Many poets, philosophers, and thinkers throughout history have recognized the intimate link between physical and mental health. The ancient Roman poet Juvenal once declared "A healthy mind in a healthy body". However, until relatively recently, most psychological research has focused on the link between psychological difficulties (e.g., anxiety, depression) and physical health.
But things are changing. Over the past few decades, a growing number of studies demonstrate that merely alleviating anxiety and stress don't necessarily lead to better life outcomes. Positive characteristics, such as optimism, vitality, meaning, and subjective life satisfaction are immensely important in their own right. The related fields of positive psychology and health psychology focus on rigorous scientific investigations of how people adapt to life's inevitable challenges, and how that is related (or even leads to) a better quality of life. This process of resilience across life is the idea of thriving, successful aging, or flourishing.
When individuals are confronted with challenge, they may succumb or they may respond in one of three ways: They may survive (continuing to function, but in an impaired fashion), recover (return to previous levels of emotional, social and psychological functioning), or thrive (to go beyond the prior baseline, to grow and flourish). Through the interactive process of confronting and coping with challenges, a transformation occurs. As Virginia O'Leary puts it,
"The potential theoretical, empirical and policy significance of the proposed paradigm shift from illness to health, from vulnerability to thriving, from deficit to protection and beyond ought not be underestimated. The precedent for this paradigm shift is growing in the scientific literature."
One of the most important coping mechanisms that has been discovered is optimism. According to the father of positive psychology, Martin Seligman, our "explanatory style," or the way in which we interpret our setbacks, is learned early in our lives and influences whether we rise above failure or accept it. Those with an optimistic explanatory style have positive expectancies for positive outcomes in the future ("In uncertain times, I usually expect the best").
This conception is important because optimism is particularly associated with positive immunological functioning and health. A 2012 review conducted by Julia Boehm and Laura Kubzansky concluded that in healthy populations, "optimism and vitality are consistently associated with reduced risk of incident cardiovascular events." In fact, across both healthy and patient populations, optimism was "the most reliably associated with a reduced risk of cardiac events."*
Since that 2012 review, two additional studies have come out that further point to the robustness of this association. Rosalba Hernandez and colleagues focused on the American Heart Association's definition of cardiovascular disease (CVD), which involves consideration of 7 metrics grouped into two categories: health behaviors (diet, smoking, physical activity, BMI) and health factors (blood pressure, blood sugar, total cholestrol). This was the first study to consider the association between optimism and CVH as defined by the American Heart Association, and this was also the first study to utilize a large sample of ethnically/racially diverse sample of adults.
Using data collected from 5,134 adults aged 52-84 over an 11 year period, they found a significant association between optimism and cardiovascular health (CVH), with the most optimistic people showing twice the odds of having ideal CVH profiles. The association remained significant even after controlling for socio-demographic variables (i.e., age, sex, race/ethnicity, marital status, education, income, and insurance status) and measures of psychological ill-being (e.g., depression), again supporting the notion that a lack of ill-being doesn't necessarily indicate the presence of thriving.
Additional analysis found that the association between optimism and CVH was particularly driven by diet, physical activity, BMI, smoking, blood sugar and total cholesterol. Interestingly, they also found that a greater proportion of African-American and Hispanic/Latino participants were represented at the highest levels of optimism as compared to the lowest levels of optimism.
Another recent study conducted by Penn psychologist Johannes Eichstaedt and his colleagues at the World Well-Being Project used language expressed on Twitter to predict mortality from atherosclerotic heart disease (AHD) at the community level. Here is the Twitter language that indicated a decreased risk of county-level AHD mortality:
As you can see, language indicating optimism and resilience ("opportunity", "possibilities", "dreams", "overcome") significantly predicted the rates of mortality due to heart disease within a particular community. In contrast, here are Twitter topics that were related to an increased risk of county-level AHD mortality (note that this figure may be NSFW!):
Note that these findings do not necessarily mean that if you, personally, are angry on Twitter, that you have increased risk for heart disease. These findings may hold up at the individual level of analysis (and that analysis is currently being conducted), but that's not what this figure means. Rather, these findings suggest that the psychological states of communities are associated with rates of heart disease within those communities. Communities that are hotbeds of anger are also hotbeds of decreased physical health. This research offers 21st century technological support for the ideas of some of the greatest thinkers in history about the mind-body connection.
