Your dog isn’t immune to your bad days, which is something you probably already know by now. It’s a widely accepted idea that dogs mirror many of the behaviors and in many ways the demeanor of their beloved owner. Well, new research not only confirms that idea, but it also gives us an idea of just how a stressful day at the office (or anywhere, for that matter) affects your pup at home. In fact, it turns out the stress levels of a person can have a greater influence on a dog’s hormones than the canine’s own temperament.
What you might not have expected is just how researchers in Sweden went about pursuing their most recent findings. From a collection of 25 border collies, 33 shetland sheepdogs, and each canine’s female owner — all of which lived indoors with their owners — researchers at Linköping University in Sweden found that higher cortisol levels in human hair paralleled levels of the same hormone in dogs.
Cortisol, which is more plainly known as the “fight or flight” hormone, which creates a temporary increase in energy by trading off the instincts or hormones that are not needed for survival. The resulting hormonal imbalance is what we recognize as stress. It’s technically a normal and healthy process, from the moment an individual is faced with a stressor and cortisol is secreted to the increased heart rate, a resolution, and end to the experience with the stressor, and eventually a return to normal and natural hormone levels. However, regularly experiencing this process of confronting a stressor and the resulting hormonal response can and will wreak havoc on your entire body, including physical symptoms like fatigue and compromised immune responses.
Now imagine your dog experiencing that same roller coaster alongside you.
“This is the first time we’ve seen a long-term synchronization in stress levels between members of two different species,” said Lina Roth, an ethologist who led the work at Linköping University. “We haven’t seen this between humans and dogs before.”
The hair was cut in short strands close to the scalp in both the winter and summer of 2017 and 2018. While the link in the dog hormone levels in hair mirrored that of their owners, researchers found that it was higher in dogs during the winter months’ samples. Owners also completed surveys, which allowed them to report information on the dog’s temperament, offering a new set of controls in which researchers could account for expected results from a dog; a dog described as timid, fearful or anxious, was obviously expected to return greater cortisol levels in the test while dogs described as calm, confident or easygoing would presumably have lower cortisol levels. However, this wasn’t the case. Regardless of temperament, the dogs’ hair sample cortisol levels remained a mirror of their owners’.
The study went even further in measuring stress levels by comparing the cortisol levels of dogs enrolled in training and competitions for skills like obedience or agility and tricks. For these competing dogs, researchers found that the stress levels were even more closely mirrored between animal and owner. And according to Roth, it’s more than just woman and dog sharing the same home environment that causes this phenomenon, pointing out that they controlled for variables like dogs with an outdoor area to play in, owners working a different number of hours throughout the week, or even multiple dog homes and they found that there was no effect on the test dogs’ cortisol levels.
The main influence on each dog’s cortisol levels was simply the owners’ demeanor, as determined by self-reporting surveys in the study. The greatest factor, they found, was a neurotic owner, aka individuals who are more likely than average to be moody and to experience such feelings as anxiety, worry, fear, anger, frustration, envy, jealousy, guilt, depressed mood, and loneliness. Owners who scored highest on neuroticism had the dogs with the lowest levels of cortisol found in their hair. While this finding seems contrary to the study’s conclusion, Roth contested that these owners are more likely to seek attention and affection from their dog. The increased physical contact between the two could actually act as a comfort to the dog, therefore lowering their cortisol levels become a latent function. “Most dog owners are aware that their dogs pick up a lot of signals from them, even the unintentional ones, but it’s still beneficial to be together,” she said.
“Dogs are affected by their owners’ distress and respond with consoling behaviors,” said James Burkett at Emory University in Atlanta following a similar study in 2016 “We now know that dogs are also affected by their owners’ personalities and stress levels. While this may be common sense for dog owners, empirical research is still catching up to our intuitions about animal empathy.”
For humans, the presence of dogs is accepted as having health benefits for a number of reasons. Our hormones are regularly impacted positively by dogs, from hearts rates and blood pressure declining in their presence to getting more exercise and being more active simply by caring for one, to even having a more active social life when we own dogs. Looking into your dog’s eyes can increase levels of oxytocin, which we know as the love hormone, and dog owners are even known to live longer and healthier lives than non-dog owners. But of course, this new research has flipped the tables to study the possible negative effects our moods can have on our pups.
“What this paper seems to hint at is some of the underlying mechanisms behind why humans and dogs or wolves have been able to domesticate each other over thousands of years,” said University of Nebraska at Omaha developmental psychologist Jonathan Santo, who co-authored a 2015 study finding clear evidence of short-term emotional contagion between dogs and their owners. “We’re both social species, and once we became integrated into each other’s lives, it was to everyone’s advantage that dogs and humans would keep tabs on each other emotionally.”