I spend about two hours every Sunday morning with people I almost never see fully clothed.

Rain or shine (I prefer shine), hellishly hot or bone-chillingly cold (I prefer hot), we gather in a parking lot just off Duke Forest to do a long run together. Many of us run solo six days a week. But Sundays we become a pack.

A little before 8, we start to arrive; often the more hard core have already jogged a few miles to warm up. You never really know who is going to show, but you know there'll be someone to run with for 9, or 13, or more miles. And I know that I can look forward not only to a bracing run, but to bracing conversation on, among other things, local politics, affirmative action, the shortlist for the Booker Prize, college basketball, and academic gossip.

For most of my life, I was an anti-runner. In college, all of my friends jogged. When I lived in New York, my best friend never missed her morning six miles. Once, while I was on vacation with a friend and another couple, the three of them went out to run on the beach for an hour. I stayed and lounged on the deck in my black bikini, eating Oreos and reading a novel. I thought they were nuts. I was an intellectual, not an athlete. I often repeated to myself (and to those around me) a comment that a fellow editor at Oxford University Press made many years ago, when I asked him about his exercise routine: "People should look like what they do. I'm an editor. I sit and read."

It happened accidentally. I began running with Andrew, an academic psychiatrist, because I thought my dog needed more exercise. We started out with a three-mile loop around Duke's golf course, which is God-awful hilly. I couldn't run the whole way. At times, when faced with a big hill, I'd bark out, "Tell me about schizophrenia!" or "What the hell is serotonin, anyway?" A natural and amusing pedant, Andrew would then give me a minilecture that was so engrossing and diverting that we'd crest the hill before I knew it.

When I met Peter, I was transformed from a jogger to a runner. Peter, a zoologist, had been the women's-track coach at Duke in the dark days before Title IX. He's a great coach, and a good runner. His wife, Martha, is a great runner. When she was 39, in her first marathon, she broke the North American record for her age group. Peter once invited an extremely famous Harvard biologist to come to Duke. The man showed up ostensibly to give a talk on animal behavior, but the real reason he accepted the invitation was because he thought that Martha could pace him to a sub-six-minute mile.

Twenty years ago, Peter trained for a marathon with three other fiftysomething academics. During their weekly long runs, they took turns lecturing. Henry, a physicist, explained how quarks were discovered. Peter talked about his work on maternal-infant attachment. Seth, a topologist, would draw mathematical figures in the dirt when the group stopped for water, and Orrin, a geologist, would drive the course the night before in order to coordinate his talk with appropriate geological illustrations.

On my runs with Peter, we've discussed the civil-rights movement, Quakerism, political correctness, science and the "science wars," Wittgenstein, mutual friends, books, music, film (though this is a man whose favorite movie is Babe, so we don't spend too much time on film), and have had some high-voltage arguments (often, it seems, just for the sake of arguing, since we basically agree on most things). It's never personal, and it's always stimulating. Our arguments tend to make us run faster; when we run with others, however, our companions often try to change the subject.

I am not a joiner. I joined a running club, even became an officer. And I started showing up, religiously, for the long runs on Sunday mornings.

I knew that Ole was a famous professor of political science at Duke. But it wasn't until we began running together on Sundays that I learned Ole's father had been Finland's first foreign minister and the country's ambassador to the League of Nations. That's how Ole happened to be born in Geneva. When the league collapsed, the family came to the United States in the 1940's, and Ole grew up as a Stanford faculty brat.

Ole has tons of interesting and funny opinions on a wide array of topics. One of my favorites is a proposal to get rid of Duke's less-than-spectacular football team and replace it with a bunch of scholarships for track, since we all know that runners are the smartest of athletes. Ole's an excellent political scientist, a much-loved teacher, a great father, husband, colleague, and friend. But what is he really? A runner. He has run every day (at least once a day) for the past 10 years. Nothing stops him, not professional obligations (he has student conferences over five-mile runs), not family interactions (his daughter, Maija, is an extremely talented triathlete -- they ran a race the morning of her wedding), not even surgery.