Twitter language may even be a better predictor of heart disease in a community than more traditional measures of health. Here is a comparison of the predictions of AHD mortality with other variables that are commonly investigated:
As you can see, Twitter predicted AHD mortality above and beyond traditional risk factors! In fact, for all combinations of sets of traditional predictors, adding Twitter language significantly improved prediction, whereas adding traditional sets of predictors to Twitter did not significantly improve prediction.
Finally, let's take a look at the CDC-reported AHD mortality averages across 2009 and 2010 and the Twitter-predicted mortality in the northeastern U.S. (the left shows estimates from the Centers for Disease Control and Prevention and the right shows the estimates generated through Twitter language):
Interestingly, there is a high degree of agreement between CDC-reported mortality averages and the data gleaned from language used on Twitter. Analyzing "big data" across social networking platforms (Twitter, Facebook, etc.) is clearly a very promising technique for predicting positive and negative health that can complement other methods used in epidemiology.
Given that the typical Twitter user is younger (average age = 31 years) than the typical person at risk for heart disease, why would Twitter language track heart-disease mortality? As the researchers put it, "the people tweeting are not the people dying."
The researchers suggest that the tweets may reflect characteristics of their community, reflecting a shared economic, physical, and psychological environment. "The language of Twitter may be a window into the aggregated and powerful effects of the community context," they note.
WHAT'S GOING ON?
As this review (which includes 10 studies) suggests, the link between optimism and a healthy heart is real and robust. But this is just an association. This research doesn't mean that optimism causes a healthy heart. It's possible that being healthy causes people to be more optimistic. Or even another variable might be at play here that causes both optimism and a healthy heart to be related. While there is increasing evidence that high well-being does cause better health and longevity, we definitely need more research that follows people up over a long period of time and looks at the precise mechanisms that cause these factors to be related.
One possibility is that optimists employ more adaptive coping skills when faced with adversity. Indeed, there is research suggesting that optimists are more likely to engage in "active problem-focused coping" and cope more adaptively with stress by giving a more positive interpretation to stressful events. Optimistic strategies predict a greater likelihood of engaging in healthy behaviors (tobacco avoidance and moderate alcohol use) and are correlated with more positive health profiles. So the research does hint at the idea that optimism sets off a chain of behaviors and practices that lead to a healthy body. But there certainly still needs to be more research to know for sure what's going on. The association is most likely bidirectional (optimism and health feed off each other).
It's also unclear whether there's such a thing as too much optimism. Research suggests that "positive emotion persistence" can be a marker of emotion dysfunction. Additionally, Joseph Forgas found that a negative mood (to a moderate degree) was associated with a variety of cognitive, motivational, and interpersonal benefits, including improved memory, perseverance on a demanding cognitive task, increased fairness, increased persuasion, reduced gullibility and reduced stereotyping. Too much positive dreaming can also lead to less action. Gabriele Oettingen has found across multiple studies that too much "indulging" in positive fantasies, without also being grounded in reality, makes goal attainment less likely.
The takeaway from these studies is that all of our mindsets, emotions and moods are adaptive in some contexts but not in others. The key is temperance and balance, and being resilient and flexible depending on the circumstances. Optimism doesn't mean blind optimism. As Todd Kashdan and Robert Biswas-Diener point out in their delightful book "The Upside of Your Dark Side," the key is cultivating your "whole self", not just your "good" self.
Nevertheless, this emerging research does suggest that optimism is a key aspect of being whole, and I am optimistic that further research will increase our understanding of how optimistic coping strategies influence our health, and how our health reciprocally influences our mind. Heck, even if I'm wrong, and the research shows that pessimists (or even, gosh forbid, realists) rule the world, at least my optimism might still increase my cardiovascular health!
© 2015 Scott Barry Kaufman, All Rights Reserved
* All 8 of these studies found that indicators of optimism and vitality ("I feel alive and vital") were associated with a reduced risk of cardiovascular disease among non-patient populations:  Kubzansky et al., 2001  L.R. Martin et al., 2002  Giltay et al., 2004  Giltay et al., 2006  Kubzansky & Thurston, 2007  Richman et al., 2009  Tindle et al., 2009  Boehm et al., 2011.
image credit: istockphoto