Rising Social Stress May Be Linked To Declining Global Population

An environmental health scientist at the University of Massachusetts Amherst has developed a “neglected hypothesis” to help explain the expected global population decline from 2064: social stress.

The stress of social media and other largely empty or overwhelming social interactions can lead or contribute to changes in behavior and reproductive physiology, suggests Alexander Suvorov, associate professor in the School of Public Health and Sciences. health UMass Amherst.

In a review article published in the journal Endocrinology, it examines various theories surrounding the previous decline in human population as models predict a “remarkable” decline from 9.7 billion people in 2064 to 8.8 billion by 2100. Populations in some countries have already reached peak and are expected to decline by 50% by the end of the century.

“A unique feature of the coming population decline is that it is almost exclusively caused by decreased reproduction, rather than by factors that increase death rates (wars, epidemics, famine, extreme weather conditions, predators and catastrophic events), ”he wrote.

Suvorov sketches an hypothesis that relates reproductive trends to population densities, proposing that density reflects the quality and frequency of social interactions.

“The increase in the number of populations contributes to less meaningful social interactions, social withdrawal and chronic stress, which subsequently suppress reproduction,” the manuscript states.

Over the past 50 years, a 50% decrease in sperm count has occurred. Stress is known to suppress sperm count, ovulation and sexual activity, Suvorov notes. While changes in reproductive physiology are generally attributed to the effects of endocrine disrupting pollutants, Suvorov believes this is not the only factor.

Numerous wildlife and laboratory studies have shown that population peaks are always followed by increased stress and suppressed reproduction. When a high population density is reached, something happens in the neuroendocrine system that suppresses reproduction. The same mechanisms that occur in wildlife may also be at work in humans. “

Alexander Suvorov, Associate Professor, UMass Amherst School of Public Health and Health Sciences

Suvorov points to several changes in reproductive behavior that are contributing to the population decline, including people with fewer children and waiting longer to start a family or choosing not to have children. But he says biological changes are probably happening too. More research is needed, he says, such as studies to determine the levels of cortisol in human blood, an important measure of stress.

“A better understanding of the causal chain involved in the suppression of reproduction by factors related to population density can help develop interventions to treat infertility and other reproductive problems,” writes Suvorov.

He hopes his hypothesis offers an attractive area of ​​research that scientists from different fields will be interested in exploring.

“The purpose of this article is to draw attention to a completely ignored hypothesis – and this hypothesis raises more questions than it answers,” Suvorov said. “I hope this will spark the interest of people from very different fields and that after further study we will have a much better idea of ​​how much population density is related to social stress and how social stress is. related to reproduction, and what we can do about it. “

A common sense place to start, he suggests: “Get out of social media.”