My friend Paul is a professor of marketing at the business school at Chapel Hill. When I was involved in revising Duke's "viewbook," the publication sent out to prospective students, I ran with Paul for a couple of Sundays to talk about my ideas. He has done research on college-marketing issues. He told me how to conduct focus groups to find out if our concept would work with high-school kids, and generally served as a consultant. So it was that rival U.N.C. donated thousands of dollars of professional advice to help Duke recruit the brightest undergraduates.

The back of the Sunday pack is a wonderfully interesting place, and when I'm tired, I love to run with Walter, an epidemiologist. His work has taken him all over the world, and he manages to plug into the global network called the Hash House Harriers (bunches of people who describe themselves as "a drinking group with a running problem") wherever he is, be it San Francisco, Taiwan, or Copenhagen. Walter often runs with Jim, a pilot, whose dad was a statistics guru at U.N.C. Turns out that Walter and Jim, good buddies, had both been involved in a long-term relationship with the same woman (sequentially, not simultaneously). I know more about Louise than almost any other person I have never met.

During a recent five-mile race, I held poor Bob captive. Not only is Bob an outstanding political scientist (for some reason, our running group is rich in political scientists), he is also married to Duke's president. There were a number of things that I wanted to discuss with him, so I ran by his side, chatting away. He kept saying, graciously, that he didn't want to hold me up, that I should feel free to go ahead (he'd not been running much recently, but he is pretty speedy for an older guy). No, I said, this is fine. Finally, as we were climbing a hill, I asked him to tell me about his current scholarly project.

"I can't discuss that with you now."

Wow. I was surprised. Was it top secret? Was I being nosy and rude?

A couple of strides later he said, "I'll tell you when we stop. I can't talk. I can hardly breathe. You can talk.

Some Sunday mornings, I'll start out running with Owen, a computer scientist, who usually runs too fast for me, but warms up slowly enough that I can keep pace for a mile or two. It's always worth it. I once had a Duke applicant, in an interview, tell me that one reason that he was applying to the university was because he wanted to meet Owen. His high-school class had used Owen's computer-science textbook, and the author seemed like a funny, quirky, wacky guy. The applicant was right.

On Sunday mornings, we have statisticians, engineers, psychiatrists, psychologists, lawyers, public healthers, biochemists, investment bankers, neuropharmacologists, geneticists, airplane pilots, physicians, software developers, veterinarians. All people you want to talk to. The main thing that decides whom you get to chat with is how fast (or slowly) you want to run on that particular morning.

The running boom has been going for a while now; it may even have already busted. But from the beginning, long-distance runners tended to be eggheady sorts. Part of it, I think, comes from the need to be able to spend hours alone with your own thoughts. Even though I do a lot of socializing on runs, I also do a lot of thinking. If there's a problem I want to ponder, I go for a solitary run. I usually come home having made mental progress.

Some people may consider a weekly Sunday-morning half-marathon as, at best, an exercise in self-punishment. Most of the academics I run with think of it as a luxury, along the lines of taking two hours over coffee. It's a necessary and fun part of their social lives. When else, I often ask myself, would I get a chance to see and talk to these people? Certainly not once a week, probably not once a month. But every Sunday, I get a window of privileged time, an opportunity to be with people I like, and respect, and admire, and learn from. All we do is talk (and run).

During a recent marathon, at mile 16, I ended up on the heels of two men. One, obviously a physician, was describing to his friend how he and a bunch of other doctors had set up an H.M.O. He explained the challenges and described how the enterprise eventually went belly up. It was a fascinating conversation, and I thoroughly enjoyed eavesdropping. Was there a difference in health-care delivery when the docs were in charge, I wondered? I was about to ask, and then, suddenly, it hit me. This wasn't a Sunday-morning run. This was a race. I had a time goal and couldn't afford to waste my energy in dialogue. I left them behind after a mile or so, having said not a word, but looking forward to the opportunities presented on my next Sunday-morning run.

You know what? My editorial colleague was right: People should look like what they do. I'm a runner.

Rachel Toor, a former book editor and admissions officer at Duke University, writes frequently for The Chronicle.

http://chronicle.com Section: Opinion & Arts Page: B7