The Hug Factor

One goal of longevity researchers is to keep your body from aging and dying for as long as possible. The other is to preserve your brain. Oddly enough, the secret to both may lie in childhood, I gestures as natural as a hug between mother and child or as purposeful as a little extra stimulation.

Stanford University researcher Robert M. Sapolsky thinks it may have more to do with the latter, at least in case of rats. For them, he surmises, it all happens in the first three weeks of life.

During a 21-day period, Sapolsky and his colleagues briefly handled new born rat pups, placing them in a different cage for a mere 15 minutes a day. For rest of their lives, they received exactly the same treatment as other lab rats. As the pups grew older, their achievements were nothing short of miraculous. At 28 months – quite elderly for a rat, according to Sapolsky – the rats who received extra stimulation as infants ran mazes as well as did rats in their prime. That’s pretty incredible, given that aged rats predictably become forgetful about mazes. Even more incredible: When Sapolsky examined the brains of several rats after death, he found none of the usual cell loss in the hippocampus, a region crucial to learning and memory. It was as if the rodents had drunk from the fountain of youth.

Sapolsky discovered that in rats, the early touching experience, along with exposure to a new environment, causes the brain to put a brake on one type of stress response. The brain develops receptors that inhibit the secretion of adrenal hormones called glucocorticoids. Sapolsky says these stress hormones are “disaster to have in the blood-stream.” Over time, they attack the cells of the hippocampus so that by old age rats, monkeys and humans have lost 10 to 20 percent of memory-critical gray matter.

But in the rat population, a little extra stimulation soon after birth seems to have a lasting effect on the brain, protecting it from damage at the very end of life. That doesn’t mean you should hang fancy musical mobiles over your newborn’s cradle, however.

To begin with, Sapolsky warns that what holds true for rats may not be so for humans. He also doesn’t know what aspect of the stimulation prompts the altered stress response. “One thing we do know it’s not is affection,” he says. “Nor is it the ability to build a tolerance to stress – ‘stress immunization,’ as it used to be called. We know the animals weren’t stressed during handling because they’re not secreting stress hormones.” He is also sure that for rats, at least, the phenomenon occurs during the critical first three weeks. “It’s like setting a thermostat,” continues Sapolsky, “in that it teaches the brain forever after to make more of these stress-inhibiting receptors.”

The implications are profound. “Previously, we thought, ‘Well, this is how the brain normally ages,’ ” says Sapolsky. “But aging need not be normal or inevitable. The other message is that something incredibly subtle that occurs way back in infancy may protect the brain forever.”

LOVE WELL, LIVE LONG

While cuddling rats should not be equated with hugging babies, other scientists are finding that warmth and affection during childhood may counter the effects of human aging. Ask a cross-section of your friends why people today enjoy longer lives than those who lived, say, during the Hundred Years War. Their answers may range from Penicillin and coronary bypass to modern sanitation and absence of plague. Dr. Leonard A. Sagan, an Atherton, California, epidemiologist, thinks the 30-year leap in life expectancy in the 20th century has more to do with Drs. Spock and Brazelton than with Drs. Pasteur and Salk. Americans live longer today because our minds are healthier, claims Sagan, the author of a controversial epidemiological study, The Health of Nations.

“Modernization has led to a rise in hopefulness and a decline in helplessness,” says Sagan. “The hopeful personality is more resistant to disease and better able to cope with stress.”

The key reason for improved mental health dates back to our bassinet days. “Before beginning the study, I assumed parents always cared for their children, but that’s not true,” explains Sagan. In the 19th century, children were viewed as miniature adults and subjected to harsh discipline, authoritarian attitudes and a children-should-be-seen-and-not-heard philosophy. With modernization came smaller families, more nurturing and greater physical intimacy between parent and child.

“Imagine two babies crying,” says Sagan. “The mother of one picks it up, cuddles it and asks, ‘What’s wrong?’ As a result, that baby feels he has some mastery over his environment. The other baby is left to cry alone in his crib. He feels helpless, worthless and unloved. And that is what determines whether one will live to be 90 or become an alcoholic and die at 50.”

Safety in Numbers

You can’t recreate a loving childhood any more than you can relive an exciting infancy (though perhaps your children can benefit from this information). What you can do to enhance your chances for longevity: Don’t be a loner.

Social scientists have known for decades that isolated people tend to die at a younger age than do those with full social lives. What they didn’t understand: Does a lack of social relationships predispose a person to early death? Or is it that unhealthy individuals simply don’t socialize as much? Or is there some misanthropic personality trait that leads to both social isolation and poor health? Now James S. House, chairman of sociology at the University of Michigan, and colleagues have reviewed the key data and concluded that “a lack of social relationships constitutes a major risk factor for mortality.”

One survey queried 4,775 people in Alameda County, California, about four types of social ties: marriage, contacts with family and friends, church membership and other group affiliations. Those who scored low on the combined “social network index” were twice as likely to die in the following nine years. If that’s not enough to inspire you to join the Rainbow Girls, House turned up a mortality rate two to three times higher for unsociable men among 2,000 Tecumseh, Michigan, adults, and up to twice as high for unsociable women. Even among laboratory animals, social ties have been shown to protect against stress-related diseases.

In fact, the evidence linking social isolation and earlier death is stronger than that linking the notorious Type A behavior pattern with heart disease. And the age-adjusted mortality risk is about the same as that documented in the Hammond report on cigarette smoking that prompted those scary warnings from the Surgeon General. What’s more, as a Yale scientist once noted, hidden within the Hammond report are plenty of other intriguing mortality statistics – among them that for men, at least, being divorced is only slightly less dangerous than smoking a pack or more a day.