Five mornings a week, Dr. David Slotwiner, the chief of cardiology at NewYork-Presbyterian Queens hospital, can be found tending to human hearts.

But on Sunday mornings, he is on a grass-covered field at a rural farm in Hackettstown, N.J., standing among half a dozen sheep, whistle in hand, teaching his Border collies Cosmo and Luna to herd.

“It helps me think about what it takes to be an effective leader, though doctors don’t respond to whistles very well,” said Dr. Slotwiner, 58, who specializes in cardiac electrophysiology.

He started coming to the farm during the coronavirus pandemic, after Cosmo began showing aggression and bit his wife, Anne Slotwiner, 60. A trainer recommended a small sheep farm in New Jersey, Wayside Farm, that trains Border collies — and, once he herded with Cosmo for the first time, he was hooked.

Dr. Slotwiner shares a three-bedroom house in Pelham, the oldest town in Westchester County, with his wife, Cosmo, Luna and a 15-year-old American Eskimo rescue, George. (He has two adult sons, Harry, 28, and Peter, 25.)

SLEEPING IN, KIND OF During the week, I get up around 5 a.m., but on Sundays, I’ll sleep until 6:30 a.m. I’m not a morning person, but I’ve been forced to be a morning person. I’ll start the day by reading The New York Times on my iPhone in bed.

RISE AND RIDE I go to a 7:30 a.m. SoulCycle class in Bronxville. It’s always timed to the rhythm of the music, which makes it different from other spin classes. Before the pandemic, I was often taking six classes a week, which was not healthy.

MORNING MEET-UP Around 9 a.m., I meet my wife for breakfast at Caffè Ammi in Pelham. She’ll have the dogs in her car, because my car isn’t quite big enough to take them out to the farm in. I’ll get a large whole milk latte with one sugar and a warmed-up cranberry scone and — if I’m feeling decadent — an almond croissant.

OUT TO THE FARM I drive about an hour and 15 minutes to Wayside Farm. I’ll listen to a podcast on the way — I love “Hard Fork” and the NewYork-Presbyterian podcast “Health Matters.” And I really enjoy John Mandrola’s “This Week in Cardiology.” He’s a bit of a curmudgeon and always is slow to adopt new technology, and so I like to hear his critical perspectives. I tend to be a little bit of an earlier adopter, but I like to hear the science of both sides.

WHISTLE WHILE YOU WORK We arrive at the farm around 11 a.m., and I grab my whistle and put on my headset — the distances are very great across the field, so this is how I can hear the people training me — and head out on the field with Cosmo and Luna.

Gene Sheninger and Teri Rhodes, who own the farm, train people to the highest level of competition internationally, but they’ll also take novices. There are other herding breeds, but Border collies tend to be the most common and tend to be the best for sheep.

BABY STEPS The first thing you teach them is to go clockwise, which is called “come by,” or counterclockwise, “away.” And then you teach them to drive the sheep to you in a straight line, in a controlled way, so they don’t push the sheep so quickly that they scatter. And then you teach them to push the sheep beyond you, which is one of the hardest things to get them to do, because Border collies want order — they don’t want the sheep to escape.

The ultimate challenge is to teach the dog how to separate the sheep into two groups, because the sheep instinctually want to stay together as a herd.

TOOLS OF THE TRADE Once you’re a certain distance away, you have to give commands using a whistle. In competitions, sometimes you do this over 800 or 900 yards, where you can’t even see the sheep. But the dogs learn to trust you so much that they know that if you give them the command to go clockwise, even if they don’t see the sheep, they will go clockwise to the edge of the field and keep running and running and running until they find those sheep, and then they will bring them to you.

NEWBIE NOSTALGIA It’s great to be a novice at my age, because I’m teaching medical students and residents every day. I’m teaching attending cardiologists how to do invasive procedures. It’s refreshing to be a beginner at something, to remember how it is to learn as I’m teaching people.

GETTING IN THE ZONE I’ll pack up around 12:30 p.m. or 1 p.m., then hop into the car and finish my medical podcast on the way back to Pelham. It helps me get in the mind-set for work.

DUMPLING DETOUR If I’m on call at the hospital, which I am every fourth weekend, I’ll head to downtown Flushing to grab a bite to eat before my shift. I love the soup dumplings at Juqi.

DR. BOW-TIE WILL SEE YOU NOW I arrive around 2 p.m. and change into scrubs. I’ll usually have four or five patients to check up on, and then I’ll take care of some paperwork or review a manuscript or two.

I’m typically rocking a bow tie. Fifteen years ago, a patient gave me one, and I decided I’d give it a try. It took me a while to figure out how to tie them — it was a lot of YouTube videos — but then I would wear it occasionally, and my patients really liked it. So then I went all in on bow ties. I have more than 50.

DINNER DATE Around 5 or 6 p.m., I’ll head back to Pelham to pick up my wife, and we’ll meet our son Harry and our daughter-in-law for dinner in Williamsburg. One of our go-to places is Ringolevio. If I’m splurging, I’ll have a skirt steak and a glass of red wine. Or I might meet my parents, who live in Battery Park, at a Greek restaurant down the block from them, Anassa Taverna. I love the grilled branzino, with white wine.

FUN WITH FRISBEES You can’t just come home to Border collies and say, “OK, it’s time to go to bed.” They’ve been herding for an hour and a half to two hours, and they’re working hard. So I’ll come home and play Frisbee with Cosmo and Luna for around half an hour. Cosmo is very toy motivated. Luna mostly wants affection and interaction.

KINDLE TIME I’ll climb into bed around 11:30 p.m. and read for half an hour on my Kindle. Right now I’m reading a Tana French novel, “Faithful Place,” which I’m enjoying. It’s a book to clear my brain. I’ve also finished another book that I really love, Barbara Kingsolver’s “Demon Copperhead.” I love the feature where you can switch between reading on the Kindle and listening to it, because that way, when I commute, whether it’s to work or to the farm, I can continue it.

OUT LIKE A LIGHT I usually fall asleep close to midnight. I’m a night owl. But I don’t go to SoulCycle on Monday morning, since I’ve had the whole weekend to exercise, so I don’t have to get up until 6.