Can dogs smell stress?
Dogs are often called "man's best friend" because of the powerful bond that can be established between a dog and its owner. This story has been going on since the dawn of time, as dog domestication dates back to prehistoric times. The capacities of their sense of smell, which are largely superior to those of humans, are used to detect bombs, drugs, certain pathologies (epileptic seizures, hypoglycemia, lung cancer, Covid-19, etc.) ... and even stress!
Indeed, an article published at the end of September 2022 studied the ability of a group of dogs to sense the stress of human volunteers. The volunteers were asked to perform a stressful task (mental arithmetic) and samples of breath and sweat were collected before and after. The dogs were then asked to determine which samples were obtained after the stressful task, and they were mixed with samples obtained before the task and a neutral sample. They had to report this by an alert behavior. After a total of 720 trials, the dogs had an surprisingly high success rate of 93.75%! This shows that dogs are able to detect molecules produced by humans in response to a stressful situation in breath and sweat.
This result is particularly interesting nowadays since dogs are more and more requested to soothe people suffering from anxiety or other psychiatric problems as well as in post-traumatic stress disorder. These animals were previously trained to respond to visual cues, but this may change in light of this study. Research on this question will have to be continued to determine precisely, for example, the nature of the molecules detected, for how long, and if this is also confirmed in the case of chronic stress...