Why your alcohol tolerance diminishes as you age

By Stacey Colino

If you’ve noticed that having a cocktail or two packs a bigger punch now than it did when you were younger, it’s not your imagination.

Many people don’t realize that both men and women develop an increased sensitivity and a decreased tolerance to alcohol as they get older. It’s important to pay attention to this issue because research has shown that alcohol use has been increasing among people ages 65 and older in recent years—and the size of the older adult population is expanding rapidly now that people are living longer, notes George Koob, a neuroscientist and director of the National Institute on Alcohol Abuse and Alcoholism. “People are largely unaware of the physiological changes [related to aging] that lead to higher blood alcohol levels and bigger impairments in behavior and cognition.”

“The effects may be sneaky in the sense that people think, Well, I used to be able to drink X—but they can’t necessarily pick up where they left off because it’s going to have more of an impact when they’re older,” says Michael Weaver, medical director of the Center for Neurobehavioral Research on Addiction at the University of Texas Health Science Center at Houston. “There are a lot of physiological changes that take place as we get older.”

The simple truth: having one martini or margarita in your 60s or 70s could affect you the way two or three of these cocktails did in your 20s or 30s.

What’s behind the lower tolerance
As people get older, their bodies change. Over decades, for example, a person’s body composition shifts: The percentage of body fat tends to increase as people get older, even if their body weight stays the same, and the amount of water in the body decreases.

A study in a 2023 issue of the journal Kidney Research and Clinical Practice found that in people whose body weight is in the normal range, water accounts for 62 percent of that weight between the ages of three and 10; after that, it stays steady in males and declines to 55 percent in females between the ages of 11 and 60. At age 61, body water decreases in both sexes—to 57 percent in men and 50 percent in women.

The decline in the body’s water content is significant because “alcohol is a water-soluble substance,” says Alison Moore, director of the Stein Institute for Research on Aging and the UC San Diego Center for Healthy Aging. Because people have less body water as they get older, “if you drink the same amount at 80 as you did at 30, your blood alcohol level will be much higher.” In that scenario, one drink can have the same impact as two or three did when you were younger, causing you to feel intoxicated much sooner.

Keep in mind: At any age, women are more susceptible to the effects of alcohol because pound for pound women have less body water than men do. Women also have less of a stomach enzyme that helps with the metabolism of alcohol, Moore says. As a result, if a man and a woman who each weigh 150 pounds drink the same amount of alcohol, the woman will have a higher blood alcohol level than the man will. While this is true at any age, it also means that women will be even more susceptible to the effects of alcohol, as they get older.

Meanwhile, people’s ability to metabolize alcohol changes as they get older because the activity of certain enzymes—alcohol dehydrogenase, aldehyde dehydrogenase, and cytochrome P450 2E1—that process alcohol diminish with age, says Olivera Bogunovic, an assistant professor of psychiatry at Harvard Medical School and medical director of the Alcohol, Drug, and Addiction Outpatient Program at McLean Hospital.

As a result, “the effects of alcohol build up faster and last longer,” says Stephen Holt, an addiction medicine specialist and associate professor of medicine at the Yale School of Medicine.

The brain also becomes more sensitive to the effects of alcohol as people get older, Moore says. “This can make people more prone to developing problems with coordination or balance,” increasing their risk of falls. It also can impact judgment, reaction time, and driving ability.

Taken together, “all of these physiological changes add up,” Weaver says. “It’s a gradual change over time during adulthood.”
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Credit: National Geographic