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Fwd: Exercise and the Ever-Smarter Human Brain

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  • Dr. Lapin
    another suggestion that recess and physical activity might be more important to learning than sitting and working on the three R s. When will we prosecute the
    Message 1 of 1 , Dec 31, 2012
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      another suggestion that recess and physical activity might be more important to learning than sitting and working on the three "R"s.

      When will we prosecute the fossil fuel corporation directors and CEOs for genocide and crimes against humanity? Shouldn't we be talking about this?

      skype: dr.lapin

      Inicio del mensaje reenviado:

      De: Portside Moderator <moderator@...>
      Fecha: 30 de diciembre de 2012 10:52:29 p.m. PST
      Asunto: Exercise and the Ever-Smarter Human Brain
      Responder a: moderator@...

      Exercise and the Ever-Smarter Human Brain
      By Gretchen Reynolds
      New York Times
      December 26, 2012

      Anyone whose resolve to exercise in 2013 is a bit shaky
      might want to consider an emerging scientific view of
      human evolution. It suggests that we are clever today in
      part because a million years ago, we could outrun and
      outwalk most other mammals over long distances. Our
      brains were shaped and sharpened by movement, the idea
      goes, and we continue to require regular physical
      activity in order for our brains to function optimally.

      The role of physical endurance in shaping humankind has
      intrigued anthropologists and gripped the popular
      imagination for some time. In 2004, the evolutionary
      biologists Daniel E. Lieberman of Harvard and Dennis M.
      Bramble of the University of Utah published a seminal
      article in the journal Nature titled "Endurance Running
      and the Evolution of Homo," in which they posited that
      our bipedal ancestors survived by becoming endurance
      athletes, able to bring down swifter prey through sheer
      doggedness, jogging and plodding along behind them until
      the animals dropped.

      Endurance produced meals, which provided energy for
      mating, which meant that adept early joggers passed
      along their genes. In this way, natural selection drove
      early humans to become even more athletic, Dr. Lieberman
      and other scientists have written, their bodies
      developing longer legs, shorter toes, less hair and
      complicated inner-ear mechanisms to maintain balance and
      stability during upright ambulation. Movement shaped the
      human body.

      But simultaneously, in a development that until recently
      many scientists viewed as unrelated, humans were
      becoming smarter. Their brains were increasing rapidly
      in size.

      Today, humans have a brain that is about three times
      larger than would be expected, anthropologists say,
      given our species' body size in comparison with that of
      other mammals.

      To explain those outsized brains, evolutionary
      scientists have pointed to such occurrences as meat
      eating and, perhaps most determinatively, our early
      ancestors' need for social interaction. Early humans had
      to plan and execute hunts as a group, which required
      complicated thinking patterns and, it's been thought,
      rewarded the social and brainy with evolutionary
      success. According to that hypothesis, the evolution of
      the brain was driven by the need to think.

      But now some scientists are suggesting that physical
      activity also played a critical role in making our
      brains larger.

      To reach that conclusion, anthropologists began by
      looking at existing data about brain size and endurance
      capacity in a variety of mammals, including dogs, guinea
      pigs, foxes, mice, wolves, rats, civet cats, antelope,
      mongooses, goats, sheep and elands. They found a notable
      pattern. Species like dogs and rats that had a high
      innate endurance capacity, which presumably had evolved
      over millenniums, also had large brain volumes relative
      to their body size.

      The researchers also looked at recent experiments in
      which mice and rats were systematically bred to be
      marathon runners. Lab animals that willingly put in the
      most miles on running wheels were interbred, resulting
      in the creation of a line of lab animals that excelled
      at running.

      Interestingly, after multiple generations, these animals
      began to develop innately high levels of substances that
      promote tissue growth and health, including a protein
      called brain-derived neurotrophic factor, or BDNF. These
      substances are important for endurance performance. They
      also are known to drive brain growth.

      What all of this means, says David A. Raichlen, an
      anthropologist at the University of Arizona and an
      author of a new article about the evolution of human
      brains appearing in the January issue of Proceedings of
      the Royal Society Biology, is that physical activity may
      have helped to make early humans smarter.

      "We think that what happened" in our early hunter-
      gatherer ancestors, he says, is that the more athletic
      and active survived and, as with the lab mice, passed
      along physiological characteristics that improved their
      endurance, including elevated levels of BDNF.
      Eventually, these early athletes had enough BDNF
      coursing through their bodies that some could migrate
      from the muscles to the brain, where it nudged the
      growth of brain tissue.

      Those particular early humans then applied their growing
      ability to think and reason toward better tracking prey,
      becoming the best-fed and most successful from an
      evolutionary standpoint. Being in motion made them
      smarter, and being smarter now allowed them to move more

      And out of all of this came, eventually, an ability to
      understand higher math and invent iPads. But that was
      some time later.

      The broad point of this new notion is that if physical
      activity helped to mold the structure of our brains,
      then it most likely remains essential to brain health
      today, says John D. Polk, an associate professor of
      anthropology at the University of Illinois at Urbana-
      Champaign, and co-author, with Dr. Raichlen, of the new

      And there is scientific support for that idea. Recent
      studies have shown, he says, that "regular exercise,
      even walking," leads to more robust mental abilities,
      "beginning in childhood and continuing into old age."

      Of course, the hypothesis that jogging after prey helped
      to drive human brain evolution is just a hypothesis, Dr.
      Raichlen says, and almost unprovable.

      But it is compelling, says Harvard's Dr. Lieberman, who
      has worked with the authors of the new article. "I
      fundamentally agree that there is a deep evolutionary
      basis for the relationship between a healthy body and a
      healthy mind," he says, a relationship that makes the
      term "jogging your memory" more literal than most of us
      might have expected and provides a powerful incentive to
      be active in 2013.


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