Anthropologists have revealed how megacities are damaging our health

Modern urban life is moving further and further away from the conditions in which humans evolved as a species.

Because of this, there is a growing gap between what our bodies are adapted to and how we live now, argue evolutionary anthropologists Colin Shaw from the University of Zurich and Daniel Longman from Loughborough University. They described their hypothesis in a review in the journal Biological Reviews.

For hundreds of thousands of years, humans have lived as hunter-gatherers: moving a lot, experiencing short-term, "acute" stress, and constantly interacting with the natural environment. Industrialisation radically changed the near-environment in just a few centuries: noise, light and air pollution, microplastics, pesticides, excess artificial light, processed foods and sedentary lifestyles were added.

"In our ancestral environment, we were well adapted to acute stress - to run away from a predator or fight back," explains Colin Shaw. - A lion would appear from time to time, you had to be ready to defend yourself or flee. The important thing is that the lion then disappeared."

Today's stimuli - traffic jams, deadlines, notifications, social media, constant noise - trigger the same biological mechanisms, but without the "decoupling" and recovery.

"Our body reacts as if each of these factors is a new lion," adds Daniel Longman. - The stress system is switched on again and again, but there is almost no phase of full rest and nullification."

From an evolutionary perspective, the success of a species is determined by its survival and ability to reproduce. According to the authors, the industrialised environment is hitting both at once. They point to the global decline in fertility and the rise in chronic inflammatory diseases, including autoimmune diseases, as signs of the biological price paid by the organism for living in a man-made world.

A separate example is the decline in sperm quality recorded since the 1950s: sperm count and motility are falling. Shaw attributes this to exposure to pesticides and herbicides in food, as well as microplastics.

"We live in a strange paradox: on the one hand, industrialisation has given many people on the planet unprecedented levels of comfort, nutrition and medical care," says Shaw. - On the other hand, many of the advances of the industrialised world are damaging our immune, cognitive, physical and reproductive functions."

Biological evolution is too slow to keep up with such environmental changes, scientists emphasise. Genetic adaptations take tens to hundreds of thousands of years, while cities, technologies and habits change in a matter of generations. Therefore, in their opinion, it is impossible to count on "natural adaptation" of the organism to the industrial world - cultural and infrastructural solutions are required.

One of the key ideas is to reconsider the attitude towards nature as an important factor of health. This means protecting and restoring green areas that resemble natural landscapes as much as possible, where people can visit more often, not just see them in pictures. Another is to design cities in new ways that take human physiology into account: noise levels, lighting, air quality, green spaces and spaces for movement and recreation.

"Our research helps us understand which stimuli have the strongest effect on, for example, blood pressure, heart rate or immune system health," explains Shaw. - This information is important to pass on to decision makers in urban planning and policy."

To narrow the evolutionary "gap," scientists say, society needs to do two things at the same time: getting cities "right" and getting people back in more contact with nature - from daily walks in the park to protecting entire ecosystems,