(CNN) Being pessimistic may keep your heart from being broken when a best-case scenario fails to come to pass, but there are some real health benefits to seeing the glass as half full.
Optimism -- having favorable expectations about the future -- may be good for your heart and overall quality of life. People who are more optimistic than pessimistic tend to live longer, have better cardiovascular health, get a higher quality of sleep and have improved immune systems, studies suggest.
There are some research-based daily practices that might help you become more optimistic, said Nancy Sin, a postdoctoral fellow at Pennsylvania State University's Center for Healthy Aging and Department of Biobehavioral Health.
"I think that it probably is achievable if you have concrete ways of trying to increase optimism," Sin said. "There are exercises that people can do to try to practice optimistic thinking, but in terms of how long-lasting these exercises are or whether they might result in improvements in health, I think the jury is still out."
An exercise in which you imagine your best possible self, living your best possible life, may improve levels of optimism, suggests a small study published in the Journal of Behavior Therapy and Experimental Psychiatry in 2011.
The Netherlands-based study involved 54 native Dutch-speaking adults, 18 to 43, who were divided into two groups.
One group was asked to think of and write down all best possible scenarios for their life in terms of personal, relational and professional domains. The other thought about and wrote down the activities that had taken place in their lives during the past 24 hours.
All participants were asked to put their thoughts into a detailed and coherent story.
Then, in both groups, participants were instructed to imagine these stories playing out in a five-minute imagery exercise. The participants repeated these exercises once a day at home, for about five minutes, over a two-week period.
All participants also completed questionnaires intended to gauge their levels of optimism before the experiment, one week into the experiment and then after the two-week period.
The researchers found that the daily exercise of imagining your best possible self for two weeks resulted in increases in optimism, according to the questionnaires, after one week and the two-week period.
"There's this range of things we can do" to improve optimism, said Eric Kim, a research fellow at Harvard T.H. Chan School of Public Health. He was not involved in the study.
"There are these paper and pencil exercises that show small effects on optimism, and another one is actually writing things that you're grateful for," he said. "In randomized studies, if you do that for seven days, that's been shown to increase optimism a little bit."
Writing in a journal about what you are grateful for was linked to greater feelings of optimism in a 2003 study published in the Journal of Personality and Social Psychology.
One experiment in the study involved 192 undergraduate students who were divided into three groups. Each group wrote 10 weekly reports.
One group wrote about what they were grateful for over the past week, another group wrote about five hassles that occurred in the week, and the third group wrote about events or circumstances that affected them in the past week.
In addition to their weekly reports, the participants were asked to rate their overall mood, physical health, reactions to social support received, time spent exercising, life satisfaction and expectations for the upcoming week.
Participants in the gratitude group reported higher satisfaction with their lives as a whole and were more optimistic about the upcoming week than participants in the other two groups, the researchers found.
A separate study showed that keeping a journal in which you write down your own acts of kindness is linked to increased optimism, Kim said. The study was published in the Journal of Happiness Studies in 2006.
One experiment in the study involved 119 female undergraduate students. They were asked to keep a daily journal and track any acts of kindness they performed for one week.
The students also completed a questionnaire in which they rated their personal feelings of happiness one month before and after the weeklong journaling.
The researchers found that the students' subjective happiness seemed to increase after the one-week experiment.
Although certain practices may shift your thinking patterns to be more optimistic, they won't completely transform who you are overnight, Kim said.
"The thing I'm uncomfortable with seeing is that people think we can just completely change our levels of optimism just out of our sheer will and practice, but there's this really strong environmental factor that also impacts us," Kim said.
"People might be optimistic for a variety of reasons. For example, twin studies show that about 25% of optimism is heritable, which does mean that some of it can be controlled by thinking patterns and things that we do by ourselves, but also a lot of it might be due to social and structural factors," he said.
For instance, how much warmth and attention your parents gave you during childhood have been associated with levels of optimism later in life, Kim said.
Socioeconomic status is also linked to optimism, with a lower status associated with viewing the future more negatively, according to a 2009 study published in the International Journal of Behavioral Medicine.
"So, even when we look within sociodemographic groups, like different levels of wealth or different levels of education, we see that there is a larger range of optimism within there," he said.
Whether it comes naturally or not, a healthy degree of optimism still can be beneficial, Sin said.
"For the new year, I know a lot of people tend to set health goals, and I think that's where optimism can be really important, because if you are more optimistic or if you just generally feel that you can achieve these goals, then you might be more likely to be successful," Sin said.
"Part of the way that optimism operates is that it motivates people to tap into their social networks, and it helps people to figure out how to cope with setbacks and challenges," she said.