Posted by: drwbortz | April 22, 2010

Roots: What’s the relationship between exercise & evolution?

I’ve always had a substantial interest in anthropology as a pillar of trying to understand what it means to be human.  I actually met my wife at Harvard summer school, where in 1949 I was attending my first formal course on this topic. This interest festered and lay somewhat dormant during my training years, which were fixated on learning clinical medicine and biochemical research, and thirty years of medical practice at the Palo Alto Medical Clinic and Stanford University Medical Center.

But the opportunity in 1980 to take an extended sabbatical leave from my patient care duties was delicious.  Accordingly, Ruth Anne and I strapped our backpacks on and left JFK on October 1, 1980, and headed directly east to Dakar, Senegal, where three days later, she celebrated her 50th birthday in a never to be forgotten brilliant fishermen’s village on the shore. The locals joined in the chorus. From there a month’s trekking down the west coast of Africa to the awful city of Lagos, Nigeria, the absolute cesspool of humanity, where fortunately we had a medical contact.

We saw a lot.  I had an interest in voodoo medicine, which I saw at first hand, in West Africa.  Then the flight to Nairobi, where I had obtained an unenthusiastic invitation from Richard Leakey to hang around his famous laboratory.  “What does a medical doctor know about old bones?”  His father, Louis and mother Mary were the archetypic anthropologists.  Yet enthusiasm and funds are a good recommendation, so I settled into my pattern of four days a week in Leakey’s library for research study, and three days a week to visit the game parks, Kilimanjaro, Rwanda , Masai Mara, Amboselli, etc.  We brought three of our four children over for long visits to indulge the extraordinary lessons which Africa presents.  It was a fabulous “roots” experience.  Digging in the dust of the Olduvai Gorge, and surveying the shorelines near where Lucy was unearthed reshaped our lives in a way to which only our previous Himalayan adventures could compare.

While in Africa I had three personal ambitions.  First was to explore the frequency and practice of voodoo folk medicine.  Second was to survey the role of older people in the hunter-gatherer culture. And third, to seek the evidence of the physical activity pattern of our old, old ancestors.  It is the last of these three ambitions that held the most promise for exposition. I scrounged enough insights in the Nairobi library to generate sufficient material for a major paper, which I subsequently wrote in the Journal of Human Evolution entitled “Physical Exercise as an Evolutionary Force.”

The library in Nairobi was like Valhalla to the world’s anthropologists. It was where their gathering place, and I had the opportunity to exchange ideas with them on the formative elements of our species.  While the anthropologists were very interested in territoriality, aggression, on nutritional habits, etc. I suggested that maybe  physical exercise was another contributing feature to the formation of our species.  The paper, (of which I’m very proud,) derived from this speculation, and said that our early ancestors left the jungle canopy, where our chimpanzee cousins remain, about 5 million years or so ago.  Our great, great great, grand-daddies and grand-mas went out on the Serengeti, where they adapted an upright stance and a persistence hunting way of life.  This led to a host of gene expression events, such as loss of body hair and a prodigious capacity to sweat.  Among other things, it also gave birth to the growth of the human brain from its chimp size of 500 cc to our current size of 1100 cc.  Interestingly, the Neanderthals who lived between Lucy and us had even bigger brains than ours, but they were also more physically active.  Domestication leads to smaller brains and other adaptive degradations. BDNF ( brain derived neurotrophic factor), is elevated by exercise.

The high mobility habit of our ancestors was re-suggested recently in an article in  Nature by David Lieberman of Harvard University and Dennis Bramble from the University of Utah, who seem to have been aware of my similar work of twenty years previously.

Our primitive exercise pattern has much to tell us about our current condition.  In 2005 the International Journal of Obesity presented a paper by workers at Columbia University and  Verona University Medical School.   These workers calculated that our primitive ancestors had an exercise program that was roughly 160% of ours, and that we, today, would need to add a 12-mile walk to catch up .

The medical implications of this downgrading of our physical activity pattern is regularly apparent in our obesity statistics, as well as in many of the other components of the Disuse Syndrome, of which I will write later. The CDC projects that our current generation of youngsters is the first in the history of our country who may not live as long as their parents.  Therefore, despite spending huge amounts of money and having incredibly more information, we are living less healthy lives with a shortened life expectation. We are now zoo animals, and therefore must be very carefully tended.  We were born free, but we are now degrading our physically active pedigree. This has little to do with the medical system but has only to do with our culture, which has seduced us by way of electricity and the wheel.

We need to rediscover our legs, which have enabled our survival, until now.

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Responses

  1. The problem is how to motivate people to use their legs and get off the sofa, especially working people with children?


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