I’m sure I’ve mentioned this before that every time we travelled our dog got visibly disturbed and fell ill -every single time. So, when the pandemic hit, and we stopped travelling I silently felt relieved. Because I never doubted that my dog can smell stress and no travel means no stress. What’s more, now a study has proved that dogs can sense stress.

The physiological processes associated with an acute psychological stress response produce changes in human breath and sweat that dogs can detect with an accuracy of 93.75%, indicates a new study.

What the study says

Researchers collected samples of breath and sweat from non-smokers who had not recently eaten or drank. Samples were collected before and after a stress-inducing task.

Samples from 36 participants who reported an increase in stress because of the task and experienced an increase in heart rate and blood pressure during the task were shown to trained dogs within three hours of being collected. At testing, four trained dogs were asked to find the participant’s stress sample (taken at the end of the task). The same person’s relaxed sample (taken only minutes before, prior to the task starting) was also in the sample line-up.

Overall, the dogs could detect and perform their alert behaviour on the sample taken during stress in 675 out of 720 trials, or 93.75% of the time. The first time they were exposed to a participant’s stressed and relaxed samples, the dogs correctly alerted to the stress sample 94.44% of the time.

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“This study demonstrates that dogs can discriminate between the breath and sweat taken from humans before and after a stress-inducing task. This finding tells us that an acute, negative, psychological stress response alters the odour profile of our breath/sweat, and that dogs are able to detect this change in odour,” the authors added.