Verified by 
I remember the first few times that I heard someone say something on the order of "I really don't have to walk my dog. She is small and gets enough exercise running around the house, and all that I have to do is to let her out into the backyard to relieve herself." Back then I thought that not walking a pet dog was odd and unique behavior, and, after interacting with some of those walk-deprived dogs I wondered if that lack of exercise accounted for some of the "twitchy" behaviors that I observed — you know the sort of behaviors which lead you to believe that a dog is very submissive, poorly socialized or experiencing some kind of stress. However, those were casual observations, and my speculations were not based on any research.
Being the kind of scientist that I am, I began to search the research literature and found owners that don't walk their dogs are not rare at all. Various surveys indicate that around 40% of dog owners seldom or never walk their dogs. A few studies which looked at the effects of this situation tended to concentrate on the fact that dogs that were not regularly walked were more likely to become obese. However, of the studies that I found none mentioned behavioral effects.
Science tends to proceed in a fairly erratic way, and sometimes the answers to questions that have been bothering us emerge as unexpected findings from studies which have been directed toward a completely different problem. Thus it was that while I was looking for new information on stress in dogs I was surprised to find some data about the effects of dog walking on canine behavior in a recent study published in the journal Physiology and Behavior*. A research team headed by Simona Cafazzo at the Department of Neuroscience, University of Parma, Italy was looking at the long-term impact of an Italian national animal welfare law passed in 1991. This law introduced a "no-kill" policy for dog shelters except for dogs that have an incurable illness or have proved to be dangerous. Since many dogs placed in shelters remain unadopted, the team was particularly interested in the welfare of the dogs that ended up becoming long-term residents in these kennels. What caught my eye was the fact that this study was looking at a measure of long-term stress and trying to determine which living conditions might increase or decrease it.
The subjects of this study were 97 healthy mixed breed dogs between the age of 2 and 7 years that had been living in the shelter for 2 to 3 years. To get a measure of the behavior of the dogs each was observed for 5 hours (except for dogs that were kept in a group living shelter who were videotaped and then later had their behaviors scored). The researchers were looking at a broad spectrum of behaviors that tend to be associated with high levels of stress (such as body shaking, muzzle licking, pacing in circles, licking or biting kennel cage bars, self-mutilation and so forth) as well as behaviors that indicate low levels of stress (tail wagging, seeking physical contact with other dogs and so forth). In addition the researchers took a blood sample from each dog. What is interesting about the way in which the investigators analyzed the blood was that they not only looked at the concentration of the stress related hormone cortisol (which can change quite quickly depending upon short term stressors) but they also looked at the concentration of white blood cells (leukocytes) which are a measure of longer-term stress. It is well known that chronic stress can cause tissue damage which may ultimately lead to death. The body responds to such stressors with an increase in the number of white blood cells, which in turn is also associated with the production of antioxidants to help combat the damage. So this type of analysis can show the presence of long-term stress states and the body's attempts to compensate for it.
The first thing the researchers did was to simply check to see if their blood measures were related to the stress related behaviors that they had been observing in the dogs. In fact this turned out to be the case, and the dogs whose blood samples indicated that they had a higher level of antioxidant capacity were found to show fewer stress-related anxious and disturbed behaviors. Overall the behavior of these dogs were more likely to be more relaxed and they showed a higher frequency of friendly, sociable, behavior toward other dogs.
The researchers then looked at the living conditions and personal characteristics of the dogs to see which best predicted the blood markers associated with lower stress levels. They looked at a lot of things, including the sex of the dog, the size of the kennel cage, whether dogs were kept alone in their kennels, whether the dogs were neutered, as well as a variety of other factors. None of these had any significant effect on the indicators of stress in the blood except for one thing — whether the dog had the opportunity to leave its cage and go out on a walk. This one factor, the daily experience of being walked by a volunteer at the shelter, seemed to make all of the difference. Dogs that were walked on a regular basis showed less evidence of stress and anxiety, fewer stereotyped and dysfunctional behaviors, were more companionable and relaxed. This conclusion was confirmed by the analysis of their blood samples.
This finding was a bolt out of the blue, since the opportunity to be walked routinely was just one of many variables that the researchers were looking at. Remember that they had set out to assess the welfare of dogs that were long-term residents in animal shelters because of the national law preventing euthanasia of stray and surrendered dogs. The frequency of dog walks was certainly not a variable that the researchers had singled out as a special focus. Because this was an unanticipated result there might be other factors that were not controlled for in advance. For example, perhaps the dogs that were walked regularly might also be getting higher levels of human contact, socialization, and attention, although some internal analyses of the data by this research team suggests that this is less likely. Still because of the unexpected nature of the findings I am sure that other scientists will follow up on such possibilities in the process of trying to confirm whether something as simple as walking a dog on a regular basis can have such a dramatic effect.
In any event, the take away message seems to be that one easy and uncomplicated way of reducing stress levels and anxiety related behaviors in dogs might be to merely take them out for a daily walk.
Stanley Coren is the author of many books including: The Wisdom of Dogs; Do Dogs Dream? Born to Bark; The Modern Dog; Why Do Dogs Have Wet Noses? The Pawprints of History; How Dogs Think; How To Speak Dog; Why We Love the Dogs We Do; What Do Dogs Know? The Intelligence of Dogs; Why Does My Dog Act That Way? Understanding Dogs for Dummies; Sleep Thieves; The Left-hander Syndrome
Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission
* Data from: S. Cafazzo, L. Maragliano, R. Bonanni, F. Scholl, M. Guarducci, R. Scarcella, M. Di Paolo, D. Pontier, O. Lai, F. Carlevaro, E. Bucci, N. Cerini, L. Carlevaro, L. Alfieri, C. Fantini, E. Natoli, (2014). Behavioural and physiological indicators of shelter dogs' welfare: Reflections on the no-kill policy on free-ranging dogs in Italy revisited on the basis of 15 years of implementation. Physiology & Behavior, 133, 223–229.
