The Current - What can we learn about human aging from dogs?

Episode Date: December 10, 2025

A study looking at over 50,000 dogs in the U.S. is aiming to understand how they age, and what clues dogs can tell us about how humans age, too. We speak with Daniel Promislow, one of the co-founders of the Dog Aging Project, about the genetic and environmental factors that allow dogs to age healthily.

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Donate at lovescarbro.cairbo. This is a CBC podcast. Hello, I'm Matt Galloway, and this is the current podcast. At this dog park in Vancouver, despite the rain and the gray clouds, it is playtime for some of the city's pups. Dogs are our most faithful companions. But like all good things, they come to an end. And that is why a study in the United States is looking to find out more

about how dogs age and how they might live longer, something these pet owners very much like the sound of. Living the world, yeah. Yeah, they don't live long enough for sure. It's a part of the family. I'm hoping to go out about the same time he does, so we can both live longer. Yeah, that would be great.

I'd like to keep them as long as I can. Oh, it would be the most important thing. If there's anything we could do to make them more healthy and help them live longer and live them more healthy, then of course. It'd be absolutely wonderful. I mean, one of the hardest things in life when you have pets is that you usually outlive them. And it's just, the grief is horrible.

It's overwhelming. And, you know, if they could live longer, it would mean everything. I lost my 16-year-old puppy, like, two years ago. Even to improve the quality of her life in the last few years would have been amazing. Daniel Promisloe is one of the co-founders of the Dog Aging, project. He is a senior scientist and scientific advisor at the Human Nutrition Research Center on Aging at Tufts University in Boston. Daniel, good morning. I'm delighted to be here. Very glad to have you here. People love their dogs, but one of the things about adopting a dog is that you're

often told that this is in some ways like delayed or deferred heartbreak because you know what's going to happen at the end. What do we know about how long dogs live? Not long enough. That's Definitely true. We also know that lifespan in dogs is very breed specific, so for the purebred dogs and the mixed breed dogs, in general, the larger breeds don't live as long as the smaller breeds. So the giant breeds, some of them might live six or seven years, and some of the toy breeds can live 15 or 16 years pretty easily. And then there's certain breeds that seem to do better than others. I always like to say that the right Dog for someone is not necessarily based on how long it lives, but just how you feel about that dog, just like choosing a human partner. What do we know about how quality of life deteriorates as dogs age? It's very much like people. A lot of things fall apart as we age, and that's true of dogs as well. And one of the things that we talk about in aging research a lot is the idea of health span. The goal is not just to maximize lifespan or longevity, but healthy lifespan, the number of years

free of chronic age-related conditions. And that's our goal in dogs as well. Just to tell you an anecdote, we had a dog Frisbee who I think was the best dog ever, but as she got older, she really struggled with a lot of things. Her pancreas didn't work. She had vision problems, cataracts, cognitive problems, and she really struggled with osteoarthritis, and that's a big problem for a lot of dogs as they get older. And so you heard those dog owners in the park there talk about how this kind of research would mean so much to them. You're tracking dogs over their lifetimes.

Tell me a little bit about the research that you're doing. Sure. So the dog aging project is a community science project. We've engaged more than 51,000 people around the United States who share information about their dogs. We have a whole set of surveys that they, fill out every year and we're following each dog for as long as it lives, the real power of the study is that by observing dogs year after year and watching how they change, we can

understand what it is about what dogs and our owners are doing in early life and middle life that maximizes that health span. And so we're five years in. We have a lot of information already. And one part of it that I think we can talk about today is about one percent of the dogs are also enrolled in a clinical trial testing whether a drug that has been seen to increase health span in the lab might actually also increase health span in dogs in the real world. What does that drug do? It's a drug called rapamycin.

It's commonly used in human transplant patients at much higher, relatively high doses to help prevent rejection. But in low doses, in lab organisms like mice, it makes them live low. longer and stay healthier longer. The drug itself does quite a bit of things. It's called rapamycin, and it affects a pathway that we call the target of rapamycin that is found in all of our cells. But the important part is that, at least in the lab, it seems to increase healthy lifespan, and we're testing that ability in dogs. So we have what's called a double-blind placebo-controlled study. That means that we don't know what the dog is getting and the owner doesn't.

