A recent search on Amazon.com reveals that 73,934 books with “stress” in the title are currently on the market. Without looking up each individual entry, it is a safe bet that most of them tell you how to ﬁght stress or avoid it entirely. Two years ago, I joined Bruce S. McEwen, Ph.D., of Rockefeller University, in writing a book called The End of Stress As We Know It, which took a slightly different approach. We argued that human beings, mammals, and even many ﬁsh are biologically endowed with the ability to cope with change, even when that change is perceived as stressful. Many of our lifestyle choices—chief among them diet, exercise, and nurturing our social connections—not only fend off stress-induced illness but also actively enhance the very processes in our bodies that help to protect us. The End of Stress as We Know It predicted that, very soon, science would take a good look at the other side of the coin: the things that go on when we are not under stress and that help mind and body to calm, heal, and grow.
Now Swedish physiologist Kerstin Uvnäs Moberg has done just that with The Oxytocin Factor: Tapping the Hormone of Calm, Love, and Healing. In a readable, personable account, she explores what she calls the calm and connection system and its pivotal hormone, oxytocin. Just as dynamic and as valuable as the more well-known ﬁght-or-ﬂight response, the calm and connection system, she says, “is associated with trust and curiosity instead of fear, and with friendliness instead of anger...When peace and calm prevail, we let our defenses down and instead become sensitive, open, and interested in others around us. Instead of tapping the internal ‘power drink,’ our bodies offer a ready-made healing nectar. Under its inﬂuence, we see the world and our fellow humans in a positive light; we grow, we heal.”
Uvnäs Moberg is a professor of physiology at the prestigious Karolinska Institute in Sweden, but it was her experience as a mother that drew her to study oxytocin. The heightened calm that she felt during pregnancy, nursing, and closeness with her four children was the opposite of the feelings associated with the challenge, competition, and performance that she said characterized her life as a scientist. She found her explanation in the scientiﬁc literature about oxytocin.
A MULTIFACETED HORMONE
First discovered in 1906 by the English scientist Sir Henry Dale, oxytocin is a hormone created in the neurons of the hypothalamus, a gland located just under the thalamus in the brain, and also secreted elsewhere in the brain and in the ovaries and testes. Oxytocin is best known for its role in inducing labor and stimulating the expulsion of breast milk. When Uvnäs Moberg began her own research, animal experiments had already shown oxytocin enhanced the relationship between mother and offspring. “Could it be,” she wondered, “that oxytocin also affects human beings in such ways, as well as others that we are not aware of, both physically and psychologically?”
On the basis of what Uvnäs Moberg learned and other research, the answer is yes: oxytocin affects animals and humans, male and female, behaviorally and physiologically, in a staggering number of ways. When injected into experimental animals, oxytocin leads to less aggression and more sociability; it accelerates mating and could make conception more likely by speeding the transport of egg and sperm. Oxytocin acts in the brain to stimulate maternal behavior in female rats, even those who have never given birth. Animals given oxytocin injections in the presence of other animals will recognize and bond more readily with those individuals. The hormone decreases pain sensitivity and improves animals’ performance in conditioned-memory tasks.
Equally impressive are the hormone’s physiologic effects. Oxytocin acts as a kind of thermostat, lowering blood pressure and helping blood vessels expand and contract to maintain an even distribution of body heat. It dilates the blood vessels on the face and chest in nursing women and in fathers holding their babies, helping to warm the newborn. Oxytocin facilitates digestion in animals with full stomachs but retards digestion if the stomachs are empty. It lowers levels of stress hormones, regulates the balance of ﬂuids in the body, and stimulates cell division and the healing of wounds.
From digestion to breastfeeding, from reduced anxiety to improved memory, the actions of oxytocin have a cumulative outward-directed effect, in contrast to the defensive, protective effect of the ﬁght-or-ﬂight response.
The net result of these many behavioral and physiologic effects is overwhelmingly positive. As food becomes bone, muscle, and fuel, as wounds heal, the body grows; as relationships form with friends, spouse, and children, the individual’s life is nourished and family and community are strengthened. From digestion to breastfeeding, from reduced anxiety to improved memory, the actions of oxytocin have a cumulative outward-directed effect, in contrast to the defensive, protective effect of the ﬁght-or-ﬂight response.
TAPPING THE “INTIMACY HORMONE”
We know that physical contact is at the heart of how we calm and connect, so it comes as no surprise that touch accomplishes many of the same things as does oxytocin and, in fact, often triggers its release. Repetitive, soothing touch decreases the pain of labor, reduces postpartum depression, and helps babies thrive; Uvnäs Moberg even cites a study showing that people borrowing books from the library were more likely to return their books if the librarian touched them lightly during checkout. The importance of psychological closeness with others is also clear. A preponderance of medical literature shows that people with good, close relationships have stronger immune systems and less cardiovascular disease; breast cancer patients survive longer and AIDS patients report less pain when they have satisfactory relationships in their lives.
