Here are all the ways living in cities is horrible for you

More than half of the world’s population lives in cities, and urban life is taking a toll on our health and well-being.

By 2050, experts estimate that as much as 70% of humanity will reside in cities. And the traffic, the noise, the pollution — it all adds up.

From making us feel more stressed to polluting our bodies, here are some of the many ways city life is slowly making us miserable.

City life literally makes us crazy.

Bad news, urbanites: Studies suggest that city populations have higher rates of mental illness than rural ones. In fact, urbanites have a 21% increased risk of developing an anxiety disorder and a 39% increased risk of having a mood disorder compared with residents of rural areas, according to a 2010 study.

Why do city dwellers have higher rates of mental illness? The answer could come down to how their brains process stress. For a 2011 study, researchers scanned the brains of urbanites and found increased activity in two brain regions: the amygdala, involved in processing emotions, and the perigenual anterior cingulate cortex, involved in processing stress.

Everyone's always rushing.

City life happens, quite literally, at a faster pace.

In one older study from 1999, researchers measured 3 things across 31 countries to get an idea of what they called 'the pace of life' in those places:

  1. How fast people walked in downtown areas
  2. How long it took postal workers to complete a simple request
  3. The accuracy of public clocks

Life as they measured it was fastest in Japan and Western Europe and slowest in undeveloped countries. The pace was also faster in colder climates, economically productive countries, and in 'individualistic cultures,' the researchers reported.

The air is polluting our bodies.

Whether you live in Rome, Amsterdam, or another highly populated area, city life may be jeopardizing your physical health. For a 2013 study, researchers measured the effects of long-term exposure to fine particulate matter (PM) and nitrogen dioxide gas (NO2) -- two common environmental pollutants -- on a group of more than a million Roman residents over 9 years.

The researchers found a link between the levels of these pollutants and the chances of death, primarily from coronary artery diseases, followed by other heart diseases and lung cancer. Another study from the same year of more than 7 million Dutch people followed for 7 years found a similar link between pollution and mortality.

It's making our immune systems act up.

A hospital doctor wears a mask to protect herself from Swine flu.

If you live in an urban area you may be more susceptible to allergies than if you live in a rural area, some studies suggest.

In one recent study of about 1,300 elderly people living in urban, semiurban, and rural areas, researchers gave participants a skin prick test -- they dropped a solution containing one of nine common allergens on each person's forearm or back, and gently scratched the skin to allow the allergen to seep in. Those from more urban areas had a stronger allergic reaction to the test than those from rural areas.

The constant light mess with our sleep.

'Bright lights, big city' -- the title of this classic novel -- is an apt description of urban life.

A 2014 study comparing urban and rural populations found that city dwellers were more suspectible to social jet lag, a shift in sleep schedule that can happen when there's a gap between the hours you keep on certain days, like the weekday, and the hours you keep on other days, like the weekend. In some cases, studies show, this jet lag can be linked with a higher risk of obesity and some chronic diseases like diabetes.

It's full of uncaring crowds.

Even though you may never be alone in a city, a group of strangers may not offer the support you need. Researchers became interested in the so-called 'bystander effect' after the 1964 murder of Kitty Genovese, a young woman who was stabbed to death while dozens of neighbours supposedly stood by and watched.

While that explanation of the crime has since been called into question, other studies lend some creedence to the idea that people are less caring in large groups. A seminal 1968 study, for example, which put young men in a smoke-filled room either alone or in groups of two or three people found that the men were much less likely to report the smoke when they were in groups than when they were alone.

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