‘Dogs Are a Good Example of Healthspan’

In my presentations about the Dog Aging Project, I often talk about our dog Frisbee. When we met her, she was in a crate outside of a pet store, having been rescued as a puppy. Her name was an aspirational name from our kids, who were confident they’d train her to be a frisbee-catching dog. That never happened, but the name stuck.

As our family likes to say (and we have it on empirical grounds), Frisbee was the best dog ever. She exuded joy: to any new person who came to the house, her message clearly was, “Welcome! I’m so happy you’re here! Let’s play!” She was a mutt, about 45 pounds, and lived to 16-and-a-half… a very long lifespan for a dog her size, like a human living to 100.

If your dog is fortunate enough to live into her geriatric years, it can be an incredibly difficult thing to watch her age. Aging unfolds in a unique way in each person, and across each species, from insects to fish, from birds to mammals. They all age in their own way.

And yet there are common elements. So, when we watch a dog aging, it's a lot like the aging that we see in our human loved ones. We might see the decline in vision, or in cognitive function, or in mobility. Even as Frisbee moved into her later years, at 11 or 12 years old, she hiked with us in the mountains—she was incredibly active. And then she started to slow down. We almost lost her at 14 to a serious bout of pancreatitis. She had cataracts. She had mild cognitive impairment. She had osteoarthritis.

Clearly, Frisbee experienced multiple challenges as she grew older. This is one of the challenges that we experience in our own lives as we age—what we call multimorbidity, transitioning from no chronic conditions to one chronic condition, and then often to multiple chronic conditions.

In the field of geroscience—the study of the biology of aging—an important open question is whether underlying mechanisms of aging lead to multimorbidity, or multimorbidity leads to aging: which way do the causal arrows go? We don't really know, but we do see this process unfold in dogs, and it happens much more quickly.

Healthspan Versus Lifespan

Many of my colleagues in aging research are trying to understand ways not simply to increase lifespan, which could mean more years with disease, but rather to increase the duration of healthy lifespan; we call it the lifespan/healthspan distinction. 

Dogs are a good example of healthspan. We can clearly see when their healthspan ends, when they no longer have a reasonable quality of life. With older dogs, it sometimes feels as if they’re able to tell us when they can no longer do the things they love to do.

When I was in college, I hoped to have a career that would help me connect people. Working on aging—and certainly, working on the Dog Aging Project—has helped me to realize that goal. In fact, I think of the Dog Aging Project’s participants, who live in every state in the U.S., as a 51,000-strong team of community scientists.

And, importantly, when people go to the dog park and connect over their shared love of dogs, they often get to know each other really well and even become close friends. And regardless of politics or family background or religion, they connect over dogs. That's an important thing the Dog Aging Project does: it brings thousands of people together because they share a love of dogs.

I'm not sure I think more about aging than anybody else who's aging because, of course, we’re all aging. But I do think a lot about aging. I am certainly aware of things that we can do as individuals to increase our chances of being healthy into our older years. I think a lot about that now that I have a two-year-old grandson. I want to be able to take him hiking in the mountains here in New England when I’m in my 70s and maybe even 80s. What can I do now to make sure I get there?

I'm 61. I definitely feel a lot younger than how I perceived my grandfathers to be when they were 61. On average, we are definitely healthier now than they were when they were in their 60s. Our life expectancy is greater now. I'm not sure I could put it in years, but I feel great. I love, for example, that I can ride my bike to work at Tufts every day and will continue to do it as long as I can.

I also think about the things that I can do—and that we all can do—to ensure that we live the healthiest, long life possible.

There are things that we cannot control. We can't choose our genes; our parents effectively did that for us, and that accounts for about 25 percent of the variation in how long we can expect to live. Then there's a lot of random stuff that we have no control over.

But what we can do is ensure healthy diet, regular exercise, healthy sleep patterns, no more than moderate use of alcohol (and no hard drugs), and healthy social interactions. Those are five things that we all can do to maximize healthy lifespan. Although I am a biologist, I do wonder whether there are public health measures that we can take to help all of us in this country live the healthiest long life possible, by optimizing diet, exercise, sleep patterns, drug or alcohol use, and social interactions. I believe there are, and I believe we should.

—Daniel Promislow, senior scientist and scientific advisor, Jean Mayer USDA Human Nutrition Research Center on Aging, and principal investigator and co-founder, The Dog Aging Project

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