Researchers at Linköping University in Sweden studied cortisol levels in 25 border collies and 33 Shetland sheepdogs, alongside the animals’ female owners.

Researchers believe they have found the first evidence that dogs mirror the amount of stress experienced by their owners.

Scientists in Sweden studied 25 border collies and 33 Shetland sheepdogs (13 females and 12 males), alongside the animals’ female owners.

Researchers at Linköping University (LiU) in Sweden quantified summer and winter levels of the stress hormone cortisol, which concentrates in the hair of both humans and dogs.

They found higher cortisol in human hair was matched by more of the hormone in the dog hair.

The work, “Long-term stress levels are synchronized in dogs and their owners”, has been published in Scientific Reports.

Synchronised

Ann-Sofie Sundman of the department of physics, chemistry and biology (IFM) at LiU, and principal author of the study said: “We found the levels of long-term cortisol in the dog and its owner were synchronised, such that owners with high cortisol levels have dogs with high cortisol levels, while owners with low cortisol levels have dogs with low levels.”

Subject dogs were regularly walked and all lived indoors with their owners. The dogs were grouped into either companion (15 Shetland sheepdogs and 11 border collies) or competing dogs (18 Shetland sheepdogs and 14 border collies) where competing dyads reported they actively trained and competed in either agility, obedience, or both disciplines.

The mean age of competing dogs was 4.7 ± 0.4 years, and 4.7 ± 0.7 years for pet dogs. The mean age of the owners was 46.1 ± 1.7 years.