Have humans peaked when it comes to life span?

An unprecedented study has found that humans have biological limitations, and that human-caused environmental changes may play a role in preventing these limits from being reached. The analysis suggests that humans have likely arrived at their maximum limits for height, physical performance, and lifespan.

For the investigation, an interdisciplinary team of experts from across France have accounted for 120 years worth of data while considering the effects of both genetic and environmental circumstances. The findings of the study indicate that humans are now the tallest they can become, have the longest life expectancies, and the most physical abilities they will ever have.  

“These traits no longer increase, despite further continuous nutritional, medical, and scientific progress,” explained Professor Jean-François Toussaint from Paris Descartes University. “This suggests that modern societies have allowed our species to reach its limits. We are the first generation to become aware of this.”

The researchers found that there will be notable a shift in the proportion of the global population who reach the previously recorded maximum limits. From here on out, less athletic records will be broken and people will meet – yet not exceed – today’s highest life expectancy.

When the researchers considered how both environmental and genetic limitations combined may affect the ability for us to reach our upper limits, human-caused environmental changes were identified as a key contributor.

“This will be one of the biggest challenges of this century as the added pressure from anthropogenic activities will be responsible for damaging effects on human health and the environment,” said Professor Toussaint. “The current declines in human capacities we can see today are a sign that environmental changes, including climate, are already contributing to the increasing constraints we now have to consider.”

“Observing decreasing tendencies may provide an early signal that something has changed but not for the better,” he explained. “Human height has decreased in the last decade in some African countries; this suggests some societies are no longer able to provide sufficient nutrition for each of their children and maintain the health of their younger inhabitants.”

The researchers hope the findings of this study may have some positive consequences by encouraging policymakers to focus on strategies that could improve quality of life and maximize the number of people who reach their biological potential.

“Now that we know the limits of the human species, this can act as a clear goal for nations to ensure that human capacities reach their highest possible values for most of the population,” said Professor Toussaint. “With escalating environmental constraints, this may cost increasingly more energy and investment in order to balance the rising ecosystem pressures. However, if successful, we then should observe an incremental rise in mean values of height, lifespan and most human biomarkers.”

The research is published in Frontiers in Physiology.

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By Chrissy Sexton, Earth.com Staff Writer