The key to a long life may be your attitude.
Researchers at Harvard studied the impact of optimism on women's lifespans, finding that optimism was associated with greater longevity, such as living past age 90.
Lead study author Hayami Koga, a PhD candidate at the Harvard T.H. Chan School of Public Health in Boston, decided instead of studying risk factors, she wanted to look at positive assets and their impact on health and death.
"To begin to get at this, we wanted to consider the benefits of psychological resources, such as optimism, as possible new targets for promoting healthy aging," Koga said. "In a previous study, our research group found that optimism was linked to longevity, but we had looked in mostly white populations. We wanted to see if optimism could be a resource for healthy aging in other race and ethnic groups as well."
That distinction was important because in places like the United States, diverse populations have higher mortality rates than white populations. (Current life expectancy in the United States is 77 years.)
The new study found an association between optimism and long life across racial and ethnic groups.
For the study, the researchers analyzed data and survey responses from over 159,000 participants in the Women's Health Initiative, which included postmenopausal U.S. women aged 50 to 79 who enrolled in the 1990s and were followed for up to 26 years.
Expecting the Best
The research team used a psychological measure of optimism in which participants rate their feelings in statements such as, "In uncertain times, I usually expect the best."
The study found that the most optimistic quarter of women were likely to have a lifespan that was about 5% longer. They had a 10% greater likelihood of living past 90 when compared to the 25% of women who were the least optimistic.
"Scientists don't yet fully understand the pathways linking optimism to health and longevity. As we can't fully explain the relationship by these health-related behaviors, we think that there must be other things going on," Koga said.
She speculated that optimistic people may also be better at regulating their emotions during stressful situations and have more favorable biological profiles, such as lower levels of inflammation.
It's possible that optimistic people also have greater social support, Koga suggested.
"More research is needed to see if these processes help explain the relationship we see between optimism and longer lives," she added.
Koga said certain healthy lifestyle factors, such as healthy diet and regular exercise, accounted for about one-quarter of the relationship between optimism and longevity.
"There is some evidence suggesting that optimistic people are more likely to have goals and the confidence to reach them, so optimism may help cultivate and maintain healthier habits," Koga said. "People who are optimistic tend to also have healthier behaviors, and the relationship appears to be bidirectional — those who have healthier behaviors are also more optimistic."
The investigators found that optimism may be an important asset to consider when promoting health and longevity. Koga said studies have shown your optimism can be changed with active intervention, including some psychological approaches such as writing about positive experiences and gratitude.
"We tend to focus on the negative risk factors that affect our health, and this is certainly important," Koga said. "But it's also important to think about the positive things like optimism that can affect our health and to practice this to stay healthy and live longer, especially if we see that these benefits are seen across diverse groups."
The findings were published online recently in the Journal of the American Geriatrics Society.
Though genetics can influence temperament, life events can also have an impact on a person's optimism, said Dr. Ludmila De Faria, chair of the American Psychiatric Association's Committee on Women's Mental Health and an associate professor at the University of Florida.
Your Friends Matter
Feeling you have some control over events and trying to make changes even after adversity can be helpful, she said. Also, associating with positive people can help pull you through some rough patches.
De Faria cautioned that it isn't always possible for everyone to feel optimistic, and you shouldn't feel shame if you are not able to do that in your life circumstances.
"Sometimes it's just not their fault. It's not that they're lacking. For somebody who's trying to make ends meet and is working three jobs and cannot sleep well because they have to work all of these extended hours and are single parents and they have very limited amount of social interactions with other people, I don't want them to interpret this to say, well, on top of that, you should be working on reframing your reaction to adversity and maybe doing more yoga," De Faria said.
De Faria thinks that societal changes could allow people to become more optimistic and improve their mental and physical health. Supports that could help those at lower income levels could include access to health care, subsidized childcare and education that leads to jobs providing a sustainable income.
"Yes, it's wonderful that if you're more optimistic, you live longer, but how can we as a society facilitate you having healthier habits and being more optimistic?" she said.