October 14, 2022 3 min read

We all know that dogs are incredibly perceptive creatures, but did you know that they can actually sniff out your mood?  New research shows that dogs are able to reliably detect stress solely based on smell. In this blog post we will be covering the following:

  • Dogs keen sense of smell
  • New evidence around a dogs ability to sniff out stress
  • Implications of this research for service dogs

Dogs Keen Sense of Smell

It is a well-known fact that dogs have an incredibly accurate sense of smell, being able to detect odours at concentrations up to 100,000 times weaker than what humans can perceive. This keen sense of smell has made dogs valuable assistants in a variety of fields, including law enforcement, search and rescue, and environmental protection. In recent years, researchers have even begun to harness the power of dogs' noses in the fight against cancer.

New Evidence

It has also been well documented how dogs can be attuned to our emotions - but did you know that they can literally sniff out your mood? New research shows that dogs have the ability to distinguish between different human emotions by smell alone. 

In one particular study, published in September 2022, humans were asked to count backwards from 9000 in intervals of 17, causing high blood pressure in 27 people. Sweat and breath samples were then taken in the human's stress state and compared with samples taken when they were relaxed. 

Surprisingly, on average dogs were able to accurately tell which samples were taken 'while stressed' in 625 out of 720 trials.

Previously it was believed that dogs mainly used visual and auditory cues to detect their owners emotions. But this study proves that smell has a major part to play as well. 

It is still unclear what chemical the dogs pick up on when they smell stress, however some academics believe that it could be cortisol - a hormone caused by stress - or a mixture of different odours caused by stress including increased sweat. 

Implications for Emotional PTSD Support Dogs and Service Dogs

Service dogs have been used to support human psychological conditions for many years, but their popularity has grown in recent years. These specially trained dogs provide a wide range of services, from helping those with anxiety disorders to providing support for people with PTSD.

Service dogs can have a profound impact on the quality of life of their owners, providing companionship and emotional support. In some cases, they can also help to reduce symptoms of anxiety or PTSD. With the growing popularity of service dogs, there is an increasing demand for these specially trained animals. However, the number of service dogs available is not keeping pace with the demand, resulting in long waitlists for potential owners.

It is believed that humans give off these certain odours in the initial stages of stress and anxiety well before they give visual cues. With this new research, it is more than likely that training will be adjusted to help dogs detect 'stress scents,' to provide a greater quality of care. This means that service dogs can now have the potential to interrupt and intervene before it escalates. 


The study underlines the importance of man’s best friend and the valuable role they play in our lives. These findings could have a very positive impact on service dogs who are trained to help people with anxiety disorders or PTSD. Further research is needed to confirm these findings, but it is promising that dogs may be able to sense when their owners are about to have a panic attack and intervene accordingly.