The advice is always the same. Your dog is chewing the couch, so walk them more. Your dog is barking, so walk them more. Your dog is fat, so walk them more.
Sometimes that works. Often it does not, and the reason is that “under-exercised” is not one condition. It is two, and they need opposite fixes.
Deficit one is physical. The dog is losing muscle, gaining fat, and losing stamina. That dog needs conditioning: more movement, built gradually, plus strength.
Deficit two is mental. The dog is not tired, they are bored, and boredom in dogs looks almost exactly like excess energy. That dog can be marched five miles and come home just as frantic, because you moved their legs and left their brain switched on.
The signs below tell you which deficit you are dealing with. Get that wrong and you can walk a dog daily for a year while the actual problem sits there untouched.
The 7 signs
1. They are gaining weight
The most straightforward physical sign of insufficient activity is weight gain, along with subtler changes in muscle mass and endurance.
If your dog is getting heavier and slower, and a short game of fetch now leaves them panting and spent when it used to be a warm-up, they are deconditioned. Weight gain also compounds, because a heavier dog moves less, and a dog who moves less gets heavier.
2. Their appetite changed, in either direction
Some under-exercised dogs eat more, snacking out of boredom the way a bored human raids a fridge with nothing wrong with it.
But the opposite happens too, and it fools people. A dog can gain weight while eating less, because inactivity flattens their mood and slows their metabolism, and even a reduced intake can outstrip what their body is burning. A lethargic dog picking at dinner and still getting heavier is a very common presentation, and “cut the food” is the wrong first move.
Either direction is a signal. What matters is the change.
3. They are destroying things
Exercise is not only about the body. Going outside is about what the dog does with their brain: exploring, sniffing, and gathering information about the world. Take that away and frustration and anxiety fill the gap, and dogs soothe themselves with their mouths.
Destructive chewing, anxiety, and increased vocalizing, meaning barking, howling, and whining, are the emotional tab coming due. This is deficit two, almost every time. Shredded pillows are rarely a stamina problem.
4. They are pestering you constantly
Scratching or sitting at the door is the obvious version. The subtle version is attention-seeking that looks like misbehavior: whining, barking, and stealing things around the house that they do not even bother to destroy.
The sock is the classic. A dog takes a sock precisely because they know it is forbidden, and forbidden reliably produces a human who gets up and engages. That is not a dog with bad manners. That is a dog with nothing to do, running the only reliable game in the house.
Exercise is enrichment, but it is also bonding, and a needy dog is often a dog whose share of your attention has quietly shrunk.
5. They have gone flat
The counterintuitive one. Some dogs respond to under-exercise with zoomies and chaos. Others go the other way.
When a lack of activity continues long enough, it becomes normal to the dog. Their body adapts. They lose stamina, lose physical fitness, and become generally sedentary. They start to look lazy.
They are not lazy. They have given up, which is a bleaker thing to watch than a chewed cushion, and it is a great deal harder to reverse.
6. You can feel muscle disappearing
This is the sign almost nobody checks, and it is the most objective one available to you.
Under-exercised dogs lose muscle mass, especially over the hind end, which affects their mobility and raises their injury risk. Coat hides it. Hands do not.
Run your palms over both thighs and along the spine. Compare left to right, and compare to last month. A hind end that is going soft, or a spine whose bony ridge is becoming more prominent, is muscle loss in progress. It is also, importantly, the deficit that a sniffing walk will not fix. Muscle is built by working against resistance: hills, gentle inclines, sand, stairs taken slowly, and controlled sit-to-stand repetitions.
7. The health problems are arriving
Given enough time, inactivity stops being a behavior issue and becomes a medical one.
Carrying extra weight sets a dog up for the joint conditions nobody wants to treat: arthritis, and the kind of ligament tear that ends in surgery. It also drives diabetes, heart disease, and labored breathing, and that last one is genuinely dangerous in breeds whose airways are already compromised. Muscle loss makes each of those worse, because a weak dog hauling extra weight is a dog whose joints have nothing holding them steady.
The behavioral end is just as serious. Lack of exercise puts dogs at risk of behavior problems that are destructive and stressful, and those problems are one of the most common reasons dogs get rehomed.
Why “how much” has no answer
Every owner wants a number. There isn’t one.
