Humans, alongside their primate cousins, are far more likely than any other member of the animal kingdom to get stress-related illness. But why? According to Robert Sapolsky, a neuroscientist at Stanford University, it’s a result of their high intelligence, social nature and having a lot of spare time on their hands.
In particular, Sapolsky has dedicated large swathes of his career to studying baboons in Kenya. Like humans, they have complex emotional lives and relatively stress-free lives. He said, “If you live in a baboon troop in the Serengeti, you only have to work three hours a day for your calories, and predators don't mess with you much. What that means is you've got nine hours of free time every day to devote to generating psychological stress toward other animals in your troop...They're just like us: They're not getting done in by predators and famines, they're getting done in by each other (Stanford University: 2007).”
But how? Stress responses are common to all vertebrates via the release of hormones such as adrenaline and glucocorticoids, which immediately increase heart rate and energy levels. Although effective in helping animals escape from short term, life-threatening stressors such as being chased by a lion, non-life threatening stressors also trigger these hormones which, over time, has negative consequences on health, including an increased risk of diabetes, high blood pressure, gastrointestinal disorders, immune dysfunctions, impaired brain function, and more.
Although human intelligence has undoubtedly solved a lot of previously fatal problems, such as being able to grow food to prevent famine, or protect ourselves from predators, over time our intelligence had led to the creation of more abstract problems that although are not immediately life-threatening, provide a more pervasive, long term form of stress. These include constantly worrying about pleasing our bosses, paying off a 30-year mortgage and waiting in traffic.
Thus, the amalgamation of these long term stressors inherently leads to elevated levels of resting stress, which then contributes to a higher chance of stress-related illness- something that is especially noticeable when looking at what we’re now dying of. Whereas a century or so ago, the primary threats to human life included pneumonia, childbirth and the flu, nowadays illnesses such as heart disease, cancer, diabetes and Alzheimer’s disease take centre stage- all diseases either caused or made worse by stress (Goudarzi: 2007).
Sources
Stanford University: Science Daily
Goudarzi, Sara: Live Science