In this article
Picture your dog flopped on the floor after a long walk, legs splayed, eyes half-closed, utterly spent. It is a satisfying sight, and it is where the old saying comes from: a tired dog is a good dog. But tiredness is an odd thing to aim for, and the research points somewhere gentler.
What a dog gets from a nose-led hour is less exhaustion than contentment. Here is what the science says about sniffing and chewing, how to fold them and a few thinking games into an ordinary week, and the signs that a dog may have had enough.
What a sniff tells your dog
Start with the nose, because it explains the rest. Proportionally, a dog gives about thirty times more of its brain to the olfactory bulb than we do, according to one review6. You may have read that smell takes up forty per cent of a dog's brain. It does not. The same review does give a figure of 43%, but that is how much of a hemisphere's diameter the bulb spans, which is a different measure from its share of the volume6.
Dogs read a great deal from a scent, and they sniff longer at the smells that interest them most, according to a review of canine olfaction7. The same review calls a marked tree or streetlamp a scent message, full of information about the dog who left it7. So a dog at a lamppost may well be reading the news. Give it the time to read it.
Is scent work calming? Not quite
Which brings us to the sniffari, the walk where your dog sets the pace and the route and stops at every lamppost for as long as it likes. You will often read that sniffing is calming: that it lowers the pulse and winds a dog down. A 2026 study measured what happens during trained scent work, which is not quite the same thing. Its authors note both that claim and that professional trainers, in an earlier survey, saw scent work as something that tires a dog out and lowers arousal1.
An Australian team fitted 21 dogs experienced in scent work with heart monitors. Each dog spent five minutes on the lead searching for hidden scents, with a food reward for each find, and five minutes walking around an empty room, with ten-minute waits before, between and after1. Heart rate rose during both activities and was highest during the search, heart rate variability showed no difference between them, and afterwards the dogs' hearts settled at the same rate whichever they had done1.
Their conclusion is the opposite of the folklore: scent work looks like more arousal, not less. The reassuring half is that the searching dogs held their tails higher and showed no sign of fear or distress1. A trained search is not a sniffari, though. The same paper points to another study in which dogs' heart rates were higher while they searched for food than while they sniffed the ground of their own accord1, so the free sniffing of a slow, nose-led walk may be the gentler of the two.
What sniffing may do instead
So if scent work does not sedate a dog, what does it do? It may change how they feel about the world. In a 2019 study, pet dogs spent two weeks doing daily nosework while a control group practised heelwork. Both groups were tested before and after on a standard optimism measure: an ambiguous cue that a hopeful dog trots towards and a pessimistic one hangs back from2.
The nosework dogs approached the ambiguous cue significantly faster after their fortnight, and the heelwork dogs did not change2. More time using their noses, the researchers concluded, made the dogs more optimistic2. It is one study, though: a 2026 comparison of scent-work and obedience classes found no such advantage, although owners rated their scent-work dogs' quality of life higher1. Not more tired, then. Perhaps more optimistic, which is the better thing to hand a dog anyway.
Easy sniffing games, and a word on chewing
Once you stop chasing exhaustion, a whole menu opens up, and most of it fits in your living room or garden. Only the snuffle mat needs any kit, and each idea turns food your dog would eat anyway into something to do.
| Game | How it works | When it helps |
|---|---|---|
| Scatter feeding | Toss the meal across the lawn or a towel so the bowl becomes a search | Any day, at mealtime |
| Snuffle mat | Hide kibble in the fabric strips for foraging indoors | Wet days and quiet evenings |
| Find it | Ask your dog to wait, hide a treat behind a chair leg, then send them to search | Building focus at home |
| A new trick | Five focused minutes of something new, with plenty of rewards | Busy minds |
However often you see it claimed, we could find no study showing that twenty minutes of sniffing tires a dog more than a run, and the heart-rate study saw no sign of dogs settling any faster after a search than after a plain walk1. Enjoy these games for what they are: absorbing, and perhaps good for a dog's outlook too.
A word on chewing
Chewing deserves a place too, with a clear label on it. A 2025 review of chewing in dogs argues that it helps dogs manage stress and arousal, but much of the evidence behind that comes from studies of people and rodents8. The one dog experiment it reports on chewing and stress is worth knowing: fearful Labradors did better on a spatial memory test straight after five minutes of chewing, while the non-fearful dogs did not improve, and dogs that bit down harder did better in a maze8.
