Happiness study Harvard

Do happier people live longer—and, if so, why?

These are the kinds of questions that researchers are asking as they explore a new—and sometimes controversial—avenue of public health: documenting and understanding the link between positive emotions and good health.

A vast scientific literature has detailed how negative emotions harm the body. Serious, sustained stress or fear can alter biological systems in a way that, over time, adds up to “wear and tear” and, eventually, illnesses such as heart disease, stroke, and diabetes. Chronic anger and anxiety can disrupt cardiac function by changing the heart’s electrical stability, hastening atherosclerosis, and increasing systemic inflammation.

Jack P. Shonkoff, Julius B. Richmond FAMRI Professor of Child Health and Development at HSPH and at the Harvard Graduate School of Education, and Professor of Pediatrics at Harvard Medical School, explains that early childhood “toxic stress”—the sustained activation of the body’s stress response system resulting from such early life experiences as chronic neglect, exposure to violence, or living alone with a parent suffering severe mental illness—has harmful effects on the brain and other organ systems. Among these effects is a hair-trigger physiological response to stress, which can lead to a faster heart rate, higher blood pressure, and a jump in stress hormones.

Focusing on the positive

“But negative emotions are only one-half of the equation, ” says Laura Kubzansky, HSPH associate professor of society, human development, and health. “It looks like there is a benefit of positive mental health that goes beyond the fact that you’re not depressed. What that is is still a mystery. But when we understand the set of processes involved, we will have much more insight into how health works.”

Kubzansky is at the forefront of such research. In a 2007 study that followed more than 6, 000 men and women aged 25 to 74 for 20 years, for example, she found that emotional vitality—a sense of enthusiasm, of hopefulness, of engagement in life, and the ability to face life’s stresses with emotional balance—appears to reduce the risk of coronary heart disease. The protective effect was distinct and measurable, even when taking into account such wholesome behaviors as not smoking and regular exercise.