We’ve all heard it: “Take a deep breath.” It’s simple advice that’s easy to ignore. Yet that breath is powerful. Slow, deliberate breathing nudges the parasympathetic nervous system, steadies heart rate variability (HRV), and clears the mind—buying you a beat to choose your next move (Laborde et al., 2022). Our dogs have their own version of this reset button: sniffing.

The Science of Sniffing

When a dog sniffs, it isn’t just curiosity—it’s physiology. Purposeful olfactory activity can help shift the autonomic nervous system toward a calmer state and support emotional regulation (Duranton & Horowitz, 2019; Rooney et al., 2016). After a stimulating event, cortisol (a primary stress hormone) does not rise or fall instantly; in dogs, salivary cortisol typically peaks about 10–20 minutes after a stressor and then gradually returns toward baseline (Beerda et al., 1998; Svobodová et al., 2014). Guiding a dog into scent-focused activities during this window helps the body and brain de-escalate as stress hormones naturally taper.

Why Sniffing Helps

  • Activates the “SEEKING” system. Sniffing taps a conserved motivational circuit associated with exploratory drive and dopamine (Panksepp, 1998), which is consistent with findings that nose work biases dogs toward more optimistic judgments (Duranton & Horowitz, 2019).
  • Supports emotional regulation. Olfaction is central to how dogs make sense of their world; structured scent work is linked with more positive affect and better welfare indicators (Duranton & Horowitz, 2019; Rooney et al., 2016).
  • Aids recovery. After arousal, directing an overexcited or reactive dog to a calm “sniff spot” or a simple scent task can help them settle while the physiological stress response recedes (Beerda et al., 1998).

Physiological signs of calm. Sensory-enrichment studies show olfactory engagement can influence vagal activity/HRV in dogs—markers associated with relaxation (Amaya et al., 2020).

Not All Sniffing Is Relaxing

For some dogs—especially high-drive gundogs—sniffing can tip into overstimulation if it becomes uncontrolled “self-employment.” Excessive sensory input or intense wildlife scents can hijack focus; without guidance, instincts may outrun handler engagement. Using structure and context keeps sniffing calming rather than chaotic (Rooney et al., 2016).

Make Sniffing Work For Your Dog

  • Guided scent games. Try scatter feeding, simple “find it” searches, or short nose work setups to channel curiosity productively (Duranton & Horowitz, 2019).
  • Controlled exploration. Use a long line in rich-scent areas so your dog can investigate safely without spiralling up (Rooney et al., 2016).
  • Purposeful engagement. Short searching/retrieving games satisfy drive while keeping arousal manageable (Rooney et al., 2016).
  • Reinforce calm. Mark and reward relaxed focus during sniffing; you’re teaching that calm earns access to what they love.

The Shared Lesson

For both humans and dogs, calm is a physiological shift that takes a little time. Your breath; their sniff. Two versions of the same truth: when stress surges, a simple, well-timed act can bring us back to balance (Laborde et al., 2022; Duranton & Horowitz, 2019).

References

Amaya, V., Paterson, M. B., Phillips, C. J. C., & McGreevy, P. D. (2020). Effects of olfactory and auditory enrichment on heart rate variability in shelter dogs. Animals, 10(4), 581. https://doi.org/10.3390/ani10040581

Beerda, B., Schilder, M. B. H., van Hooff, J. A. R. A. M., de Vries, H. W., & Mol, J. A. (1998). Behavioural, saliva cortisol and heart rate responses to different types of stimuli in dogs. Applied Animal Behaviour Science, 58(3–4), 365–381. https://doi.org/10.1016/S0168- 1591(97)00145-7

Duranton, C., & Horowitz, A. (2019). Let me sniff! Nose work induces positive judgment bias in pet dogs. Applied Animal Behaviour Science, 211, 61–66. https://doi.org/10.1016/j.applanim.2018.12.009

Horowitz, A. (2017). Smelling themselves: Dogs investigate their own odours longer when modified in an “olfactory mirror” test. Behavioural Processes, 143, 17–24. https://doi.org/10.1016/j.beproc.2017.08.001

Laborde, S., Mosley, E., & Mertgen, A. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and meta-analysis. Neuroscience & Biobehavioural Reviews, 138, 104711. https://doi.org/10.1016/j.neubiorev.2022.104711

Panksepp, J. (1998). Affective neuroscience: The foundations of human and animal emotions. Oxford University Press.

Pedretti, G., Canori, C., Marshall-Pescini, S., Palme, R., Pelosi, A., & Valsecchi, P. (2022). Audience effect on domestic dogs’ behavioural displays and facial expressions. Scientific Reports, 12, 9747. https://doi.org/10.1038/s41598-022-13566-7

Rooney, N. J., Clark, C. C. A., & Casey, R. A. (2016). Minimising fear and anxiety in working dogs: A review. Journal of Veterinary Behaviour, 16, 53–64. https://doi.org/10.1016/j.jveb.2016.11.001

Svobodová, I., Chaloupková, H., Končel, R., Bartoš, L., & Hradecká, L. (2014). Cortisol and secretory immunoglobulin A response to stress in German Shepherd dogs. PLOS ONE, 9(3), e90820. https://doi.org/10.1371/journal.pone.0090820

Wilson, C., Mitchell, A., & Hall, S. S. (2022). Dogs can discriminate between human baseline and psychological stress condition odours. PLOS ONE, 17(9),e0274143. https://doi.org/10.1371/journal.pone.0274143

Parr-Cortés, Z., et al. (2024). The odour of an unfamiliar stressed or relaxed person affects dogs’ responses to a cognitive bias test. Scientific Reports, 14, 15843. https://doi.org/10.1038/s41598-024-66147-1