CogniFit's Science blog: City Life May Harm Your Brain

City Life May Harm Your Brain

The past century has been marked by a fundamental change not only in how the human beings live, but also and most importantly where we live.

Through most of the history, the human population has lived a rural lifestyle, very much dependent on agriculture. The urbanization of the world has been an increasing trend since very long ago, and an explosion since the industrial revolution until our days.

In 1800, only a tiny part of the population (3%) lived in urban areas. By 1950, that number had been multiplied by 10. Today, more than half of the world population lives in cities, and this number is expected to rise to 70% as currently developing nations reach a higher income level.

The urbanization brings however new challenges to the human kind, and especially to the brain health. In an international study published in the journal Nature, researchers at University of Heidelberg and the Douglas Mental Health University Institute at McGill University report that people who live or were raised in cities show distinct differences in brain activity when compared to country people.

The main findings of this study are especially interesting for the population in developed nations, where over 70% of the people already live in cities – it indicates that city dwellers have a higher risk of mental illness (anxiety, mood disorders and schizophrenia are significantly more common, the latter having the double of the incidence), lower tolerance to stress. Those effects are increased the bigger the city is, and the longer they have lived there.

Although social stress has been speculated in the past as having an effect on the brain, this study is the first to investigate the mechanism that links cities to mental illness via social stress. The study was conducted with a first group of 32 college students. The initial assessment of heart rate, blood pressure and stress-hormone levels indicated there were no significant differences between country and city kids. The test phase itself was designed to be highly socially stressful, and in this first test city brains had a disproportional response to social stress. The test was repeated twice more with a total of 70 students. The initial pattern was maintained, even when other key variables such as age, education, income, family status, mood, were taken into account.

What does this mean for all of us living in a city? These findings show the importance of a healthy lifestyle and brain fitness for everyone living in cities. This means in other words, keeping things in balance, avoid stress situations, invest in the quality of life, and most importantly follow Dr. Stephen Covey’s 7th habit of highly effective people – sharpen the saw! Preserving you and your brain is your best defense.