A ﬂood of oxytocin is released during sex and orgasm, but the book does not go into this effect in detail. A less daunting setting in which both oxytocin and touch play a key role is massage, which, says the author, “…generally has an anxiety-reducing, calming, and relaxing effect on children and adults. For example, experiments in a juvenile psychiatric clinic showed that regular massage made the young patients calmer, less depressed and anxious, and more cooperative than the members of a control group that did not receive massage.” The results of massage track with those of oxytocin: lower levels of stress hormones, lower blood pressure, less anxiety, and increased learning (in one experiment, subjects found it easier to solve math problems after a massage). In Sweden, regular massage helped schoolchildren become calmer and more socially mature; the biggest difference in behavior was seen in the most disruptive boys, who became less aggressive and more social.
Many of the ways in which people try to raise their own oxytocin levels can be either beneﬁcial or destructive, Uvnäs Moberg observes. An “internal massage” in the form of a good meal releases the hormone cholecystokinin from the small intestine, triggering oxytocin release and bringing about feelings of postprandial calm and well-being. Alcohol, cigarettes, and many “recreational” and prescription drugs— including antidepressants, in the author’s belief—inﬂuence levels of oxytocin. Exercise and meditation work on the body in ways that mirror the effects of oxytocin, though there is no hard evidence that they actually affect oxytocin levels.
BALANCING SCIENCE AND ENTERTAINMENT
Uvnäs Moberg’s presentation is, for the most part, clear and comprehensible. She describes an area of research that has not, until now, had any fanfare and discusses its relevance in our lives. Although the press material describes the book as intended for a general audience, it is also a quick, smooth read for scientists, clinicians, and science teachers. In general, the author succeeds at speaking to both kinds of reader. But the book illustrates the difﬁculties inherent in trying to walk this line—difﬁculties with which, as a science communicator myself, I sympathize.
Readers with a background in science might ﬁnd that some phrases aimed at the lay audience begin to grate after a while, even the much-mentioned “calm and connection system.” “Signaling substances” is another such phase, particularly when Uvnäs Moberg distinguishes between oxytocin’s effects as a hormone (released from the pituitary and acting on bodily organs) and when it is released from axons and acting on other neurons. In the latter case, why not call a neurotransmitter a neurotransmitter? Similarly, amid a level of detail that includes the frontal and dorsal lobes of the pituitary and the supraoptic and paraventricular nuclei of the hypothalamus, use of the term “signaling substance” seems oddly coy.
An audience of scientists might also wish for a broader view of the research. For example, Uvnäs Moberg presents the hormone vasopressin as the yang to oxytocin’s yin, released in the brain during such macho activities as boundary setting and defense of territory. Yet Larry Young at Emory University and Thomas Insel, now director of the National Institute of Mental Health, have showed the effects of vasopressin to differ widely between species, depending on where its receptors are distributed in the brain. In one provocative study they cloned the vasopressin receptor of the gentle, monogamous prairie vole; when this receptor was transplanted into male mice, subsequent vasopressin injections made the mice more solicitous of their female cage mates than they normally would have been. This distinction might not be necessary for lay readers, but scientists might wonder why the point is not made at least brieﬂy. In another such example, during the discussion of oxytocin and exercise, the author does not mention that growth hormones and neurogenesis are also increased by exercise—although she does note, in other parts of the book, that oxytocin stimulates both of those things. A caveat appears early on, warning that the book cannot be a comprehensive summary of all available research on the subject, but connecting the dots between the author’s work and related, well-known research would not have made the book appreciably longer.
A caveat appears early on, warning that the book cannot be a comprehensive summary of all available research on the subject, but connecting the dots between the author’s work and related, well-known research would not have made the book appreciably longer.
However, the lay readers for whom the book is primarily intended might ﬁnd the tone too detached. The book abounds with lecture-hall phrases like “as we’ve seen” and “which we’ll discuss in a later chapter.” Depending on the reader’s taste, these phrases can come off as pedantic or endearingly nerdy. I myself lean toward the latter view. In a culture in which popular science tends to be hyped up at the expense of accuracy, the author’s professorial tone lends a certain cardigan-sweater integrity, but it might be off-putting to readers accustomed to jazzier prose.
