According to the US 12th Census 1891-1900 report, the life expectancy for the average American was 48 yrs old for males and 51 for females.
By 1950 it had increased to 65.6 for men and 71.1 for women. Ref:
For 2004 the average age was 75.2 men and 80.4 women. Ref: U.S. Census Bureau 2008 Statistical Abstract
From the 1st President George Washington to the 25t President William McKinley each have been at or above the average life expectancy for that particular period in time. Their average age at the time they took office was 55. This meant they were 6 yrs older than the average life expectancy and considered old for their time. This is a statistic, Ref: United States Presidents by age
The fact is for the first 25 Presidents every one was above the average life expectancy at the time they took office.
It wasn't until the election of Herbert Hoover in 1929 that the situation turned around. Hoover was 54 yrs old when he was sworn in and the life expectancy for men was 58.1 After Hoover every President, except Harry Truman and Ronald Reagan, have been below the average life expectancy for men. Harry Truman assumed office at the age of 60 yrs 11 months 4 days in 1945 after the death of Franklin Roosevelt. The average life expectancy at the time was 60.8 Ronald Reagan was 69 years 11 months 14 days in 1981 and the life expectancy was 69.9
Due to the increase in the average life expectancy for the average American, today its projected to reach 75.5 for men and 81.4 for women by 2010, the average age for Presidents at the time they take office is well below the average life expectancy age. Since Hoover it has averaged out to be 54.5 at the age of taking office.
So looking at all of these numbers, what does it tell us. For me it says most of our past Presidents could be considered old at the time they were sworn into office. It tells me, in comparison with life expectancy at the time of their presidency only John Kennedy and Bill Clinton could be considered young. It says age cannot be a factor since we have had some pretty good Presidents that many would have considered old at the time. Washington, Adams, Jefferson, Madison, Lincoln, Wilson, Franklin Roosevelt, Truman, Eisenhower and Reagan were all considered old at the time.
Maybe we had a different outlook at the time these men were elected. Maybe we had a totally different respect for older people. Maybe we thought with a little age came a lot of experience and knowledge. Maybe we should return to those days.