Can Dogs Smell Human Stress? New Research Says Yes*

If you’ve ever felt like your dog “just knows” when you’re stressed, science is catching up with you. A 2022 study from Queen’s University Belfast tested whether dogs can tell the difference between a person’s normal scent and their scent during psychological stress—and the results were striking.

What the researchers did (in simple terms)

• Who: 36 adults provided scent samples; 4 trained pet dogs did the sniffing.

• How they created stress: Participants did a short, challenging mental arithmetic task (counting backwards in 17s under pressure).

• What was collected: Each person gave two samples—one before the task (baseline) and one right after (stress). Samples combined breath and sweat (gauze swabbed on the back of the neck + exhaled breath into a vial).

• Double-checking stress: Researchers confirmed stress with self-reports and, for most participants, physiological measures (heart rate and blood pressure).

• How dogs were tested: Using a careful double-blind setup, dogs first learned which jar held the “stress” sample. Then they had to choose between three options: the stress sample, the same person’s baseline sample, or a blank.

What they found

• The dogs correctly picked the stress sample 93.75% of the time (individual dogs ranged ~90–97%).

• Dogs often nailed it on the very first try in each session.

• Controls ruled out “cheating” by sight or leftover smells on the equipment.

Bottom line: When people experience acute psychological stress, their breath/sweat odor profile changes in ways that dogs can reliably detect.

Why this matters for everyday dog guardians

• Your dog’s sense of smell isn’t just for food crumbs and squirrel trails, it’s tuned to your internal state.

• When you’re stressed, your dog may be responding to actual chemical changes on top of your body language and voice.

Practical takeaways

For pet parents

• Acknowledge the cue: If your dog gets clingy or alert when you’re anxious, they may be picking up your stress scent. Gently reward calm check-ins (treats, quiet praise) so sniffing you out becomes a positive, low-arousal behavior.

• Model calm: Pair your self-regulation (slow exhale, soft voice, relaxed posture) with a simple cue your dog knows (mat settle, nose target). Over time, your dog associates your calming routine with safety.

• Create a routine: Teach a “go to place” or relax on a mat behavior. When you feel stress rising, cue the behavior and reward relaxation. It helps both of you.

For trainers & behavior pros

• Consider adding scent-informed protocols to support clients with anxiety or panic.

• Train “check-in then settle” sequences: dog notices owner shift → gentle nudge/target → reinforce quiet settle (on a mat or by the owner’s side).

For service-dog applications

• This research supports training PTSD/anxiety service dogs using owner-specific stress samples (baseline vs. stress) to strengthen alert and interruption tasks—while always balancing welfare and arousal management.

What this study doesn’t claim

• It doesn’t say dogs can identify every emotion by smell, or that smell is the only cue they use. Dogs read a whole picture, odor + body language + voice.

• It looked at short-term (acute) stress, not long-term chronic stress patterns.

• Only four dogs were tested (common in scent research due to intensive training), so results show what trained dogs can do under controlled conditions.

How to support your dog when you’re stressed

1. Name it and normalize it: “I’m stressed; thanks for checking on me.”

2. Slow everything down: breathe, soften your voice, move deliberately.

3. Cue a familiar calm behavior: mat settle, chin rest, hand target.

4. Reinforce quietly: small treats, gentle strokes in a place your dog enjoys.

5. Build a plan for you: short walk, sniffari, puzzle feeder—channel your dog’s empathy into structured calm.

Human Dog Harmony’s take

Our mission is to deepen the bond between people and dogs with science-based, compassionate training. Studies like this remind us that dogs are not just watching us, they’re smelling our inner world. When we prepare our dogs with clear, positive routines, and prepare ourselves with simple regulation tools, we turn a challenging moment into a connection moment.

Want help building a “check-in → settle” routine tailored to you and your dog? I can draft a step-by-step plan you can start this week.

*Source: Wilson, C., Campbell, K., Petzel, Z., & Reeve, C. (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