Dogs can smell stress

Our body smells when it is stressed and dogs can sniff it.

When we humans are stressed our body experiences many phycological changes. It releases many chemicals into our bloodstream. These chemicals show the stress in our bodies. 

We are aware of the qualities of dogs. Dogs are super-sniffers. But the new research reveals how dogs can identify whether humans are in stressful situations by smelling the odors. Besides giving us a deeper understanding of the relationship between dogs and their owners, this research can be used for the improvement of training in dogs that are involved in support for anxiety, panic attacks, and post-traumatic stress disorder (PTSD).

"The findings show that we, as humans, produce different smells through our sweat and breath when we are stressed, and dogs can tell this apart from our smell when relaxed – even if it is someone they do not know," says animal behavior researcher Clara Wilson from Queen's University Belfast in the UK. "The research highlights that dogs do not need visual or audio cues to pick up on human stress".

This study involved four dogs -  Treo, Fingal, Soot, and Winnie – and 36 people. There were a total of 720 smell tests carried out. The human participants were asked to complete a difficult math problem and self-report their stress levels at the same time. The dogs were trained to alert researchers to the correct sample Due to the difficult problem, the heart rate, and blood pressure were increased. Then the samples of sweat and breath were taken. 

The dogs were then presented with these samples to see if the canines could alert researchers to the stress samples. The relaxed samples were taken four minutes before the task began. In 94 percent of the 720 trials, the dogs were able to correctly alert researchers to the stressed sample. It seems that dogs can pick up the chemical changes introduced due to stress. 

One of the dog who actively participated in the study was a two-year-old Cocker Spaniel named Treo. Helen Parks, Treo's owner says "The study made us more aware of a dog's ability to use their nose to 'see' the world. We believe this study really developed Treo's ability to sense a change in emotion at home".

"This is the first study of its kind, and it provides evidence that dogs can smell stress from breath and sweat alone, which could be useful when training service dogs and therapy dogs," says Wilson. "It also helps to shed more light on the human-dog relationship and adds to our understanding of how dogs may interpret and interact with human psychological states."

Earlier studies have proved that dogs can detect our emotions of happiness and fear through the smell we give off by sniffing. This research ties in with the earlier research by connecting more data to it. Also, we can add this to the long list of subtle shifts in humans that dogs can smell, even when visible signs aren't present. For example, we can remember that canines have previously been used to sniff out COVID-19 infections.