Humans may be biologically unequipped to handle the relentless pace and pressures of modern life, a new study suggests, with chronic stress emerging as a significant evolutionary mismatch in the industrialized world.
The peer-reviewed study, published in Biological Reviews by evolutionary anthropologists Colin Shaw of the University of Zurich and Daniel Longman of Loughborough University, argues that rapid technological and environmental changes have outpaced the slow process of human evolution, which has compromised our mental and physical health and reproduction.
“In our ancestral environments, we were well adapted to deal with acute stress to evade or confront predators,” Shaw said in the study’s accompanying release.
“The lion would come around occasionally, and you had to be ready to defend yourself—or run. The key is that the lion goes away again.”
Fight or Flight
Today’s stressors—like traffic, deadlines, noise and social media—may feel routine, but they trigger the same fight-or-flight systems as predatory threats did in the past, Longman noted.
“Whether it’s a difficult discussion with your boss or traffic noise, your stress response system is still the same as if you were facing lion after lion,” he said.
“As a result, you have a very powerful response from your nervous system, but no recovery.”
Why it Matters
According to the researchers, the mismatch between modern lifestyles and ancestral biology may be harming evolutionary fitness—defined as the ability to survive and reproduce.
Shaw and Longman point to declining global fertility, chronic inflammation and reduced sperm counts as symptoms of stress-induced biological strain.
The consequences are wide-reaching. In an email to Newsweek, Longman said his biggest takeaway from the study was, “how profound and pervasive,” the mismatch seems to be.
“It’s not a single health issue,” he said, “It spans core systems. And what surprised me most was the strength and consistency of the evidence: physiology, epidemiology and evolutionary theory all point to the same conclusion.”
What to Know
The researchers found that key stress responses—intended for short-term emergencies—are now constantly activated by modern living.
This persistent activation may impair everything from immune system performance to memory and hormonal balance.
Notably, sperm count and motility have dropped significantly since the 1950s, trends some studies link to environmental pollutants like microplastics and pesticides.
What People Are Saying
Longman said the mismatch, “isn’t just persisting, it’s potentially expanding,” citing the Great Acceleration of the mid-20th century as, “the real turning point”.
“Since then, urbanization, pollution, chemical exposure, microplastic accumulation, artificial light and noise have all increased at a pace far beyond what human physiology can realistically adapt to,” he told Newsweek.
“On top of these environmental shifts, the last two decades have added a new dimension: Constant digital connectivity, social media, 24/7 information flow and, more recently, [artificial intelligence]-mediated interactions.
“Our stress-response systems evolved for short bursts of acute threat and not for continuous notifications and the absence of genuine psychological ‘off-time.’ In that sense, the digital environment amplifies the mismatch created by industrialization.”
What’s Next
The researchers advocate for designing cities and workplaces that reflect human physiological needs.
Longman stressed, however, that cities are not the enemy.
“The point is that many urban environments currently lack the features our biology depends on and introduce novel stressors that we’re not adapted to and are harmful to our biology,” he said.
Longman also noted that their study doesn’t come with a quick fix.
“This isn’t just a ‘nice to have’ conversation about being more in nature,” he said.
“According to our analysis, exposure to natural environments is biologically necessary.”
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