Verified by 
"Super Red" by Trevor Mikula
A study released on July 23, 2013 found that optimists have a better biological response to stress than pessimists. Researchers at Concordia University's Department of Psychology have found that “the stress hormone” cortisol tends to be more stable in people with a positive outlook.
I have written numerous Psychology Today blogs on the health detriments of chronic elevated levels of cortisol and the power of positive thinking to reduce stress and improve well-being. This new study offers more proof that our explanatory style makes all the difference in our mental and physical health.
Each of us has the free will to be an optimist or a pessimist. The daily choices of mindset and behavior that we make create biological changes throughout our bodies that have long lasting ramifications.
Participants in the Concordia University study reported the level of stress they perceived in their daily lives. The subjects self-identifed along a spectrum based on optimism and pessimism. Each person's stress levels were then measured against their own average and self-identified along a continuum. Measuring the stress levels against participants' own average provided a real-world picture of how individuals handle stress because individuals can become accustomed to the typical amount of stress in their lives.
Joelle Jobin, a PhD candidate in clinical psychology who co-authored the study says "for some people, going to the grocery store on a Saturday morning can be very stressful, so that's why we asked people how often they felt stressed or overwhelmed during the day and compared people to their own averages, then analyzed their responses by looking at the stress levels over many days."
Jobin found that pessimists tend to have a higher stress baseline than optimists. Pessimists generally had trouble regulating their sympathetic nervous system when they go through stressful experiences. The inability to look on the bright side causes cortisol to stay constantly elevated. "On days where they experience higher than average stress, that's when we see that the pessimists' stress response is much elevated, and they have trouble bringing their cortisol levels back down. Optimists, by contrast, were protected in these circumstances," says Jobin.
The vagus nerve and healthy vagal tone are directly linked to balancing the ‘fight or flight’ response of our sympathetic nervous system (which is linked to chronic high levels of cortisol) with the ‘rest and digest’ and 'tend and befriend' function of our parasympathetic nervous system. In addition to making a conscious effort to be more optimistic, you can also make lifestyle choices that will activate a parasympathetic response, slow your physiology down, and improve your stress response.
For more practical advice on how to stabilize your cortisol levels please check out my Psychology Today blogs: “The Neurobiology of Grace Under Pressure”, “How Does Meditation Lower Anxiety at a Neural Level?" and "Social Connectivity Drives the Engine of Well-Being."
Conclusion: The Yin-Yang of Cortisol Levels
Like most hormones in our bodies, cortisol is a complex hormone with many functions. Although "the stress hormone" cortisol is linked to many health detriments — it is also our "get up and do things hormone," according to Jobin. Just like we have ‘eustress’ (good stress) and ‘distress’ (bad stress), we need cortisol to stimulate our sympathetic nervous system and kickstart our bodies into action.
While the study generally confirmed the researchers' hypotheses about the relation between optimism and stress, one unexpected finding was that optimists who had high pressure jobs or more stressful lives actually secreted higher cortisol levels than expected shortly after getting up in the morning. Cortisol levels typically peak just after we wake up and tend to decline through the day in people with a healthy adaptation to stress.
Joelle Jobin believes there are several possible explanations for the ebb and flow of cortisol but notes that the findings clarify the difficulty of classifying any complex hormone as good or bad. Jobin concludes, "The problem with cortisol is that we call it "the stress hormone," but it's also our 'get up and do things' hormone, so we may secrete more if engaged and focused on what's happening."
