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When is a Dog Considered a Senior? Breed, Size, and More

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It should be easy to tell when your dog has reached or is close to senior status, right?

If you’ve had your dog since they were a puppy, you probably know their birthday (or at least an estimate of which month and year they were likely born in), which obviously helps a lot with knowing when a dog is considered senior.

Aside from calendar age, there are often physical signs that indicate a dog’s age as well; grey muzzle hairs and overall being less active than before are all part of being an old dog. But your pup’s breed, genetics, environment, diet, activity level, and overall health can also affect their estimated age. In short, the number of factors that go into determining when a dog is considered a senior is more than just a simple one-size fits all calculation of “one dog year equals seven human years” (but we’ll get into that more later on in this article).

If you have a rescue dog where you’re unsure of their breed (or breed mix) and overall medical history, or you just want some ways to confirm your pup’s age, this article goes through the various ways you can answer the question, “when is a dog considered a senior?”

By knowing the signs that your dog is getting a bit long in the tooth, you can better understand their changing health needs.

When Is a Dog Considered Senior?

Have you ever heard a (human) doctor say that you have the fitness level of an 80-year-old or that the wear and tear on your joints is similar to someone in their 60s? 

Vets use similar logic when trying to estimate when a dog is considered a senior. They’ll look at the condition of the dog’s teeth, move their legs to check the wear and tear of their joints, test their reaction time, and check their vision. The sum total of this information gives the vet a roadmap that provides clues as to how long the dog has been around, as well as their general health.

Blood, urine, and even feces tests can give a vet more information about your dog, including their breed type(s), internal organ condition, nutritional status, and digestive health. 

At What Age Is a Dog Considered a Senior?

Dogs age differently depending on their breed, genetics, nutrition, and overall health. Certain breeds of dog age “faster” because of their unique body structures and genetics.

Larger breed dogs tend to have shorter lifespans compared to smaller breeds. Large and giant breed dogs are at a greater risk of developing life-threatening health issues earlier than smaller breeds.

For example, deep-chested, large, and giant-breed dogs are at a greater risk of developing gastric dilation volvulus, an often fatal condition where the stomach fills with gas and then twists upon itself, blocking its entrance and exit. This condition can technically happen to any dog, but large-breed dogs are up to 10 times more likely to get it. 

An interesting article by Inside Science discusses the differences in how dogs age, specifically how a dog’s size relates to aging. In the article, Cornelia Kraus, an evolutionary biologist at the University of Göttingen in Germany, and her team hypothesized that either:

  1. Large dogs age faster
  2. Large-breed dogs start aging earlier compared to small breeds
  3. Large dogs simply have a higher mortality risk compared to smaller breeds because of their increased susceptibility to life-threatening diseases

To test these theories, the researchers analyzed over 50,000 dogs from 74 breeds taken from the Veterinary Medical Database, which compiles pet health data from North American veterinary teaching hospitals.

When the dog breed data from the database was graphed, the “mortality curve” closely matched the faster-aging hypothesis. Other studies on the IGF1 gene, which is a growth hormone that is found in a large number of organisms, including humans, that seems to be associated with age-related diseases like cancer and heart disease, as well as aging rates, have found that small dogs have less of this hormone, and large dogs have more of it. In other words, less IGF1 gene equals a small dog, more IGF1 gene equals a large dog.

The key takeaway is that if a dog gets bigger faster, it affects their potential lifespan with a higher rate of aging and an increased risk for life-threatening age-related diseases.

The American Animal Hospital Association (AAHA) has proposed life stage guidelines for dogs that outline the different life stages of dogs:

Dog Life Stage

Description (Length of Time)


Birth to when growth stops (usually 6–9 months, varies with breed and size)

Young Adult

When growth stops when physical and social maturation stops, which is usually between 3–4 years of age

Mature Adult

When physical and social maturation stops until the last 25% of the estimated lifespan (breed and size dependent)


The last 25% of the dog’s lifespan through to the end of life

End of Life

Terminal stage (depends on specific ailments, conditions, or diseases)

When Is a Dog a Senior: How to Calculate Their Age


There’s a popular misconception that one dog year equals seven human years. This calculation is incorrect overall, as there are many more factors that go into determining a dog’s age than a simple calculation. 

But still, comparing a dog’s age to a human helps us understand the differences between how dogs age compared to humans, gives us further insight into basically when our dogs should hit certain age-related milestones, and helps explain age-related conditions. The “one dog year is equal to seven human years” calculation has likely stuck around because it’s easy for the average person to estimate a dog’s age.

Of course, a dog’s actual age can vary widely from dog to dog. But size is one of the largest (pun not intended) factors that affect a dog’s age. 

The American Kennel Club has provided a generalized chart that takes into consideration a dog’s size when determining its age that people can use to estimate the answer to the question, “when is a dog considered a senior?”



Signs of Old Age in Dogs

When a dog starts to get older, they can start exhibiting different physical and mental characteristics that are different from before, indicating that they have become or are becoming seniors. These signs are important to pay attention to because they could mean you must start making small adjustments to your dog’s exercise routine, diet, and more.

