人の健康と動物たち
The Effects of Animals on Human Health東京農業大学 バイオセラピー学科 助教／ヒトと動物の関係学会 理事・内山 秀彦

Hidehiko UCHIYAMA, Assistant Professor, Tokyo University of Agriculture;
Board Director, Society for the Study of Human Animal Relations (HARs)

Hello everybody. I am Hidehiko Uchiyama.

Relationships between people and animals began to
become a topic in the 1980s, a few years before theI used to belong to Azabu University but I have

IAHAIO was established. The real starting point insince moved, from this year, to Tokyo University of

the field was marked by the Dundee meeting held inAgriculture. While at Azabu University I studied under

1979. Here, specialists in education, psychology andthe guidance of Prof. Mitsuaki Ohta for over ten years.

veterinary science gathered and discussed the idea

Today, I’d like to talk about what I was taught in thoseof holding a conference for the purpose of seriously

years, and also about the things I believe I should try toconsidering human-animal interaction and the effects

tackle from now on.

animals have on people. This movement eventually led
to the establishment of the IAHAIO in 1990.

The subject of my talk today is “the effects of animals
on human health”. Under this theme, I intend to talk

The IAHAIO holds conferences at three-yearly intervals.

mainly about the current state of animal-assisted

These conferences have taken place in Geneva in 1995,

therapy, or AAT, in this country.

Prague in 1998, Rio de Janeiro in 2001, Glasgow in2004 and Tokyo in 2007. I suppose some of you may

The foundation of AAT at the academic level is thehave been among the participants. I took part in thesubject of anthrozoology, which is the scientific study

Tokyo conference and the Stockholm conference, whichof the relationships between humans and other animals,

was held in 2010. At the Stockholm event, a wide range

or human-animal interaction. I would like you toof research and activities related to human-animal

understand that AAT is essentially a variant, or in otherinteraction were introduced.

words, an application model of anthrozoology.
In addition, in 1991, an organization called the
I would like to talk about the historical side of studying

International Society for Anthrozoology, or ISAZ, washuman-animal interaction. Perhaps this will basically beestablished as a support organization for the scientifica brush-up story for you. It concerns an association thatand scholarly study of human-animal interactions.

goes by the long name of “the International Association

ISAZ has held an annual conference each year sinceof Human-Animal Interaction Organizations” and1992, and its 2011 conference met in Indianapolis.

i s b e t t e r k n o w n b y t h e a c r o nym I A H A I O. T h e

This organization also publishes a quarterly academic

President of this association is Dr. Rebecca Johnson.

journal ent itled Anthrozoös. In 2006, another

IAHAIO was founded in 1990 as an internationalorganization called the International Society fororganization to bring together national associations

Animal-Associated Therapy, or ISAAT, was formed. Thisand related organizations interested in advancing theorganization has the mission of certifying educational

understanding and appreciation of the links between

institutions involved in AAT (animal-assisted therapy),

animals and humans.

AAA (animal-assisted activities), and AAE (animalassisted education).

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The attitude in the West towards proceeding withthem.

human-animal interaction and animal-assisted therapy
is based on the pragmatic standpoint of making positive

It is plainly obvious that the survival rates of cardiac

use of animals in human health. As was announced

disease patients differ significantly between thoseat the Stockholm conference, approximately 17% of

who have pets and those who don’t. And of course, pet

hospitals in Germany now have an AAT department

owners have better health results overall. In particular,

and 95% of medical professionals including generalsince dog owners go for walks with their dogs, they

practitioners recognize the efficacy of AAT. I myself

benefit from the exercise effect. Friedman made aconsider this efficacy to be a powerful fact that has notcomparison between dog owners and owners of otheryet been realized in Japan.

pet animals, but even those keeping animals other thandogs showed significantly higher survival rates thanSo, how has the subject of human-animal interaction

non-pet owners. This research is considered to be thebeen developing in Japan? The Society for the Study offundamental basis on which the study of human-animal

Human Animal Relations, or HARS, was established ininteraction rests.

