant alcohol consumption. An individual who relies on ‘feeling sleepy’ to know when they have ‘had enough’ can be fooled and may keep drinking well beyond the point that is safe.”
The bottom line? “Individuals who combine caffeine and alcohol may underestimate their level of impairment.” Consuming the two substances together can make you prone not just to hangover the next day, but to dangerous levels of overconsumption.
The Centers for Disease Control and Prevention also notes that “caffeine has no effect on the metabolism of alcohol by the liver.” That means a cup of coffee isn’t going to help you ‘sober up’ if you’ve had too much to drink. Only time can do that.
What Happens When You Mix Caffeine and Alcohol?
Dr. Sergi Ferré, chief of the integrative neurobiology section of the intramural research program at the National Institute on Drug Abuse, told Wine Spectator that the combination of caffeine and alcohol can be risky because the substances have different effects on a chemical called adenosine. “Your body naturally produces … adenosine, which builds up throughout the day and causes you to feel sleepy. But caffeine blocks adenosine from working on brain cells, which prevents you from feeling sleepy.”
Alcohol, on the other hand, “increases adenosine in the blood and the brain. Adenosine is mostly responsible for the drowsiness associated with alcohol consumption.”
The end result is that “when consumed together, caffeine amplifies the rewarding effects of alcohol and prevents the drowsiness that is typically caused from consuming alcohol. Therefore, caffeine facilitates alcohol consumption by increasing its wanted effects and by masking its non-wanted intoxication effects.”
Dr. Ferré adds that “consuming caffeine and alcohol together may cause people to drink more alcohol, which has been associated with more prolonged hangovers and more pronounced alcohol poisoning, including death. The association between caffeine and alcohol has also been shown to increase the engagement in risky behaviors, such as drunk driving, as well as alcohol-related violence.” That association has been particularly strong in studies of people consuming alcohol together with energy drinks.
How Does Mixing Caffeine and Alcohol Affect Your Heart?
Caffeine and alcohol both tend to cause a temporary increase in heart rate and blood pressure, which has led some researchers to speculate that combining the substances could pose a risk to heart health—particularly in people prone to irregular heartbeat. However, research into the combination’s effects on the heart is limited. Moderation remains the best counsel.
As always, talk to your healthcare provider about incorporating alcohol into a healthy lifestyle.—Kenny Martin