The science could have been made more entertaining without any loss of credibility, perhaps by describing the studies in a more narrative way. After Uvnäs Moberg tells us that her interest in oxytocin began through nursing and nurturing her children, she more or less drops out of the story. Hearing about some of her early forays into this ﬁeld would help to sustain the interest of nonscientiﬁc readers, while giving professionals a personal glimpse that they would not get from journal articles or textbooks. How did she begin studying oxytocin? What effects did she ﬁrst look at, in what situations? Did she ﬁnd what she expected or was she surprised? Whose idea was it to test the effects of oxytocin in males? We can always check the references, but it would be nice to hear the story from the author—especially because she says that the whole “calm and connection” theory was in opposition to the prevailing trend, which focused on ﬁght, ﬂight, and defense. Some of the biggest movers and shakers in the ﬁeld considered themselves mavericks, like Hans Selye, who ﬁrst described the coordination between the nervous, endocrine, and immune systems in response to what he called nocuous stimuli, and John Mason, who provided the ﬁrst evidence linking these reactions to psychological stress. Uvnäs Moberg is one of a line of pioneers; she has no need to be shy.
Of the missed opportunities to spice up the science, the most conspicuous example, ironically, is the chapter about sex. The book states several times that levels of oxytocin increase during lovemaking. Any reader will wonder how scientists go about establishing such a thing. After turning to the reference section and logging onto MEDLINE, I found a study in the Journal of Clinical Endocrinological Metabolism titled “Plasma oxytocin increases in the human sexual response.” The researchers measured oxytocin levels in men and women “before, during, after private self-stimulation to orgasm.” Blood samples were collected from catheters in the subjects’ veins; to check other parameters, electrodes connected “an anal device” to a polygraph in an adjacent room. The subjects indicated orgasm by pressing a signal. As neuroscience abstracts go, this one is pretty lively—unintentionally, no doubt. But The Oxytocin Factor merely says that “…oxytocin levels rise powerfully in the blood of both males and females and reach maximum concentration with the release of orgasm.” Although it is obviously not the author’s style to get cute about something like this, she seems to go out of her way to make the material dull. The result is, well, an anticlimax.
WHERE DOES OXYTOCIN TAKE US?
These are minor ﬂaws, if they are ﬂaws at all. When writing about science accessibly, decisions about what to include and how have to be made, and, in general, Uvnäs Moberg acquits herself well. Ultimately what The Oxytocin Factor could use more of is Uvnäs Moberg herself. Reticent though she is, enough of her personality comes through that we would like to hear more about what she thinks. Especially welcome would be a brief closing chapter detailing how things might change—in the laboratory, the doctor’s ofﬁce, and society in general—once the effects of oxytocin are better understood.
Ultimately what The Oxytocin Factor could use more of is Uvnäs Moberg herself. Reticent though she is, enough of her personality comes through that we would like to hear more about what she thinks.
“We humans must begin to think of our health and well-being as our own inner ecology,” she writes. “Our bodies will not continue to work well if we constantly overexert them and exploit their resources. We need to replenish our empty stores, regain our strength, rest, and heal. We have known this for a long time, of course, but only now are we beginning to understand the physiological processes involved and the ways we can consciously choose to activate them. If we really understand how we function physiologically, we might become part of a shift, both individual and cultural, away from the stress-oriented imbalance of modern society.”
One could wish that Uvnäs Moberg had outlined this potential shift in greater detail; readers have to construct it for themselves, even though the book provides many interesting nuggets. The author is at her most eloquent when she urges us to make positive choices in our lives, to activate the oxytocin system in healthful ways—massage, exercise, meditating, and spending time with people we like. She advocates massage as a way to address behavioral problems in children, although she notes that this is more likely to be successful in a country such as Sweden, with a strong tradition of therapeutic massage, than in the United States, where teachers are essentially forbidden to touch the children in their classroom.
In the context of making wise lifestyle choices, she does take advantage of the opportunity to talk about sex and sets forth oxytocin’s ability to promote intimacy and bonding as an argument against promiscuity: “Pregnancy can be protected against, but there are no pills … to protect the bonding that accompanies an intimate relationship, thanks to oxytocin. There is always a risk that emotional bonds will become powerful before the partners know enough to be sure that they are right for each other.” She also notes that risky sex (involving pain, violence, or fear) activates the ﬁght-or-ﬂight mechanism “in the form of higher blood pressure, tightened muscles, and even reduced emotional responses and desensitization to touch.”
Practitioners of the more “alternative” therapies will ﬁnd themselves vindicated once the effects of oxytocin are more widely appreciated. Not all massage therapists or others involved in hands-on care of patients require empirical proof of their own contributions. But the author writes that acknowledgment of the role these professionals play in promoting growth and healing is much needed. “The prevailing belief in the technological and pharmacological elements of medicine is so enormous that the conﬁdence of these professionals in their own caregiving as a therapeutic method has been eroded, even though many patients who have recovered through this type of care can testify to its importance and effectiveness.” The oxytocin story could also help bring acupuncture into the fold of Western medicine. Uvnäs Moberg’s own work shows that the pain-killing effects of acupuncture vanish when subjects are given oxytocin blockers.