1995. Currently, HARS and the Japan Animal Hospital
Association, or JAHA, are participating in the IAHAIO

J.M. Segal studied the relationship between owning a

as representative Japanese national members. In 2008,

dog and stress as measured by the average number ofa society called ‘Nihon Dobutsu Kaizai Kyoiku Ryoho

hospital visits people made. This research looked at

Gakkai’ was established in the same field, and this year

elderly people. Of course, when people get old, their

it was certified as an NPO. So the movement is gradually

physical functioning tends to deteriorate. In addition,

gaining ground. However, in the West, a movement thatmany older people become lonely after they are

was considering human-animal interaction seriously

separated from their spouse or their friends. On thishad already gained momentum by the 1980s. So simply

basis, elderly people can be divided into those facing

stated, regarding AAT and human-animal interaction,

many kinds of social stress and a group with low stress,

Japan is lagging behind the West by 15 or 20 years.

comprised of elderly people in general. When thesepeople are further classified into dog owners and non-At this point, I believe I should introduce you to

dog owners, we find a self-explanatory result which isanthrozoology, which serves as the basis for studying

illustrated by the average numbers of hospital visits

human-animal interaction. Yesterday, Dr. Rebecca

made by members of each group.

Johnson talked about this research field so there may
be some overlap between our accounts. But I intend toI have written that early prevention and healthgo into a great deal of detail.

maintenance are important ways of limiting increased
medical expenses that can be expected due to theThis slide shows the survival rates of patients withaging society. Even among the elderly, in the low-stresscardiac diseases following discharge from hospital.

group there is not a great difference in the hospital visit

This is a famous research paper by Friedman. In thefrequency between pet owners and non-pet owners, but

actual paper, a table of tests is shown. This shows thewhen elderly people are under very strong social stress,

results made into a figure, comparing pet owners with

the number of hospital visits made by pet owners is

non-pet owners. Furthermore, it compares owners who

significantly lower than the number made by those who

keep dogs with owners of other animals, and shows the

don’t keep pets.

survival rates of cardiac disease patients one year after
being discharged from hospital. Cardiac disease patients

This next slide shows the results of a survey into thetend to be physiologically weak. Even when only

emotional states of elderly women. The subjects of thisexperiencing mild stress levels their blood pressure

survey were classified by group into those who kept

can rise and put a burden on the heart sufficient to killpets and those who didn’t, and also into those who lived

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with their families and those who lived alone. When

Now, let’s look at what kind of changes happen tothese groups were compared, the results that emerged

pet owners’ bodies as a result of keeping, or being inwere very clear. The group that kept pets reported acontact with, their animals as measured by the number

reduced feeling of loneliness, improved control overof hospital visits they make or the changes in healththeir emotional ups and downs, a greater capacity

problems they experience.

to see things optimistically, and less susceptibility to
becoming disturbed or unsettled.

The research shown in this slide was conductedby Anderson. These readings show the maximumThis is a similar piece of research. This survey classified(systolic) and a minimum (diastolic) pressure. Thesethe subjects into those who kept pets and those who

are the measures figures for plasma triglycerides,

didn’t, and compared their daily level of spiritual

which indicate the blood viscosity, and for plasma

elevation, daily problems, satisfaction with life, sensecholesterol. These are the figures for the male group.

of positive hope, etc. The results show that people who

The white ones are for the group that didn’t keep pets

associated with pets on a daily basis ranked higher

and the yellow ones are for the group that did keep

across the board.

pets. Among male pet owners, systolic blood pressure,plasma cholesterol and plasma triglycerides values

This next piece of research, by James Serpell, is very

were low. Among females up to the age of 39, thereinteresting. It looked at the relationship between thewasn’t much difference between those who kept a pet

incidence of health problems and pet dog and cat

and those who didn’t. But for women over 40, we canownership. The health problems examined included

see a clear difference in the values of these indicators.

minor headaches and stomachaches that happen on an
everyday basis. During the first month after a group of

At this point, stress becomes a keyword. What kinds ofpreviously non-pet owners acquired a pet, they reported

bodily reactions occur due to stress? When a person

a highly significant reduction in the occurrence offeels the effect a stressor, what kind of reaction does

minor health problems. Actually, the group thatthe nervous system produce? These are autonomic

acquired a cat showed a slight improvement over thereactions. On the right side is the hypothalamic-

first six months, but for the group that acquired a dog

pituitary-adrenal axis (HPA axis) pathway, which

this improvement was maintained throughout the firsteventually leads to the secretion of that well-known

ten months. This research demonstrated that daily

hormone cortisol. Also involved are hormones such

health problems tend to decrease when people keep a

as cort icotropin-releasing hormone (CRH) andcat or a dog.