The review also says the amount of chewing a dog needs for the best welfare remains unknown8. So offer a chew that is safe, long-lasting and sized for your dog, and enjoy the quiet it brings, without expecting it to work like a sedative.
Signs your dog has had too much
The aim throughout is a satisfied dog rather than a flattened one, and too much of a good thing is still too much. The signs worth noticing are the ordinary ones.
Signs to watch for
- A shorter fuse than usual
- Leaving food they would normally gobble
- Zoomies that will not settle
- Restless, broken sleep
- No off switch when the house goes quiet
Nobody has tested that list, and every sign on it can also mean pain, illness or plain boredom. If your dog is off their food, seems sore, or their behaviour has changed suddenly, ask your vet first. Otherwise, note what you saw and when, try a few quieter days, and tell your vet if the pattern keeps coming back.
Puppies, older dogs and flat faces
Big, fast-growing puppies
Age and breed shift the picture. For big, fast-growing puppies, one large study gives a steer for the first three months. Norwegian researchers followed 501 puppies from 103 litters of Newfoundlands, Labradors, Leonbergers and Irish Wolfhounds and X-rayed their hips at 12 or 18 months4.
Puppies using stairs in their first three months were more likely to develop hip dysplasia, while puppies getting off-lead exercise in that window were less likely to4. The researchers recommended no stairs for puppies up to three months old, and outdoor exercise on soft ground in moderately rough terrain4.
For a big, fast-growing puppy
Do
Don’t
- Cut out off-lead play in those early months to protect their hips4
- Treat one study as a rule for every breed; it followed four large breeds
Older dogs
Many dogs need a little less exercise in their senior years3, and the slow, sniffy kind of walk asks less of stiff joints than a long hike does. It is a lovely way to keep an older dog's day interesting when long outings are behind them.
Breeds
Breed matters too: the PDSA says some breeds need at least one to two hours of exercise a day and working breeds significantly more3, which will not surprise anyone who lives with a collie. Noses are less clear-cut. One olfaction review reports that breeds selected for scent work do show a sharper sense of smell, then notes a view that breed differences in scenting ability may not exist at all7.
Flat-faced dogs
Flat faces bring a caution with numbers behind it: airway disease. In a small study of 36 dogs given a six-minute walk test, flat-faced dogs had higher heart rates than dogs with average-length muzzles straight after the walk and five minutes later. A quarter of an hour on, only the dogs with brachycephalic obstructive airway syndrome were still raised5.
Thermal imaging also showed the dogs with the airway syndrome running hotter around the nose and muzzle at every point, compared with average-muzzled dogs5. The authors think these dogs may also take longer to recover than healthy flat-faced dogs, but it was a small pilot study, and the heart rates of those two groups never differed significantly5. A pug or bulldog who snorts or snores and tires quickly cannot cool down well by panting5, so keep their activity short, cool and measured, and get a vet's ear on that breathing.
A week that suits most dogs
Mix the two kinds of walk across the week instead of picking a side. Most dogs need at least one or two walks a day: a brisk one burns off energy, and a slow, meandering, sniffy one is great for their mental health, as the PDSA puts it3. Weave scent and thinking games into ordinary moments and keep the easy days easy. If you are unsure what suits your own dog, especially one with a health condition or a joint problem, ask your vet.
The flop on the floor was never the goal. The goal is the dog who is glad to be here, nose full of news. If that dog then sighs and falls asleep across your feet, take it as a bonus.
Sources and further reading8 sources
The small numbers in the article link to the source behind each fact. Sources open on their own websites.
- Heart rate variability and behaviour in dogs during and after scent work
- Let me sniff! Nosework induces positive judgment bias in pet dogs
- Exercising your dog
- Housing- and exercise-related risk factors associated with the development of hip dysplasia as determined by radiographic evaluation…
- Evaluation of infrared thermography and 6-minute walk tests to assess airflow limitation, impaired thermoregulation…
- The Olfactory Bulb in Companion Animals—Anatomy, Physiology, and Clinical Importance
- Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications
- Functional significance and welfare implications of chewing in dogs (Canis familiaris)