"Healthiness is a warm puppy"?

More than 40 years after the creator of the comic strip "Peanuts" gave us his simple but inspired definition of happiness, researchers are finding that the family pet deserves more credit than Charles Schulz gave him.

Of course, warm puppies, kittens, and companion animals of all kinds make us happy. But a growing body of evidence suggests they also help us live longer, healthier, and more satisfying lives. Although pets might not be for everyone, studies show that for many they help reduce hypertension, improve the odds of surviving a heart attack, and stave off depression. They can strengthen one's marriage, reduce health care costs, and simply bring joy into a person's life.

"Some people like to listen to music," says Karen Allen, a researcher at the State University of New York at Buffalo who studies the health benefits of pets. "Some like transcendental meditation. For those who like animals, it seems pets just add something to life that is totally different from , the companionship of people."

How exactly animals work their magic remains something of a mystery. Obviously, psychology plays a part. Pets make good company, for starters, because if they judge us, they keep quiet about it. Since they require caretaking, they also compel people to look beyond themselves and their problems. Dogs in particular get folks out of the house and often lead to social interactions. No doubt, there's a tactile element, too, a deep-seated comfort that comes with petting a soft, friendly creature.

These days, research is bearing out what was once mostly left to conjecture and anecdote. For example, Sandra B. Barker and Kathryn S. Dawson of the medical school at Virginia Commonwealth University studied the effect of therapy dogs on the anxiety levels of hospitalized psychiatric patients. The 230 test subjects in the 1998 study had a wide range of diagnoses, including depression, bipolar illness, and schizophrenia. Almost all showed a significant drop in anxiety thanks to the animals. The exception-those with substance abuse disorders-could be attributed to withdrawal symptoms, the authors suggested.

"When a dog is in the room, it kind of deinstitutionalizes it," says Barker. "Patients are ready to reach out, touch, and interact in a way they can't with other human beings. They don't need any formal introduction. They don't need to build up a relationship as you do with humans."

Animals also help to rebuff the ravages of isolation, loneliness, and depression, as studies of the elderly, single people, prisoners, and the sick have shown. A 1999 report from UCLA indicates that pet ownership significantly reduces the likelihood of depression in men with AIDS. The study looked at the incidence of depression in gay or bisexual men, comparing a healthy control group to pet- and non-pet-owning AIDS sufferers. It indicated that those who were sick but enjoyed the companionship of an animal are twice as likely to become depressed. But for those without a pet, the chance of depression is far greater-three times the rate of the healthy group. This kind of healing power is one of the reasons behind programs such as the MSPCA's Phinney's Friends (see "Testament to a Healing Bond"), which helps owners with AIDS and their pets.

Yet research indicates that animal companionship offers more than a psychological boost. The cardiovascular benefits of having a pet, for instance, are well documented. An oft cited 1980 study by Erika Friedmann, Aaron Karcher, and others found that one year after being released from a New York hospital's coronary unit, individuals with pets showed significantly better chances of survival than those without animal companionship. Eleven of the 39 patients with no pets died during that year, compared with 3 of the 53 who lived with pets.

In 1995 Friedmann spearheaded a similar study, this time tracking an even greater pool of heart patients. She reported that just 1 of 87 pet owners died within a year of being released from the hospital. Of the 282 who had no pets, 19 died. The odds of surviving a heart attack, this suggested, are close to nine times better for those who have a pet.

Several years ago, Allen compared pet-owning and non-pet-owning stockbrokers who were on medication for high blood pressure. When the greatest stress hit, she found, those with either a cat or a dog showed greater signs of stability. Their heart rates, blood pressure, and key enzymes all stayed within an acceptable range. The others, though, saw theirs climb almost as high as when they first sought treatment.

"No one really knows the physical mechanism by which this may work," says Allen. Preliminary investigations, however, indicate that one way or another, having a pet seems to contribute to the production of neurochemicals that help maintain lower blood pressure.

Allen has endeavored to find out exactly what goes on between people and their pets to set such wheels in motion. In a yet-to-be-published study, she had people rate their interactions with their animals and keep diaries of what transpired. "People talk a lot to their animals," she found. "And they often rated interactions with pets much higher than those with other people, such as coworkers."

And though Allen herself has not studied the effects of pets other than dogs and cats, she considers it likely that anything from a gerbil to a snake could be beneficial. "If you're in love with your snake," she says, "it's going to have the same effect. Now, if somebody shows you a snake and you don't like snakes, it won't."

Allen is partial to dogs, in particular her 13-year-old Border collie, Flannigan. In his company, she says, the weight of the world falls away. If she pays close enough attention, she even notices that her breathing and pulse tend to slow down. "I can't imagine life without a dog," she says wistfully. "I know some people like to have a whole group of them. But I have to have one, one that I love and bond with, that's the center of everything."

This winter, a few days after six to seven feet of snow shrouded the New York hinterlands, Allen was nowhere to be found when she was called for one or two final questions for this article. She called back and explained that she and Flannigan had been out for a walk, breathing the chilly air and enjoying the scenery together.

Sometimes happiness is a cold puppy.