Consider these scenarios: A lady walks into a party and has one glass of champagne. She’s what public health experts call a moderate drinker.

A gent enjoys same party and has two glasses of wine. He, too, is defined as a moderate drinker.

But should either of them reach for another glass, they’ve just poured themselves into excessive drinking territory, by medical standards. And if she hits four drinks or he reaches five, they’re on a binge.

Binge drinking — a behavior oft-ascribed to college kids — is more widespread than you might think, public health and medical experts say. One in six American adults report binging about four times a month, according to the Centers for Disease Control and Prevention.

Here’s the surprise: Roughly 70 percent of those episodes involve adults ages 26 years and older. And elderly binge drinkers report the most frequent episodes, an average of five or six a month. The average binge involves eight drinks.

But all that over-indulgence is according to the standards of the medical profession. Ask the average person, and they may have a different formula altogether.

Steve Power, of Conyers, Ga., jokingly defines binge drinking this way: “When I drink liquor and get drunk trying to forget the day that I had.”

Drew Costanza not only quibbles with the doctors’ definition — he disputes the assumption that getting hammered from time to time is necessarily a problem.

“I feel the phrase ‘binge drinking/drinker’ is pejorative in that it alludes to drinking excessively as being necessarily bad, when that isn’t always the case,” said Costanza, a 30-year-old salesman in Atlanta.

Costanza considers himself a “weekend warrior,” one who reserves most hard-core drinking for the weekend. He also walks to his watering hole or takes a cab, he said.

Costanza also writes a blog about his outings titled “Drew Distilled.” He thinks the five-drink-per-man definition discounts variances in drinkers’ tolerance.

“I doubt Andre the Giant would think five drinks a night is a binge,” he said.

Dr. Bob Brewer, an epidemiologist and head of the CDC’s alcohol program, is accustomed to such push-back. “A lot of people are surprised by that ... and say ‘Wow, that is really strict,’” he said.

But health experts, who get paid for this kind of thing, are sticking to their numbers: For men, a binge is five drinks in roughly two or three hours; for women, four drinks.

There’s actual science behind those sobering figures: That’s roughly the amount it takes for a woman or man to reach a .08 blood alcohol level.

And “it’s the statistical threshold at which the risk of significant harm goes up,” explained Aaron White, a neuroscientist with the National Institute on Alcohol Abuse and Alcoholism.

Research shows that at those levels, people are at greater risk of all kinds of bad outcomes, such as motor vehicle accidents, violence and contracting sexually transmitted diseases. And that’s not accounting for what alcohol does to your liver and how it increases your risk of heart disease, doctors note.

“It doesn’t mean at that threshold you are guaranteed to suffer some consequences,” White said. “It means if you go past it, it’s dangerous territory.”

Experts acknowledged a vast gap between their cautionary approach and the messages that pervade American culture.

“We market drinking as a social lubricant,” said Paul Olander, director of behavioral health services at the DeKalb Medical Center. “As a way of celebrating, it goes along with dates and with romance and wining and dining and watching sports and all kinds of things. It’s to the point that it can seem like without (alcohol), those activities aren’t quite as good.”

The medical professionals say they’re not trying to make anyone feel bad — just aware of the potential risks and consequences.