Behavioural Signs that Your Dog is Getting Old

Behavioural changes are one of the most common signs of old age in dogs. Sometimes these changes can result from Canine Cognitive Dysfunction Syndrome (CDS) or Canine Dementia. 

Veterinary professionals have established the acronym DISHA to help them classify the different types of behaviours that could be related to cognitive dysfunction in dogs:

  • Disorientation (staring blankly at a wall, getting stuck in corners and not being able to figure out where to go, and otherwise seeming like they don’t know their own environment)
  • Interactions with owners, other pets, and their environment are altered or “different” than normal, including aggression, increased attention-seeking, decreased social interaction, and irritability.
  • Sleep-wake cycle changes, like sleeping during the day and not being able to sleep at night
  • House soiling 
  • Activity changes, like overall lethargy and decreased interest in activities that once excite them (walks, playing catch, etc.)

In addition to these behavioural changes, other important indicators of senior dog cognitive dysfunction include:

  • Anxiety (fear of people, noises, and specific situations that didn’t bother them before, as well as excessive vocalization)
  • Learning difficulties or signs of memory loss (can’t perform tricks or respond to commands that they could before, and inability to learn new ones)

But it’s also important to realize that there can be other reasons why your dog is exhibiting the above behaviours besides “just getting old”. Pain from underlying medical conditions and diseases can also cause behavioural changes. While your dog might indeed be getting old for their size and breed, it’s important to seek a veterinarian's opinion to rule out any other explanations for behavioural changes before blaming them on age.

For example, taking longer to rise from lying down or sitting could indicate joint pain. While the joint pain could be because they are getting older, it doesn’t mean that there’s nothing you can do to help your pup. Incorporating joint supplements with glucosamine for dogs, such as TRI-ACTA H.A., is a good idea to help your aging pup’s joints.

TRI-ACTA H.A is recommended for seniors or dogs with ongoing joint problems because of the addition of hyaluronic acid (which is what the H.A. stands for). Aside from containing two types of glucosamine and chondroitin (helps protect and repair cartilage) and Methylsulfonylmethane (MSM, a natural anti-inflammatory), The hyaluronic acid in TRI-ACTA H.A. thickens the synovial fluid in your pup’s joints, allowing for easier and less painful movement. 

TRI-ACTA H.A. for Pets

Our maximum strength formula is optimally designed to accelerate the formation of cartilage, minimize inflammation, expedite the healing process, and improve joint conditions.


How to Care for a Dog When They Reach Senior Dog Age

When your dog gets older, you may have to change their diet, exercise, and more to accommodate them. 


When a dog reaches senior dog age, you may need to seek out the best senior dog food for their size and breed. Senior dog food is often specially formulated to help aging pups with their changing diet needs. These specific needs can include:

  • Dental issues—it’s not uncommon for senior dogs’ teeth to cause them problems with eating. This could be because of loose teeth, shrinking and bleeding gums, or general tooth pain. Dental problems should be addressed by a vet, which may result in your pup getting teeth removed, making it harder to bite kibble. Mixing water with kibble to soften it up or switching your dog to wet food are two possible solutions. 
  • Obesity—As dogs age, their bodies often need fewer calories because they are done growing. If a senior dog is overweight, it puts more stress and pressure on already degrading joints and can put them at a higher risk for heart-related diseases and arthritis. Most senior dog food formulas are lower in calories for this reason.
  • Diabetes—Another risk factor that comes with obesity and a high-fat diet is diabetes. Dogs suffering from diabetes can have various symptoms, from incontinence to poor vision. Feeding your dog a lower-calorie diet that matches their activity level is one way that you can help prevent diabetes. Also, ensure they have access to plenty of fresh, clean water at all times.
  • Arthritis—Many dog breeds (large and giant breeds especially) are at an increased risk of developing dog arthritis regardless of what diet you give them, but that doesn’t mean that you can’t help prevent it or at least make your dog more comfortable if they do develop the condition. Dog food for joint health includes glucosamine to help with arthritis-related joint issues, but it often isn’t a therapeutic amount (enough to actually make a difference). The best way to help prevent joint conditions later in life or help your dog currently suffering from joint problems is to incorporate a joint supplement into their diet. TRI-ACTA is the best joint supplement for dogs for preventing joint issues, while TRI-ACTA H.A. is recommended for dogs that are already experiencing joint health issues. 
  • Heart Disease—Some dogs can develop heart issues as they age. Like other issues we outlined in this article, heart disease can be caused by genetics, diet, breed, other health problems, and the environment. Feeding your dog a healthy diet that matches their life stage is important for prevention.
  • Kidney problems—when our pups reach senior dog age, it’s not uncommon for them to develop kidney issues. Problems affecting your dog’s kidneys can range from less function than before (but still fine) to complete organ failure. To keep your senior dog’s kidneys healthy, feed them a diet lower in phosphorus and high in moisture content. Making sure your dog is well-hydrated can go a long way in keeping their kidneys working properly as they age. 


Giving your senior dog supplements is a great way to ensure they have the necessary nutrients and support. Common types of supplements that you can give your senior dog include:

Senior Dog Supplement Type

How it Helps


Supplements for joint health provide additional support for repairing and strengthening the cartilage and fluid in your aging dog’s joints, aiding with ease of movement.