That's really important. So there's no bias there. And half the dogs are on placebo. Half the dogs are on the actual drug. We're giving it to them for a year at very low dose and then we follow them for two additional years. And after three years, we'll know if this drug helps dogs live healthier longer. And do we have any sense as to what kind of dogs? I mean, at this point, would be best suited to using a drug like this? Well, for now, we are limiting enrollment to middle-aged and older large breed dogs in this particular clinical trial, and that's just because, as I mentioned earlier, the small-breed dogs live for a long time.

And so if we enrolled dogs that are going to live 15 or 16 years, we'd be waiting 10 years before we hadn't answered. So right now, we're just testing it in the shorter-lived larger dogs. if it works, then we might want to test it in the small dogs as well to see if all dogs would benefit. Can I go back to the idea of the health span versus lifespan? I mean, I want my hound to live as long as possible. He's a tornado, but he's great.

But part of being a pet owner is also having to make these awful calls about when you need to let those dogs go. You talked about Frisbee and the difficulty that the dog was experiencing at the end of its life. Is this a good thing to try to stretch out a dog's life? So by health span, what we're talking about is healthy aging. So the goal is not to stretch out years of suffering, but to prevent or delay the onset of that suffering.

And we already know in people, for example, there are some really simple things that we can do to maximize our health span. Healthy diet, regular exercise, good sleep patterns, social interactions, all of those things help people live longer. And we think from our research that the same is likely to be true in dogs. So we're not advocating that you try and keep dogs going when they're suffering at all, but to delay the onset of that suffering so that we can have more happy, healthy years together.

Yeah, I just wonder, you know, inherently there's going to be tension around that, right? People want their dogs to be around as long as possible. people are cloning their dogs after they die because they want the, you know, the dog to still be there even though the dog is gone. You could just imagine that there will be tension that plays out in terms of how people understand the value of this. Sure. Let me just add one more thing to that. One of the really amazing things about studying dogs is that owners and veterinarians know those dogs so well. And dogs will really indicate to us what the quality of their life is. And euthanasia is such a hard decision. But it's

not taken lightly by the caregivers. And we know, and dogs will let us know, when their quality of life is really low and maybe not worth living. And so unlike in people where we do want, we tend to prolong our lives and many people live with years of struggle, in a way, the duration of life in a dog really is a measure of the quality of its health span, because when that life is not worth living, we very thoughtfully work with our veterinarian to recognize that and recognize that the time of the end of life has come. We aren't dogs, of course, but is there anything that we can learn from this study in terms of our own lifespan and health span?

Oh, for sure. Dogs are really an amazing model, not just for dogs, but for us. Unlike all these laboratory organisms, they live in our environment, they get the same diseases that we do. They're genetically variable like we are, and they have the sophisticated healthcare system just like we do with specialties like cardiology and neurology. So I think they're actually the best model to not only to help us learn how to help dogs, but also to help us learn how to help us live healthy long lifespins. You have a dog? Oh yeah. We had a dog. Just making sure it would be awkward if the guy who's running the dog aging project is actually a cat person.

No, and I have to say I'm speaking from home and I've picked a room in the house where the dog can't see outside right now. The blinds are closed. Otherwise, you'd hear a lot of barking in the background. What's your dog's name? Our dog's name is Pete.

Excellent. We have a rule. If people talk about their dogs, we have to find out what the dog's name is. Daniel, this is really interesting and you can imagine a lot of people will be paying very close attention to your research as it unfolds.

Perhaps we'll check back in down the line. In the meantime, thank you very much. Sure, let me just add if your listeners would like to learn more, just check out dog aging project.org. Fantastic. Thanks so much. Thanks, Matt. Great talking to you. Daniel Promisloe is one of the co-founders of the dog aging project. He is a senior scientist and scientific advisor at the Human Nutrition Research Center on aging at Tufts University in Boston. This has been the current podcast. You can hear our show Monday to Friday on CBC Radio 1 at 8.30 a.m.

at all time zones. You can also listen online. at CBC.ca.ca slash the current or on the CBC Listen app or wherever you get your podcasts. My name is Matt Galloway. Thanks for listening. For more CBC podcasts, go to cBC.ca slash podcasts.