adrenocorticotropic hormone (ACTH). The nervous
system responds to stressors very quickly. The

All of this research says positive things about petmechanism is complicated. I teach this to students, butownership. But is this really the case? Just the otherit is difficult to get them to understand. Such a reaction

day, I read a book entitled Some We Love, Some We

occurs in response to such and such a stressor, forHate, Some we Eat by Harold Herzog. Maybe someexample, when you do some exercise, or when youof you have read it too. In that book, there are lots ofapply yourself to some task that is a little hard, suchreports concluding that animals have good effects on

as studying, or doing some chores that daily living

people both psychologically and physically. Also, there

requires. So it is better if you don’t think that it is bad

are a few reports stating that having pets doesn’t havefor these reactions to occur. Actually, it is necessary forany effect the health at all. In the book it also states thatthese reactions to take place on a daily basis.

the author asked Friedman, who I introduced earlier,

232“what effects do animals have on people?” Friedman

However, when this kind of thing happens continuously

answered, “animals certainly have a good effect onover a long period, cortisol tends to be secreted for apeople, but they are not a cure-all.”longer time in response to each new stressful incident,

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

and the sympathetic nervous system goes into a state

do feel healthier. And when a person feels healthier, theof protracted strain. This is the stress state.

number of hospital visits is lower as a matter of course.
This figure shows a chain linking dog-ownership with

Motooka’s research involved measuring the state ofowner health very clearly.

the parasympathetic nervous system by analyzing
the variability of the heart rate. This is because in

At this point, I am going to change the subject.

order to ease stress, we should pay attention to the

So far, I have been talking about various researchparasympathetic nervous system, which works infindings, but now I would like to tell you about theparallel with the sympathetic nervous system as part

IAHAIO 2007 Tokyo Declaration. It begins: “Given theof the autonomic nervous system. Heart rate variability

scientific and medical evidence proving the beneficial

analysis looks at the action of the autonomic nervous

effects to human health and well-being that arise

system in real time by analyzing the heart wave

from interactions with companion animals, given theinterval, which is the interval between successive R

biological and psychological evidence for the innate

waves. [An R wave is an upward deflection displayed onaffinity of humans to nature, including other living

an electrocardiogram (ECG).]

beings and natural settings,”

This is called the high frequency component, orFrom this standpoint it continues: “the members

HF. It is an indication of the work carried out byof the International Association of Human-Animal

the parasympathetic nervous system. For instance,

Interaction Organizations unanimously approved thewalking the dog enhances parasympathetic nervous

following resolution and guidelines for action at thesystem activity. The action of the system is much

IAHAIO General Assembly held on October 5, 2007

more pronounced when walking with a dog thanin Tokyo, Japan. It is a universal, natural and basic

when walking alone. When the parasympathetic

human right to benefit from the presence of animals.

nervous system is working actively it means that the

Acknowledgement of this right has consequences

sympathetic nervous system is in a relaxed state. Thisrequiring action in various spheres of legislation andslide shows that the effect produced by walking the dog

regulation. IAHAIO urges all international bodies anddaily becomes successively greater on the first, second

national and local governments...” And then it lists theand third days, etc. This is the result of comparing thefollowing stipulations.

parasympathetic nervous system in those who keep,
and those who don’t keep, a dog at home. As you can

The first stipulation is: “To enact housing regulations

see clearly, the action of the parasympathetic nervous

which allow the keeping of companion animals if theysystem is enhanced in those who keep a dog at home.

can be housed properly and cared for adequately,while respecting the interests of people not desiring

So far, we have looked at a variety of studies. Healy

direct contact with such animals.” This is followed

created a very convenient and very clear conceptual

by: “To promote access of specially selected anddiagram to show that dogs have a positive effect on

trained, healthy, and clean animals to medical carepeople’s health by considering the mental, physical andfacilities to participate in animal-assisted therapy and/psychological aspects of health, and he mapped out

or animal-assisted activities.” The third stipulation is:a health chain in dogs and their owners. Dog owners“To recognize persons and animals adequately trained

increase the amount of exercise they take, of course.

in and prepared for, animal-assisted therapy, animal-

And when their exercise increases, people can sleep

assisted activity and animal-assisted education,” andbetter. Their physical health improves, and this means

the fourth is: “To allow the presence of companion

they have a lower absentee rate from work. Moreover,animals in care/residential centers for people of any

one of the social effects of keeping a dog is that when

age who would benefit from that presence. The fifthpeople enjoys themselves with a familiar partner theyand final item on the list is: “To promote the inclusion

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of companion animals in the school curricula according

can be achieved. As I wrote in my summary, Jamesthe ‘IAHAIO Rio Declaration on Pets in Schools’.”