Supplements with probiotic and prebiotic fiber help support your senior dog’s immune system and ensure that their stomach has enough healthy bacteria for easy digestion and to ensure that they are able to absorb the nutrients from their diet.

Omega-3 fatty acids

Fish oil for dogs, one of the most common ways to provide omega-3 fatty acids, helps manage joint pain, improve your senior dog’s immune system, eyesight, brain activity, and more.


By reducing the effect of free radicals (bad molecules that attack your dog’s cells) in your dog’s body, antioxidants boost your pup’s immune system.

Medium chain triglyceride oils (MCT oils)

Recent research has shown that giving your dog MCT oils can slow CCD and dementia in senior dogs by increasing the total phospholipids in the brain (fats that protect brain cells), assist omega-3 fatty acids with accessing the blood-brain barrier, and increasing lactic acid and ketones in the blood (good alternative energy sources for the brain).


Every dog should get regular exercise. Of course, different dog breeds and personalities will have different exercise needs. For example, a Dalmatian will need more daily walks and playtime than an English Bulldog.

As your pup ages, you may have to adjust their regular exercise level. Your pup may seem less interested in playing as they age because chasing a ball or frisbee is more difficult, and instead prefer a short walk. Low-key exercise is great for senior pups because it’s not as hard on their joints.

Here are some ideas to help your senior pup get the daily exercise they need to stay healthy and moving:

  1. Walking—taking your dog for short walks around your neighbourhood is a great way for them to work their joints and muscles and stimulate their mind with new sights, sounds, and smells. 
  2. Taking them to the dog park—while your senior pup might not be too keen on chasing a ball or fetching a stick, the social interaction and encouragement to move around from other dogs can help them get much-needed exercise and keep their mind sharp.
  3. Swimming—because water has buoyancy, swimming takes the pressure off of your pup’s joints and allows them to move around with less pain. Hydrotherapy is commonly used for dogs with joint problems or recovering from surgery or trauma. 

Canine Enrichment

Like all animals, senior dogs need fun activities to keep them physically active and to keep their mind sharp. Canine enrichment can include a wide variety of activities, toys, and opportunities for socialization.



You’ll need to keep your pup’s age, energy level, and medical issues in mind when coming up with creative ideas to keep them active and engaged, but thankfully there are a lot of great ideas you can find online. 

  1. Snuffle mats (fabric mats with long ribbons or squares that hide treats and kibble that your dog needs to use their nose to find)
  2. Treat balls and toys that your dog has to use their brain to figure out how to extract the tasty food are great options for enrichment
  3. Doggy play dates with other dogs or animals that they know and like to play with are great for keeping your pup active and happy
  4. Chew and squeaky toys encourage your dog to play by themselves and help stop them from chewing your shoes or furniture
  5. Sandboxes are a great alternative to your yard for dogs that love to dig
  6. Taking your dog to different environments, such as walking in a different neighbourhood, gives them the chance to experience new smells, sights, and sounds

Home / Environment Setup

Older dogs aren’t as agile as they used to be, so you may have to modify your home to accommodate them. 

  • Dog stairs are a great option to help your senior pup get onto the couch, your pet, or their favourite chair rather than jumping up onto these areas, which could hurt their joints. 
  • Senior dogs have more trouble keeping their balance compared to younger dogs. Putting area rugs on slippery floors is a good idea so your dog has a lower chance of slipping and injuring themselves. 
  • If your dog has joint issues, giving them an orthopedic pet bed can help ease the pressure and stress off their joints as they rest. 

Proactively Preparing for Senior Dog Mobility


Did you know that nearly 20% of all dogs over a year old experience some form of arthritis? In addition, dog bodies slowly lose the ability to repair and replace degraded cartilage as they age. So you can imagine, then, that joint issues only become more prevalent in dogs as they age. 

Preparing for when your dog reaches senior age should be preventative and proactive.

  • Giving your dog joint supplements as early as possible is important to protect their joint health as they age. TRI-ACTA is a great dog joint supplement to give as a preventative measure. TRI-ACTA H.A. is recommended if your dog is already suffering from joint issues.
  • Being proactive by making small modifications to your home and your dog’s diet, exercise routine, and enrichment activities helps make the transition from adulthood to senior easier.

TRI-ACTA for Pets

A proactive approach for developing and younger adult pets to maintain optimal joint health mobility, minimize inflammation and fend off age-related ailments.



The answer to the question, “When is a dog considered a senior?” depends largely on your dog’s breed(s), size, and medical history. Determining a senior dog's age is more complex than simply adding seven years to each year your pup has been alive and assuming that’s their age. Because large breed dogs age faster than smaller breeds, they typically become seniors faster and benefit more from preventative and proactive care. 

Giving your dog joint supplements is important for maintaining joint health as they age. TRI-ACTA supplements are designated veterinary health products with independent batch testing to assure the quality of ingredients. 

Purchase TRI-ACTA or TRI-ACTA H.A. online, or find a retailer on our where to buy page.