Optimism: The Cambridge English Dictionary defines optimism as “the tendency to be hopeful and to emphasize the good part in a situation rather than the bad, or the feeling that in the future good things are more likely to happen than bad things.”

In numerous medical studies, an optimistic outlook is strongly associated with better health outcomes: from helping people recover from illness/surgery, to boosting the immune system, to lower rates of cardiovascular disease, to significantly improving overall health and longevity in follow-up periods of 15–40 years.

Clinical investigations of optimism’s impact on health typically use two systems of measurement 1) dispositional optimism and 2) explanatory style.

Dispositional optimism depends on positive expectations for one’s future in diverse areas, and many researchers use the 12-item Life Orientation Test to measure it.

Explanatory style is based on how a person explains good or bad news. Optimists, unlike pessimists, do not assume blame for negative events; they assume good things will last and are more confident that positive developments will spill over into many areas of their life. Researchers often use either the Attributional Style Questionnaire or the Content Analysis of Verbatim Explanations method to evaluate optimism based on explanatory style.

Research Spotlight

The databases often return hundreds of medical studies for a single wellness approach. This section summarizes a sampling of a few studies – providing just a taste of the available research. These Spotlights were not selected because they are the most favorable or the most recent, but to provide you an introduction to the more extensive research you’ll uncover searching the four databases found in the “Research” section of this site.

  • Optimists Have Much Lower Risk of Disease and Mortality Rates
    A major 2019 analysis of 15 studies (229,391 participants) found that people ranking high in optimism were much less likely to have a heart attack or other cardiovascular event and had a lower mortality rate from any cause than did pessimistic participants. Across all data, there was a strong relationship between optimism and a lower risk of disease, with optimists having a 35 percent lower risk of cardiovascular events—and a 14 percent lower risk of premature deaths—than pessimists.
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  • Optimism Associated with Strong Immune Response
    A University of Kentucky study (2010) that tracked changes in optimism and immune response among law students found that as students became more optimistic, they showed stronger cell-mediated immunity, the flood of immune cells that respond to an invasion by foreign viruses or bacteria. When optimism dropped, so did cell-mediated immunity. Researchers concluded that positive thoughts affect immune systems, even in healthy people.
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  • Optimism Reduces Heart Disease Risk
    A large Harvard University review (200 studies, 2012) on cardiovascular risk and emotional state found that the traits of optimism and hope, and higher levels of happiness and satisfaction with one’s life, were linked with significant reductions in risk of heart disease and stroke.
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  • Optimists More Likely to Live to 85+
    A 2019 Boston University and Harvard T.H. Chan School of Public Health study, which followed 69,744 women over 10 years and 1,429 men over 30 years, found that people with greater optimism are more likely to achieve “exceptional longevity”—living to age 85 or older. Among the most optimistic study participants, the women had a 50 percent greater chance and the men a 70 percent greater chance of surviving to age 85. 
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  • Optimism Protects Against the Inflammatory Effects of Stress
    A University of College London (2009) double-blind placebo-controlled study found a strong positive association between optimism and antibody responses, concluding that optimism counteracts stress-induced increases in inflammation and boosts the adjuvant effects of acute stress. 
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  • Optimists More Likely to Engage in Healthy Behaviors
    A 2018 study (Chapman University, Harvard T.H. Chan School of Public Health) found that optimistic individuals were more likely to engage in three healthier behaviors: increasing physical activity, embracing a healthier diet, and refraining from smoking.
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