In fact, all of her remarks about oxytocin and pain are intriguing. After oxytocin injections, experimental animals take longer to show signs of pain. “It is probably not that the pain impulse...is registered as weaker, but instead that the reaction to the message of pain diminishes,” the author writes. The ability to block pain at the level of perception, not transmission, would be a coup in the ﬁeld of anesthesiology.
Even more provocative is a study in which rats became less sensitive to pain when they shared a cage with a rat that had been injected with oxytocin, even though they had received no injection themselves. Oxytocin antagonists eliminated this “analgesia by association,” as did temporarily blocking the animals’ sense of smell, suggesting that the calming effects of oxytocin can be transferred between individuals by smell, perhaps by pheromones. One wonders where this sort of research might lead. Some books about spirituality state that a group of people meditating can have a calming effect on people nearby who are not meditating, for example, and the “alternative” practice of aromatherapy is already alive and well.
Uvnäs Moberg does discuss these ﬁndings and their implications, but she avoids a closing ﬂourish in the form of a blueprint for the post-oxytocin future of scientiﬁc research. Perhaps she does not want to provide fodder for New Age zealots who might draw unjustiﬁed conclusions. As it is, readers of a more holistic, mind-body persuasion are likely to extend some ﬁndings beyond the comfort zones of many scientists. For example, unlike stress hormones such as cortisol, which have a built-in mechanism for shutting off their own production, oxytocin has a positive-feedback effect on itself—the release of oxytocin stimulates the release of even more. Furthermore, if oxytocin-producing cells in the brain are powerfully stimulated, all of the nearby cells begin to act in concert.
By explaining that “we are intrinsically structured to be able to connect, nurture, rest, reﬂect, and rejoice,” she urges us to value the calm and connection system at least as highly as the competition, achievement, and power associated with ﬁght or ﬂight.
Uvnäs Moberg notes that “coordination, whether of cells, effects, or individuals, is a marker for oxytocin.” Some readers might take this to mean that women have been increasing their oxytocin levels down the ages, through childbirth, breastfeeding, and caring for children—as well as through repetitive, tactile activities like milking cows, spinning wool, and hoeing corn—transforming themselves into nurturing, cooperative beings in the process, while the men, presumably, were off starting wars. But, of course, such a generalization cannot be made by observing the actions of brain cells. Scientists would not like it, and neither would most feminists.
In the end Uvnäs Moberg strikes the right balance. By explaining that “we are intrinsically structured to be able to connect, nurture, rest, reﬂect, and rejoice,” she urges us to value the calm and connection system at least as highly as the competition, achievement, and power associated with ﬁght or ﬂight. But she does so by sticking to the available research and explaining how the oxytocin system works, foregoing brave-new-world predictions about the future of science or society. In this way she provides a solid platform of information about a new area of research, coming across as both credible and open-minded.
From The Oxytocin Factor: Tapping the Hormone of Calm, Love, and Healing, by Kerstin Uvnäs Moberg. © 2003 by Kerstin Uvnäs Moberg. Reprinted with permission of De Capo Press.
The neglected physiological pattern that I will describe in this book is the opposite pole to the fight or flight reaction. Like most other mammals, we humans are able not only to mobilize when danger threatens but also to enjoy the good things in life, to relax, to bond, to heal. The fight or flight pattern has an opposite not only in the events of our lives but also in our biochemical system. This book deals with the other end of the seesaw, the body’s own system for calm and connection.
This calm and connection system is associated with trust and curiosity instead of fear, and with friendliness instead of anger. The heart and circulatory system slow down as the digestion fires up. When peace and calm prevail, we let our defenses down and instead become sensitive, open, and interested in others around us. Instead of tapping the internal “power drink,” our bodies offer a ready-made healing nectar. Under its influence, we see the world and our fellow humans in a positive light; we grow, we heal. This response is also the effect of hormones and signaling substances, but until now, the connections among these vital physiological effects have not been fully recognized and studied...
The calm and connection system is most often at work when the body is at rest. In this apparent stillness, an enormous amount of activity is taking place, but it is not directed to movement or bursts of effort. This system instead helps the body to heal and grow. It changes nourishment to energy, storing it up for later use. Body and mind become calm. In this state, we have greater access to our internal resources and creativity. The ability to learn and to solve problems increases when we are not under stress.
I believe that it is extremely important to increase our understanding of the physical and psychological workings of this antithesis to the fight or flight system. We need both, since for each individual in each situation, there is an optimal way to react. But it is now well known that long-term stress can produce a variety of psychological and physical problems. If we are to be healthy in the long run, the two systems must be kept in balance.
The line of research a scientist chooses to explore is not the result of chance. I believe we select our direction of inquiry based on a combination of personal experiences, the spirit of the times, and the political climate in our profession. Unconscious memories and experiences also play a role, perhaps more that we suspect. Out of this mix, we set up hypotheses that we work to prove or disprove; then we formulate questions that we try to answer.