I’ve been reading some fascinating discussions in the Forums that reflect common misconceptions many people hold about height and longevity, and what determines them. There are indeed ways to eat better and to live in ways to improve the quality of your life for as long as you live. However, historically speaking, there’s one thing far outstripping all of those that has been the bottom line in why modern people are taller (on average), and why they live longer (again, on average). It’s the reduction of disease through access to improved science and medicine, which includes sanitation and hygiene.
Part of the confusion is because people interchange the different concepts of longevity (the length of a physical life) and life expectancy (a mathematical projection of survival in years). Longevity has a well-established limit, at least as far as fact goes. If all voluntary factors were consistently pursued to advantage, and your family genetics supported it, you might possibly live to be 120-125 years old. Very, very, VERY few individuals live an entirely advantageous, risk-averse life supported by the best possible genes. Some believe there have been historical cases of individuals living much longer than that, but the evidence supporting these cases is absent reliable, objective documentation.
The reasons for this limit are the sum of everything we have learned so far about the human body’s ability to repair itself, combined with what we are able to replace or repair using technology. The big obstacle is nerve tissue. The central nervous system goes from the brain down to the other end of the spinal cord inside the vertebrae of your back. For the most part, when it’s gone, it’s gone. We can rebuild and replace severely damaged joints and transplant some organs, but we can’t regenerate or repair spinal cords yet, and when too much of your brain dies it’s “game over”, no exceptions. The neural networks in the brain are so valuable and irreplaceable that over time we have evolved an unknown quantity of redundant nerve tissue in there. That’s why some people with brain injury are able to recover function. There’s extra, and what remains can sometimes be re-trained.
Life expectancy is a concept misunderstood by many. It’s a mathematical average applied to specific populations during a historical time period. It is not how long you as an individual are guaranteed, or even likely, to live. It is not determined by how long the oldest individuals in your population group live. The average is mostly determined by the rates of mortality of infants and young children. When you read a statistic like “Life Expectancy by Country”, it is a reflection of the quality and ability to prevent and reduce the diseases that primarily kill little ones.
The life expectancy of modern people is longer not because we have better nutrition available, but because fewer babies die. Science has promoted better hygiene and improved sanitation, and it prevents and reduces the diseases that used to kill the young with greater regularity in earlier times. In the past, if you survived to adulthood, and that used to be a bigger “if”, your life expectancy was the same as it is for modern people. Those who were lucky enough to get to be old reached the same average ages in the year 1200 as they do now.
Life expectancy averages have sometimes been impacted by pandemics. Because the “Black Death” of the 14th Century killed half or more of the population of Europe (80% of those who contracted it), life expectancy there was halved. It took 150 years for those populations to recover and stabilize.
How does this relate to tallness? When you are young and growing, diseases prevent the body from utilizing nutrients toward growth. You have to burn the fuel to fight the germs instead, in order to survive at all. THAT’S why modern people are taller. The reduction and prevention of disease means more individuals are able to use what they eat to grow on, and because fewer babies die, more get to grow up.
There are also some interesting political aspects of health care affecting the trends of modern populations toward being taller and living longer. From 1800 to 1945, the U.S. had the tallest average height, because all the positive factors were in place; genetic, nutrition and access to health care. Americans in the first half of the 20th Century were also at or near the top of the life expectancy list. Since the end of World War II in 1945, a number of nations instituted variations of universal, single-payer health care systems, what we here derisively call “socialized medicine”. Guess who the tallest people are now? The Dutch, Icelanders, Scandinavians in general, Germans, Belgians and the Swiss are all taller on average than Americans. They all have lower infant mortality rates and higher life expectancy too.
Let’s not forget to compare some of the countries with more of the genes for being shorter. The shorter Japanese, Israelis, French, Canadians, Italians and citizens of the UK all have greater life expectancy than Americans. In fact, the USA is now between 29th and 38th on this list, depending on different sources, below South Korea, Denmark and Cuba. Where is the U.S. currently on the infant mortality rate list? We are number 34, right below the countries previously listed as well as places like the Czech Republic, Slovenia and Spain.
I’m all for eating right, regulating stress through meditation practices and making wiser lifestyle choices. All those things are important. But if you want to live a long time with a high quality of life, you will mathematically improve your chances the most by doing what you can to see that you and your kids get good basic medical care. That, and try to get yourself born into a healthy family. And maybe move to a country farther north.