This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 12th (it came out in 2015), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

If you are a user of my textbook and would like to suggest a blog post idea, please email me at: john.weeks@sdsu.edu

Tuesday, December 15, 2015

Science Has to Overcome Biology to Give Us a Longer Life Expectancy

Here and Now this morning on NPR had a very interesting conversation with Lee Goldman, who is Dean of Medicine at Columbia University. He has just published a book titled Too Much of a Good Thing: How Four Key Survivor Traits Are Now Killing Us. At first, I thought he might just be parroting the things about the nutrition transition that Barry Popkin has been teaching us for years, as I recently noted.  Yes, there is that, but he has other points to make, as well. Here are the highlights:
Too Much of a Good Thing focuses on the four key human survival traits, without which we wouldn’t be here today:
Appetite and the imperative for calories. Early humans avoided starvation by being able to gorge themselves whenever food was available. Now that same tendency to eat more than our bodies really need explains why 35 percent of Americans are obese and have an increased risk of developing diabetes, heart disease, and even cancer.
Our need for water and salt. Our ancestors continually faced the possibility of fatal dehydration, especially if they exercised and sweated, so their bodies had to crave and conserve both water and salt. Today, many Americans consume far more salt than they need, and this excess salt combined with the same internal hormones that conserve salt and water are the reasons why 30 percent of us have high blood pressure — significantly increasing our risks of heart disease, stroke, and kidney failure.
Knowing when to fight, when to flee, and when to be submissive. In prehistoric societies, up to 25 percent of deaths were caused by violence, so it was critical to be hypervigilant, always worrying about potentially getting killed. But as the world got safer, violence declined. Suicide is now much more common in the United States than murder and fatal animal attacks. Why? Our hypervigilance, fears, and worrying contribute to a growing epidemic of anxiety, depression, and post-traumatic stress — and the suicides that can result.
The ability to form blood clots so we won’t bleed to death. Because of their considerable risk of bleeding from trauma and childbirth, early humans needed to be able to clot quickly and efficiently. Now, with the advent of everything from bandages to blood transfusions, blood clots are more likely to kill us than excessive bleeding. Most heart attacks and strokes — the leading causes of death in today’s society — are a direct result of blood clots that block the flow of arterial blood to our hearts and brains. And long car rides and plane trips, unknown to our distant ancestors, can cause dangerous and sometimes fatal clots in our veins.
The punchline of the interview is his comment that our biological makeup is designed to ensure that we live to age 25 (the mean age of reproduction), so we have to overcome those traits in order to live longer. Don't think you can do this on your own! Keep taking your meds...

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