The Science of Dog Sniffing: How It Reduces Stress and Improves Behavior

You rush your dog through their daily walk, tugging the leash whenever they pause to investigate an intriguing scent. “Come on, we need to get moving!” Sound familiar? What if, in your quest for exercise, you’re rushing your dog past one of the most important parts of the walk?

Welcome to the overlooked world of canine olfaction, where your dog’s nose isn’t just a cute feature but one of their primary ways of gathering information about the world. In my previous blog, Let Them Sniff, I introduced why sniffing matters so much to dogs. Now let’s look more closely at the research behind sniffing, nosework, and scent-based enrichment.

The research is a little more nuanced than simply saying “sniffing calms dogs.” Spontaneous sniffing on walks has been associated with decreases in dogs’ pulse, while nosework has been associated with a more positive judgment bias and scent-trained dogs have shown stronger inhibitory control in some cognitive tests. At the same time, not every form of scent work is physiologically calming. Scent searching can also be exciting and arousing.

That doesn’t make sniffing any less valuable. It just gives us a more accurate understanding of why giving dogs opportunities to use their noses is so important.

1. Sniffing Can Help Dogs Regulate and Gather Information

Your dog’s nose is constantly collecting information. Who has been here? How recently? Was it another dog, a wild animal, or a person? What direction did they travel? A walk that looks uneventful to us can be incredibly information-rich to a dog.

One field study by Cristina and Aurélien Budzinski followed 61 dogs during walks on different leash lengths and off leash while monitoring pulse. Dogs spent considerably more time sniffing when they had greater freedom to move, and sniffing was associated with decreases in pulse even while the dogs were still moving (Budzinski & Budzinski, At the Heart of the Walk).

That makes spontaneous sniffing particularly interesting when we think about regulation. It doesn’t mean that every time a dog puts their nose down their nervous system is shifting into relaxation, but it does support something trainers and dog owners often observe: allowing dogs time to stop, investigate, and gather information can change how they move through the environment.

Rather than treating every pause to sniff as an interruption to the walk, try thinking of sniffing as part of the walk.

2. Nosework Provides Valuable Mental Enrichment

Sniffing is one of the most natural ways dogs interact with their environment, and structured nosework gives them an opportunity to use that ability intentionally.

A 2019 study published in Applied Animal Behaviour Science compared dogs who practiced nosework with dogs who practiced heelwork for two weeks. Dogs in the nosework group subsequently showed a more positive judgment bias on a cognitive test. In other words, they approached an ambiguous situation more optimistically after the nosework intervention (Duranton & Horowitz, 2019).

That’s an interesting welfare finding. It suggests that giving dogs opportunities to use their noses, make choices, and independently solve problems may have benefits beyond simply keeping them occupied.

For most pet dogs, you don’t need formal scent-detection training to provide those opportunities. Searching for food, finding hidden treats, exploring new environments, and simple nosework games can all give your dog a chance to use their strongest sensory system.

3. Scent Work May Support Cognitive Skills

There’s also some interesting research looking at dogs who regularly participate in scent work.

A 2024 study in Animals compared pet dogs whose primary training disciplines included scent work, agility, and obedience. Dogs trained primarily in scent work showed stronger inhibitory control across two cognitive tasks than dogs trained primarily in agility (Mellor et al., 2024).

That finding is interesting, but I wouldn’t take it to mean that doing nosework automatically teaches a reactive dog to stay calm. The study compared dogs with different training histories, so we can’t assume scent work itself caused the difference.

What it does add to the larger picture is that scent work asks dogs to concentrate, persist, ignore irrelevant information, and independently solve a problem. Those are useful skills, and scent-based activities can be a great part of a broader enrichment and behavior plan.

I use scent activities frequently with my own clients, including dogs dealing with reactivity and overexcitement. Sometimes I’m using them for enrichment. Sometimes I want to give the dog something constructive to do with their attention. Sometimes I simply want to give a dog more opportunities to behave like a dog.

4. Sniffing Can Be Useful After a Difficult Moment, But It Isn’t Automatically Calming

This is where I’d update some of the advice I’ve given in the past.

It’s very common in dog training to say that sniffing “lowers arousal” or that scatter feeding automatically activates the parasympathetic nervous system. The evidence doesn’t support making that statement quite so broadly.

Spontaneous sniffing on walks has been associated with decreases in pulse. But structured scent searching can also be exciting. A 2026 study that measured dogs’ heart rate and heart-rate variability during scent work found that heart rate was highest during goal-directed searching. The dogs didn’t display stress-related behaviors during the search, which is an important reminder that arousal and distress aren’t the same thing (Fountain et al., 2026).

That distinction matters.

If my dog has just reacted to something on a walk, I may still toss food into the grass or move them into an area where they can sniff. A food scatter can help interrupt fixation, change what the dog is doing, encourage movement away from the trigger, and give them a simple task. Allowing the dog to investigate an area can also give them information about the environment.

I just wouldn’t describe the mechanism as “sniffing automatically calms the nervous system.”

The same caution applies to research on olfactory enrichment. One frequently cited shelter study found that dogs exposed to lavender and chamomile spent more time resting and less time moving and vocalizing. That tells us certain odors can affect behavior, but the study involved passive scent exposure. It wasn’t a study of dogs actively sniffing, searching for food, or doing nosework, and it didn’t measure cortisol (Graham, Wells & Hepper, 2005).

There are still plenty of good reasons to use sniffing after a difficult event. We just don’t need to claim more than the evidence shows.

5. How to Encourage Sniffing in Your Dog’s Daily Routine

There are lots of easy ways to make sniffing a bigger part of your dog’s life:

• Take your dog somewhere new. New environments give dogs new scent information to investigate.

• Use a long line or drag line. More freedom of movement can give dogs more opportunities to choose where and when to sniff. Learn more about using a dog drag line here.

• Scatter food in the grass. Your dog gets to search for individual pieces rather than eating everything from a bowl. I think of this as enrichment and a useful search activity rather than assuming the search itself is automatically calming. You can see a video demonstration here.

• Use puzzle toys and snuffle mats. These create easy indoor opportunities to forage and search.

• Try ACE Free Work. This gives dogs opportunities to investigate different sensory experiences at their own pace.

• Teach nosework games. I use scent-based exercises with many of my coaching clients because they’re an easy way to add choice, problem-solving, and enrichment.

You don’t need to turn every walk into formal nosework. Sometimes the easiest enrichment is simply giving your dog enough time to investigate the smells they already care about.

Sniffing is much more than something dogs do when they’re distracted on a walk. It’s how they explore, gather information, forage, solve problems, and interact with their environment.

The science also gives us good reasons to provide more olfactory opportunities.

Nosework has been associated with a more positive judgment bias, scent-trained dogs have shown interesting differences in inhibitory control, and spontaneous sniffing during walks has been associated with decreases in pulse.

None of that requires us to say that all sniffing is calming.

Whether you’re working with a reactive dog, adding enrichment to your daily routine, or simply trying to give your dog a more fulfilling walk, letting them use their nose is one of the easiest things you can do to give them more choice and a richer experience.

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Give Your Dog More Opportunities to Use Their Nose

If you’re trying to figure out how enrichment, scent work, and behavior modification fit together for your particular dog, this is the kind of work I do in The Dog Lab. I build training plans around the dog in front of me rather than assuming one activity has the same effect on every dog.

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