Life expectancy is no exact science. There is no guarantee for anything; there is only a chance for it. Some persons for no known reasons reach well into old age, topping 90 and even 100 yrs old. Most of us cannot expect to reach this level of “ripeness”, however with proper diet, exercise and a little luck in genetics, persons suffering no great injuries or ailments can expect to live to fairly old ages.
Life expectancy over the centuries has risen greatly. There were actually two levels of expectancy in earlier centuries. Childhood disease often shortened ones” life span considerably, and so at birth you would have a fairly short life span expectancy that would be increased after reaching the milestone of mid-teens.
During the 13th century life expectancy after 15 yrs of age ranged from the early 40’s to the early 60,’s, the following century however, the life expectancy was lowered to only 55 due to the Black Death (Bubonic plague) that took millions, nearly half of the population of Europe succumbed to this dreaded disease. Thought long gone, this disease has actually had several reported cases throughout the world in recent years.
The centuries following the Black Death saw a rise in human life expectancy after 15, increasing from the fairly young age of 55 to as high 69 or 70 yrs of age, and then increasing slightly more to 71 years of age the following century. These numbers are considered the highest age possible, in reality people usually didn”t live much beyond 30 or 40 yrs of age due to various illnesses, even the flu that we see as a nuisance for about a week every year killed millions.
The average life expectancy in the early American colonies was a mere 25 yrs of age, and in New England 40% of children never reached maturity. The industrial revolution in England saw the average number of childhood deaths of children under the age of five years decrease from approximately 75% mortality rate to about 30%.
Jump ahead to the 21st century, the world Health organization determines not merely life expectancy, but an adults” healthy life expectancy. This is the number of years one can expect to live life in full health, excluding injury and disease. For reasons unknown, women tend to outlive men by a few years, an estimated 5.3 years longer in 2005,( an average of 80.1 years), down from 7.8 years longer in 1979.
Very few people reach the age of 100, the century milestone is reached by some people however, most of them women. There have been women in my family live to or beyond the 100 year marker. Japan, however, holds the highest number of centenarians, 347 per million persons, with The U.S. claiming 232 per million persons, a huge number when compared to only 32 per million in 1980.
Life expectancy is no promise, it is up too you to give yourself the greatest chance for longevity. Proper diet and exercise are key elements, and genetics play a great role. The lucky will experience no injury or illness to shorten their span, and the luckier few still will live not only a long life, but a healthy and productive one.