I'm a woman in my 40s. Why do I feel terrible every time I have a drink?

This summer an old high school friend of mine decided to quit drinking entirely. She didn't want to, but she felt she had no choice.

"All of a sudden my body decided that alcohol is poison," she told me recently over a bitter grapefruit mocktail at an Italian restaurant. "I can have as little as one drink, and I have a hangover."

Like me, my high school friend was never a heavy drinker. She enjoyed having a glass of wine with dinner and a craft cocktail or two at a bar or restaurant with friends. If she had several drinks in a night she would expect to feel sluggish in the morning, but one or two was never a problem. Then, sometime in her mid-40s, her ability to tolerate alcohol plummeted.

"It's that feeling of regret," she said when I asked her about her post-drinking symptoms. "Headache, fatigue, I don't know how to name that feeling in your stomach."

The last time she had a margarita she felt so terrible that she ended up canceling her plans the following evening.

It's a story I've been hearing from a growing number of my female friends since we entered our mid-40s a few years ago. Molly finds drinking wreaks havoc with her digestive system and her sleep. Alexis loads up on water and Motrin even if all she's had was a half-glass of wine. Naama, who still makes the world's most delicious batch cocktails, stopped drinking a few years ago after getting the sweats and a splitting headache halfway through a vodka soda.

I've experienced it as well. After even one joyous drink, I find myself waking up at 3 in the morning with a dull ache in my stomach, wishing I'd made a different choice. Now, each opportunity to grab a beer at a barbecue, enjoy a cocktail at a restaurant or sip a glass of wine at a dinner party requires a cost-benefit analysis: How much do I want a drink now versus but how much am I willing to pay for it later?

To understand why my friends and I are finding alcohol more difficult to tolerate as we age, I reached out to George F. Koob, director of the National Institute on Alcohol Abuse and Alcoholism.

Koob pointed to studies that show that women are more sensitive to the toxic effects of alcohol — developing alcohol-related liver disease and high blood pressure due to drinking at higher rates than men — but added that scientists are still working out why that seems to be the case.

"This is a new area of research," he said.

While Koob wasn't aware of studies that looked specifically at how a woman's ability to metabolize alcohol changes in middle age, he said any changes may be due in part to the natural and inevitable fact that our lean muscle mass decreases and our body fat increases as we get older.

Alcohol is drawn to water, Koob explained, and lean muscle mass has a higher percentage of water than fat does. Lean muscle mass, then, gives alcohol more space to dissipate throughout the body, making for less of it in the bloodstream, and a lower blood alcohol concentration. But as we age and lose lean muscle mass and gain fat, a higher concentration of alcohol winds up in our bloodstream. That makes for worse hangovers and extended recovery time.

"You might drink the same amount of alcohol that you used to drink, but now that one drink is more like having one and a half or two drinks, because the alcohol is hanging out in the bloodstream," he said.

If it makes you feel any better, men also lose lean muscle mass and gain fat as they age, but men's bodies have a higher concentration of water (55% to 65%) compared with women (45% to 50%) to begin with, so the effects may not be as obvious as they are for us.

Koob supports finding alternatives to drinking — "If you feel better when you don't drink, then listen to your body," he said. If you are going to drink, he offered that eating a snack beforehand can slow down the body's absorption of alcohol and help blunt the irritation to the stomach that can cause the icky feeling I know so well. He also advised against using ibuprofen immediately after drinking, because it can also irritate the stomach. Drinking extra water will help dilute the alcohol, but ultimately, it's the amount of alcohol you drink that will affect how you feel, not how much water you drink.

Because my friends and I are also firmly in the perimenopausal phase of our lives, I called up Dr. Monica Christmas, associate professor of obstetrics and gynecology at the University of Chicago and associate medical director of the Menopause Society, to see if our new challenges with alcohol might be related to hormonal changes as well.

The answer was a resounding yes.

She explained that alcohol triggers or exacerbates many of the symptoms of both menopause and "the menopause transition," which can begin seven to 10 years before a woman's period actually stops.

For example, 40% of women report mood instability during the menopause transition, which can include increased anxiety, depression, or not being motivated to do the things they once did.

"Alcohol exacerbates those things," Dr. Christmas said. "So if you're already experiencing mood instability, you're only going to feel that much worse when you drink alcohol."

I haven't noticed my anxiety skyrocketing after having a drink or two, but my high school friend said that sounded familiar.

"There was an evil loop I was in, where I was like, I'm really anxious, maybe I'll have another drink," she said. "My husband was like, how's that working out for you?"

To be clear, not all my friends feel this way. Some who have always consumed alcohol more regularly looked at me quizzically when I asked if they find it harder to drink these days. It's possible they have developed a physiological tolerance to alcohol or may just be more used to hangovers, said MacKenzie Peltier, an assistant professor of psychiatry at Yale School of Medicine who studies sex differences in alcohol abuse disorders. It might also be that their experiences of the menopausal transition or aging are different. "But that's complete speculation," she said.

As for the rest of my friend group, we're all handling this frankly unwelcome change in different ways. My high school friend has become a mocktail connoisseur. Molly hasn't cut out alcohol completely, but she does do dry months to give her body a break. Alexis recently decided not to drink during the week anymore, but weekends are still up for debate. Naama is always on the hunt for a fancy nonalcoholic drink with low sugar content to sip at celebratory occasions.

"The only time I miss it is when we're out with friends and the only option is Diet Coke," she said. "And God forbid if that option is only Diet Pepsi. Then I'm really screwed."

As for me, I'm trying to minimize the temptation to consume alcohol. Not only are pre-dinner cocktails expensive from a financial standpoint, they're costly from a health perspective, too.

I do still love to have a drink at my Italian social club, however, and if that means a couple of rough nights a month in order to enjoy an Aperol Spritz or two — for me, that's a trade-off I'm willing to make.