Serpell has said that there have been relatively few

However, let’s consider the actual situation at present.

scientific studies on this subject. So this is a matter ofLet’s try to visualize it. Already five years have passed

some concern in Western countries as well.

since this declaration was issued but, so far, it seems
that not even one of these stipulations has been realized

In our approach, oxytocin came up as one of thecompletely. Despite such a clear and concise declaration

substances related to human health. Oxytocin is abeing issued there has been little progress. Although

hormone that, among other things, stimulates thethere is no doubt that things are moving forward little

production of breast milk, although men produce

by little, nothing significant has been achieved yet.

oxytocin as well as women. In mother-childrelationships oxytocin concentrations are observed to

Healy, who I mentioned a little earlier, carried out arise. Beyond its role in milk production oxytocin haslarge-scale survey on pet keeping and human health inlong been regarded as a mysterious hormone. Indeed,

three countries simultaneously, namely Australia, China

in recent years it has also been called the ‘happy

and Germany. The survey revealed that the number

hormone’. Several researchers have been studyingof annual hospital visits paid by pet owners was 15 to

oxytocin with the idea that it can serve as a measure of

20% less than the number of visits paid by people who

the positive relationship between people and their dogs.

don’t keep pets. When this is converted into health carecosts, pet ownership is estimated to save the equivalent

Let’s look at a concrete research paper and its results.

of 754.7 billion yen in Germany and 308.8 billion yen

In one experiment, 55 “pairs” each consisting of a dog

in Australia. This research is comparatively recent.

and its owner interacted in a room for 30 minutes.

In Japan too, given the advance of the aging society,

The oxytocin concentration in the owners’ urine wasrising health care costs are unavoidable. In this context,

measured both before and after the interaction period.

the positive effect of keeping animals as pets is worth

In the case of the 13 owners who reported that theirhighlighting.

relationship with their dog was good, the oxytocin
concentration rose significantly. Conversely, in the case

In Japan, research has become an important toolof the 42 owners who reported their relationship within the drive to expand the positive health effects of

their dog was not good, the oxytocin concentration incontact with animals as widely as possible and also totheir urine did not change. However, even among thisbroaden the spread of AAT, AAE and AAA. So I would

latter group of owners, when they practiced eye-contact

like now to consider the direction that this research istraining (a basic form of dog training) in some cases

taking in Japan. It starts from the point that the healththeir oxytocin concentration did increase.

effects animals bring to people have already been
demonstrated scientifically and it goes on to examine

Earlier, I said that we should adopt an approach tothis subject in more depth so as to discover in what

how we build good relationships between people andways animals affect human health. I think this is a very

animals. In this experiment, among the 55 dog owners,

important subject.

only 13 reported having a good relationship with
their dogs. That is about 23% of the total. We can’t say

We need to pursue more deeply the mechanisms byanything for certain because the experiment was only

which these various changes occur, and we need tocarried out with 55 dog owners. Still, I think we should

further our research into the significance of bettertake note of what the results suggest about people who

relationships between people and animals. Also it ishave good relationships with their dogs.

essential to conduct this research based on a scientific234

approach containing both quantitative and qualitative

Something else to which I have been paying attention isanalysis, and using methods by which reproducibility

brain activity measurement using NIRS (Near Infra-Red

りぶ・らぶ・あにまるず 神戸アニマルケア国際会議 2012

Spectroscopy), a technique that Hitachi Ltd. has named

etc. I was studying the kinds of change that can be‘optical topography’. Optical topography systems areobserved in brain activity when the subjects touched agroundbreaking measurement devices that have beendog, looked at a dog, touched a cat, or looked at a cat,

attracting a lot of attention recently. They are capable

respectively. At this point, a dog or a cat was brought in.

of measuring the activity of the cerebral cortex, other

When the dog or cat appeared, just by seeing the dog,

parts of the brain, and changes in nerve activity.