Put a teacup Chihuahua and an Australian Shepherd on the same schedule and you will fail one of them badly. Two dogs of the same breed can also land far apart, depending on age, temperament, and how they live. Plenty of people buy a hiking partner and end up with a dog whose body was never going to do it.
Three variables set the number: what the breed was built for, what this particular animal is like, and what their day actually looks like. Your job is to work out what the dog in front of you requires, which is not the same as what you were hoping they would require.
That is why the signs above are more useful than any minutes-per-day chart. They read the dog rather than the label.
How to fix it without hurting them
The fastest way to turn an under-exercised dog into an injured dog is enthusiasm.
Go gradually. Genuinely gradually. A dog who has been sedentary for months cannot be returned to an active lifestyle in a weekend. Start with controlled leash walks and add five to ten minutes at a time. Set a pace where your dog is not panting heavily or stopping frequently to rest.
Do not go running with a sedentary dog. Suddenly taking an unconditioned dog for a run risks overheating and orthopedic injuries, including ligament tears, because their body is not built for that intensity yet.
Know what overheating looks like before you need to. The point of learning it is to call the session early, while your dog is still fine, rather than recognizing it once they are in trouble. Skip exercise altogether in extreme heat and during the worst hours of the day.
Be careful with newly adopted dogs. You have no idea what activity level they are used to from a previous home or a shelter, and a dog fresh out of a kennel is often thrilled to run, with a body that has not run in months. Their excitement outpaces their ability. Dogs, for all their gifts, are not reliable judges of what their own body can currently do.
“The rescue dogs who tear a cruciate ligament in the first month are almost always the ones whose new owner was proudest of them,” says Dr. Amara Solis. “The dog would run until they broke. It is on us to stop them at twenty minutes.”
The half of the fix people skip
While you build the body, feed the brain. That is not a consolation prize for rainy days; it is the treatment for deficit two, and it works faster than conditioning does.
Let them sniff. A twenty-minute walk where the dog chooses the route and stops constantly does more for a bored dog than a brisk forty-minute march where they are not allowed to investigate anything. Sniffing is the information-gathering that going outside is for.
Feed them out of a puzzle. Scatter kibble in the grass, roll it in a towel, or use a snuffle mat. A dog who works for dinner has done a job.
Train something, badly, for five minutes. Any new trick. The learning is the point, not the polish.
Hide things. Ten minutes of finding treats hidden around one room will settle a dog who was pacing.
The old line says a tired dog is a good dog. The correction is that the tiredness worth chasing usually is not in the legs at all, and the dog who gets it is calmer, easier to live with, and better off for reasons that have nothing to do with mileage.
What newer research adds
The muscle piece has gotten more attention lately, and it changes the timeline for when you should start worrying.
Sarcopenia, the age-related loss of muscle mass that is not caused by any underlying disease, appears to begin in dogs as early as seven or eight years old, even in dogs who are otherwise healthy. It cannot be cured, but it can be managed, and the management levers are adequate protein and consistent low-impact strength work: gentle incline walking, controlled strengthening exercises, and underwater treadmill work where it is available.
That reframes the “signs your dog needs more exercise” question for anyone with a middle-aged dog. At seven, the clock is already running. A dog who is under-exercised at that age is not only failing to build muscle; they are failing to defend the muscle they have against a process that has already started.
The practical upgrade is small. Add hills. Add a few controlled sit-to-stands before dinner. Walk on sand or grass instead of flat pavement when you have the option. And put your hands on your dog’s back end once a month, so that the day it starts going soft, you are the one who notices.
References
- Association for Pet Obesity Prevention. “2025 Pet Obesity and Nutrition Survey Results.” petobesityprevention.org/2025
- PetMD. “Sarcopenia in Dogs.” petmd.com/dog/condition/sarcopenia-in-dogs
- Freeman, L.M. “Cachexia and Sarcopenia: Emerging Syndromes of Importance in Dogs and Cats.” Journal of Veterinary Internal Medicine. onlinelibrary.wiley.com
- “The Value of Sniffing: A Scoping Review of Scent Activities for Canines.” Applied Animal Behaviour Science, 2024. sciencedirect.com/science/article/pii/S0168159124003332
- American Kennel Club Canine Health Foundation. “Exercise and Conditioning for Dogs.” akcchf.org
