OK, let's get rid of this misnomer that "the average lifespan of humans in 1863 was 39 years old," or "...in 1900 was 43 years old," or whatever other fallacy the emails or statisticians say. I mean, it sounds like if you were 39 in the 1860's you had one foot in the grave, for Pete's sake!
Well, let's clear this mess up once and for all:
In general, folks in the 18th and 19th centuries lived nearly as long as we do today. Yes, it's true. If one would take the time to read journals of the period, or census records of long ago they would find a good majority of adults living to a ripe old age.
So why is this false information being passed around as fact? Because, technically, it is true - the average life span in 1862 may have been 39 years of age. The average lifespan. Now, take into account that, up until the mid 20th century, the infant mortality rate was pretty high. Er...I mean, very high. In some areas nearly one out of every two infants died before their first birthday. And then, from one year old to five years that percentage dropped. From five to 10 it dropped again. And so on and so forth. In other words, the older you got, the chances are you would probably see life into your 60's or 70's or even your 80's, just like today. Of course, death for women during childbirth was quite high, but we, in our modern day, have been able to prevent that situation from happening almost completely.
Yes, people did die of heart attacks, consumption (TB), cancer, pneumonia, and measles. People today die of cancer, heart attacks, and pneumonia as well. But, where 100 years ago they had consumption, we have aids. We also have a higher murder rate per capita here in the 21st century in comparison (here are some stats about this particular comment from the history news network (http://hnn.us/articles/871.html) :
By the 18th Century, colonial Americans were the most heavily armed people in the world," yet murders were "rare" and "few" involved guns "despite their wide availability."
American homicide remained low until the 1840s. Relatively modern rapid-fire weapons only became common after the Civil War when hundreds of thousands of military surplus revolvers and lever action rifles were sold. Yet, far from rising in the post-Civil War era, homicide fell off sharply from the 1870s to 1900 -- despite the 1870s mass marketing of cheap "Saturday Night Specials."
Anyhow, what it boils down to is that if you ever see any of these average lifespan stats, take them with a grain of salt and put the whole thing into its perspective.