Biology

All downhill from here: Has the human race peaked?

All downhill from here: Has th...
A study of 120 years worth of historical data suggest we've reached the biological limits of height, life expectancy and sporting performance
A study of 120 years worth of historical data suggest we've reached the biological limits of height, life expectancy and sporting performance
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A study of 120 years worth of historical data suggest we've reached the biological limits of height, life expectancy and sporting performance
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A study of 120 years worth of historical data suggest we've reached the biological limits of height, life expectancy and sporting performance

Every four years, the world turns its attention to the Olympics to see competitors go "faster, higher, stronger." We tend to take this trajectory for granted, and average human height and life expectancy have played along by increasing significantly over the past two centuries. But the human body obviously has biological limits. A review of 120 years of historical records now suggests those limits may have already been reached – and if we aren't careful things could start going backwards.

The review carried out by a transdisciplinary research team from across France studied historical data on lifespan, sport and height collected since the nineteenth century. The goal was to gain a better understanding of how human physiology had progressed over the last 10 generations, and the team says the records suggest that these traits have plateaued and there are maximum limits that cannot be exceeded.

"These traits no longer increase, despite further continuous nutritional, medical, and scientific progress," says Professor Jean-François Toussaint from Paris Descartes University, France. "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 say that instead of the tallest humans getting taller, the fastest getting faster and the longest-living getting older, the best we can hope for is an increase in the proportion of the population reaching the existing limits for these traits. As a result, there would be more and more people living to the current highest life expectancy (around 85 to 95 years, with 115 to 125 years the limit for maximum longevity) and growing to maximum current heights (about 200 cm/6.5 ft), while fewer and fewer sporting records would be broken.

However, that's a best-case scenario and there could actually be a decline in life-expectancy, height and sporting performance due to a combination of genetic limitations and environmental factors, such as climate change. Prof. Toussaint points out that such a decline of human height has already occurred in some African countries due to a lack of nutrition available to children.

"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," predicts Prof. 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."

The researchers hope their findings will prompt policymakers to pursue strategies that will increase quality of life and allow the greatest proportion of the population possible to reach their maximum biological limits.

"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. 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. However, Prof. Toussaint warns the primary concern should be to arrest any future decline, saying, "The utmost challenge is now to maintain these indices at high levels."

The team's paper appears in the journal Frontiers in Physiology.

Source: Frontiers via EurekAlert

11 comments
VincentWolf
Yes man has stopped evolving for the most part because everyone today survives whether or not in nature they would have a chance to live at all. So if your feeble and would not have lived to pass on your genes today that doesn't apply to the human race. Survival of the fittest rules the natural world--it's what drives evolution. The idiots survive along with the rest of us so those genes are dumbing us down.
Daishi
The NYT has an interesting article on the 100m dash. In the first olympic 100m dash in 1986 the bronze time was 12.6 and now kids in highschool are hitting low 10's but the margin between good and best is much narrower today http://www.nytimes.com/interactive/2012/08/05/sports/olympics/the-100-meter-dash-one-race-every-medalist-ever.html
This is a scary subject of research though. The reality is that diversity allows people to bring different skills to the table and excel in different areas.
aksdad
Measuring the capacity or potential of humans simply by their physiological constraints is so self-evidently silly it makes me wonder what the point is. Does the physiological capacity of the Norman Borlaugs, Marie Curies and Thomas Edisons of the world matter more than their mental achievements and the technological innovations they fostered?
DaveLangley
I am unconvinced. This is from the same profession that said it was impossible to break the 4 minute mile barrier. Everything is impossible, until someone does it.
Jmnsnow
Also unimpressed as you do not mention the mutability possible to all living things. Yes, this present version of humanity may have peaked but what is occurring in the peripheries of human evolution? Where are the studies about those developments and how they are manifesting.
Douglas Bennett Rogers
People seem to be diverging. I see some people bench pressing 11000 lbs., while other people never pass 100 lbs. I suspect that the latter are working harder. Some people do 1000's of push ups while others don't get past 20. I think lack of vertical loading may be making people taller, and worse at sports..
NeilosBarross
The next generation is the first generation expected to have a lesser life expectancy than their parents
Tom Swift
Peaked? naw haven't even started, gene manipulation will "evolve" humans far beyond are current abilities.
highlandboy
Natural selection may remove specimens from the human gene pool, but where are the mutations that increase genetic diversity. Movies like X-men suggest that beneficial mutations should be on the increase. So far mutations all seem to be damage to existing working DNA. Our health systems support the “less fit” that would otherwise die out, but this is thought of as good. It allows the average life span to increase, but not bigger, better or stronger humans. Humans have a propensity to create/use substances that are detrimental to health (pesticides, cfcs, radiation), so is it any wonder we continue to be less healthy without sickness support systems.
JimFox
Interesting- agree entirely. The 4-minute mile argument is obviously specious, using a totally arbitrary target. Human biomechanics is pretty well understood as are its weakest links, which put an absolute limit on performance even if that limit is not completely definable Human performance is asymptotic, therefore has a definite limit.