this person’s brain activity went up this way. Then it
rose like this when they touched the dog. In the case ofOriginally, optical topography systems were huge andcats, the changes were even more significant. Someone’

expensive devices. But recently they have become quites brain activity went up by this much when they saw

compact and easy to use. It was difficult to employ thethe cat, and by this much when they touched the cat.

earlier optical topography systems for animal-relatedThis experiment was performed with only a small

experiments. This is the screen of the measurement

number of subjects, so we can’t conclude anything fromdevice. A band is first wrapped around the subject’

it unless we analyze the results in detail. However, thes head and then the waveforms from each brainchanges were observed for sure. But in the case of one

measurement site are shown on the screen. There are

person brain activity did actually decrease.

16 channels and 16 spots, in either blue or red, andthese waveforms are displayed for each measurement

I have been thinking about what it is about animals

site. Optical topography measures the changes inthat are good for human health and how, by using suchoxygenated and deoxygenated hemoglobin at each ofmonitoring devices, we can discover at what point andthese sites.

by what mechanism the effects of animals appear. I
have personally experienced using this device, and I

This is a video I recorded of an NHK Special

would like to show you what happened. Unfortunately,

documentary on the treatment of depression. The

it is rather difficult to see. Time is shown along thisprogram shows this device being used. Let us look at

axis. This is one minute. Changes in brain activity are

the video for a short while. (Video projection)

shown here. Now, it’s going up a little. I must have had
a thought about something. This is such a sensitive

As you saw, the subjects are provided with various

machine, so it is rather difficult to use. At this point, akinds of stimulation. For example, they can be asked

dog appeared. Let us look at a video as I issue various

to think about a word. They can be given a different

commands to the dog.

subject and the changes in their brain activity can be(Video projection)observed as they think about it. It can be used as one
index in depression testing. When a mentally healthy

This was a very good dog. He obeyed me well which

person undergoes this test while being monitored bypleased me. Look at this channel 7. You can see theoptical topography, the indications rise significantly

indication is up. I think it suggests that when a dog

when the subject is asked to think about one particularobeys my commands, or when communication with theword. But in the case of a depressed person thedog goes well, the indicator goes up.

indications do not rise very much. This is especiallyconspicuous in the case of the frontal lobes. I suppose

My guess is that, from these experiments, we can comethat since this particular experiment was shown on

to an understanding of what it is about human-dog

television, there might have been some exaggeration,interaction that most influences human brain activity.

but in the most advanced research quantification of the

It might be the ‘contact with’, ‘issuing commands to’,results may have progressed.

or simply ‘touching the animal’. Also, regarding mybackground, I am not a dog trainer and I don’t have

I carried out the following experiment personally. Theremuch experience with dogs. When people such as dog

were five subjects, represented here as Mr. A, Mr. B,

trainers who are used to handling animals took part in

2nd Live Love Animals International Conference on Animal Care in Kobe 2012235

this experiment, the changes in brain activity that wereobserved were not very large.
Here are the results of my experiment. You can see
this part rises in a vague way. But even though I only
underwent this experiment for one or two minutes, asignificant change is visible.
From this point, represented by the dotted line, the dog
appeared. This is the part where I am giving commands.
Channel 7 is this part. Seeing this alone, I think theexperiment is very interesting. I intend to continue thisresearch.
This is an overview of animals appearing in AI (artificial
intelligence) studies, based on a collection of study
results published over the past ten years. The results
show that, in the overwhelming majority of cases,
dogs were used. AI studies commonly use pet dogs as
subjects of study while ordinary dogs are used for AAT.
Not many cats appeared in these studies. I have also
looked at research published in Anthrozoös over the
past decade. Here too, dogs made up the overwhelming
majority of study subjects although there are a few
studies using dolphins and horses. Cats appeared rarely.
However, if we think paradoxically, we should consider
experiments using horses and cats as well.
This scene shows a compact optical topography system.
The device is placed on the subject’s back and the band
tied around the subject’s head. This is the point in the
middle of an experiment. The researchers are paying
attention to changes occurring in brain activity when
the subject gets onto a horse and how this change
differs from what is observed during interaction withother animals.
When I obtain new research results I would liketo report them to you. For now, that completes mypresentation. Thank you very much for your attention.

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